add realtime linux preempt_rt patch

Enable Kernel options for Realtime, HZ and HighRes Timer
in menuconfig.

target/linux/config/Config.in.addons

@@ -3,22 +3,26 @@
 
 config ADK_KERNEL_ADDON_YAFFS2
 	default y if ADK_TARGET_WITH_NAND
-	boolean
+	bool
 
 config ADK_KERNEL_ADDON_GRSEC
-	boolean
+	bool
 	depends on ADK_KERNEL_VERSION_3_14
 
 config ADK_KERNEL_ADDON_MPTCP
-	boolean
+	bool
 	depends on ADK_KERNEL_VERSION_3_14
 
 config ADK_KERNEL_ADDON_FBLOGO
-	boolean
+	bool
 	depends on ADK_KERNEL_VERSION_3_14
 
 config ADK_KERNEL_ADDON_DIETNET
-	boolean
+	bool
 	depends on ADK_KERNEL_VERSION_3_14
 	depends on ADK_KERNEL_VERSION_3_12
 	depends on ADK_KERNEL_VERSION_3_10
+
+config ADK_KERNEL_ADDON_LINUXRT
+	bool
+	depends on ADK_KERNEL_VERSION_3_18

target/linux/config/Config.in.kernel

@@ -227,11 +227,6 @@ config ADK_KERNEL_HIGHMEM
 	help
 	  Enable high memory support.
 
-config ADK_KERNEL_PREEMPT
-	bool "Enable preemptive kernel"
-	help
-	  Enable preemptive mode.
-
 config ADK_KERNEL_BCM2708_DT
 	bool "Enable Devicetree support"
 	depends on ADK_TARGET_SYSTEM_RASPBERRY_PI
@@ -248,6 +243,52 @@ config ADK_KERNEL_CC_OPTIMIZE_FOR_SIZE
 	depends on !ADK_TARGET_ARCH_MICROBLAZE
 	default y
 
+config ADK_KERNEL_PREEMPT
+	bool "Enable preemptive kernel"
+	help
+	  Enable preemptive mode.
+
+config ADK_KERNEL_PREEMPT_RT_FULL
+        bool "Enable Realtime support"
+        select ADK_KERNEL_ADDON_LINUXRT
+        help
+	  https://www.kernel.org/pub/linux/kernel/projects/rt/3.18/
+
+
+choice
+prompt "tick configuration"
+
+config ADK_KERNEL_NO_HZ_IDLE
+	bool "no HZ IDLE, dynamic tick"
+
+config ADK_KERNEL_NO_HZ_FULL
+	bool "no HZ FULL, dynamic tick"
+
+config ADK_KERNEL_HZ_PERIODIC
+	bool "periodic tick"
+
+endchoice
+
+choice
+prompt "HZ"
+depends on ADK_KERNEL_HZ_PERIODIC
+
+config ADK_KERNEL_HZ_100
+	bool "100 HZ"
+
+config ADK_KERNEL_HZ_500
+	bool "500 HZ"
+
+config ADK_KERNEL_HZ_1000
+	bool "1000 HZ"
+
+endchoice
+
+config ADK_KERNEL_HIGH_RES_TIMERS
+	bool "Enable high resolution timers"
+	help
+
+
 choice
 prompt "Page size"
 depends on ADK_TARGET_ARCH_MIPS64

target/linux/kernel.config

@@ -1,7 +1,6 @@
 CONFIG_DEFAULT_HOSTNAME="openadk"
 CONFIG_CMDLINE_BOOL=y
 CONFIG_CMDLINE=""
-CONFIG_NO_HZ=y
 CONFIG_SYSVIPC=y
 CONFIG_SYSVIPC_SYSCTL=y
 CONFIG_POSIX_MQUEUE=y

target/linux/patches/3.18.8/patch-linuxrt

@@ -0,0 +1,23744 @@
+diff -Nur linux-3.18.8.orig/arch/alpha/mm/fault.c linux-3.18.8/arch/alpha/mm/fault.c
+--- linux-3.18.8.orig/arch/alpha/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/alpha/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -107,7 +107,7 @@
+ 
+ 	/* If we're in an interrupt context, or have no user context,
+ 	   we must not take the fault.  */
+-	if (!mm || in_atomic())
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ #ifdef CONFIG_ALPHA_LARGE_VMALLOC
+diff -Nur linux-3.18.8.orig/arch/arm/include/asm/cmpxchg.h linux-3.18.8/arch/arm/include/asm/cmpxchg.h
+--- linux-3.18.8.orig/arch/arm/include/asm/cmpxchg.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/include/asm/cmpxchg.h	2015-03-03 08:05:17.000000000 +0100
+@@ -129,6 +129,8 @@
+ 
+ #else	/* min ARCH >= ARMv6 */
+ 
++#define __HAVE_ARCH_CMPXCHG 1
++
+ extern void __bad_cmpxchg(volatile void *ptr, int size);
+ 
+ /*
+diff -Nur linux-3.18.8.orig/arch/arm/include/asm/futex.h linux-3.18.8/arch/arm/include/asm/futex.h
+--- linux-3.18.8.orig/arch/arm/include/asm/futex.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/include/asm/futex.h	2015-03-03 08:05:17.000000000 +0100
+@@ -93,6 +93,8 @@
+ 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+ 		return -EFAULT;
+ 
++	preempt_disable_rt();
++
+ 	__asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
+ 	"1:	" TUSER(ldr) "	%1, [%4]\n"
+ 	"	teq	%1, %2\n"
+@@ -104,6 +106,8 @@
+ 	: "cc", "memory");
+ 
+ 	*uval = val;
++
++	preempt_enable_rt();
+ 	return ret;
+ }
+ 
+diff -Nur linux-3.18.8.orig/arch/arm/include/asm/switch_to.h linux-3.18.8/arch/arm/include/asm/switch_to.h
+--- linux-3.18.8.orig/arch/arm/include/asm/switch_to.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/include/asm/switch_to.h	2015-03-03 08:05:17.000000000 +0100
+@@ -3,6 +3,13 @@
+ 
+ #include <linux/thread_info.h>
+ 
++#if defined CONFIG_PREEMPT_RT_FULL && defined CONFIG_HIGHMEM
++void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p);
++#else
++static inline void
++switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
++#endif
++
+ /*
+  * For v7 SMP cores running a preemptible kernel we may be pre-empted
+  * during a TLB maintenance operation, so execute an inner-shareable dsb
+@@ -22,6 +29,7 @@
+ 
+ #define switch_to(prev,next,last)					\
+ do {									\
++	switch_kmaps(prev, next);					\
+ 	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));	\
+ } while (0)
+ 
+diff -Nur linux-3.18.8.orig/arch/arm/include/asm/thread_info.h linux-3.18.8/arch/arm/include/asm/thread_info.h
+--- linux-3.18.8.orig/arch/arm/include/asm/thread_info.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/include/asm/thread_info.h	2015-03-03 08:05:17.000000000 +0100
+@@ -51,6 +51,7 @@
+ struct thread_info {
+ 	unsigned long		flags;		/* low level flags */
+ 	int			preempt_count;	/* 0 => preemptable, <0 => bug */
++	int			preempt_lazy_count;	/* 0 => preemptable, <0 => bug */
+ 	mm_segment_t		addr_limit;	/* address limit */
+ 	struct task_struct	*task;		/* main task structure */
+ 	struct exec_domain	*exec_domain;	/* execution domain */
+@@ -149,6 +150,7 @@
+ #define TIF_SIGPENDING		0
+ #define TIF_NEED_RESCHED	1
+ #define TIF_NOTIFY_RESUME	2	/* callback before returning to user */
++#define TIF_NEED_RESCHED_LAZY	3
+ #define TIF_UPROBE		7
+ #define TIF_SYSCALL_TRACE	8
+ #define TIF_SYSCALL_AUDIT	9
+@@ -162,6 +164,7 @@
+ #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
+ #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+ #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
++#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
+ #define _TIF_UPROBE		(1 << TIF_UPROBE)
+ #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
+ #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
+diff -Nur linux-3.18.8.orig/arch/arm/Kconfig linux-3.18.8/arch/arm/Kconfig
+--- linux-3.18.8.orig/arch/arm/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/Kconfig	2015-03-03 08:05:17.000000000 +0100
+@@ -62,6 +62,7 @@
+ 	select HAVE_PERF_EVENTS
+ 	select HAVE_PERF_REGS
+ 	select HAVE_PERF_USER_STACK_DUMP
++	select HAVE_PREEMPT_LAZY
+ 	select HAVE_RCU_TABLE_FREE if (SMP && ARM_LPAE)
+ 	select HAVE_REGS_AND_STACK_ACCESS_API
+ 	select HAVE_SYSCALL_TRACEPOINTS
+diff -Nur linux-3.18.8.orig/arch/arm/kernel/asm-offsets.c linux-3.18.8/arch/arm/kernel/asm-offsets.c
+--- linux-3.18.8.orig/arch/arm/kernel/asm-offsets.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/kernel/asm-offsets.c	2015-03-03 08:05:17.000000000 +0100
+@@ -64,6 +64,7 @@
+   BLANK();
+   DEFINE(TI_FLAGS,		offsetof(struct thread_info, flags));
+   DEFINE(TI_PREEMPT,		offsetof(struct thread_info, preempt_count));
++  DEFINE(TI_PREEMPT_LAZY,	offsetof(struct thread_info, preempt_lazy_count));
+   DEFINE(TI_ADDR_LIMIT,		offsetof(struct thread_info, addr_limit));
+   DEFINE(TI_TASK,		offsetof(struct thread_info, task));
+   DEFINE(TI_EXEC_DOMAIN,	offsetof(struct thread_info, exec_domain));
+diff -Nur linux-3.18.8.orig/arch/arm/kernel/entry-armv.S linux-3.18.8/arch/arm/kernel/entry-armv.S
+--- linux-3.18.8.orig/arch/arm/kernel/entry-armv.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/kernel/entry-armv.S	2015-03-03 08:05:17.000000000 +0100
+@@ -207,11 +207,18 @@
+ #ifdef CONFIG_PREEMPT
+ 	get_thread_info tsk
+ 	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
+-	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
+ 	teq	r8, #0				@ if preempt count != 0
++	bne	1f				@ return from exeption
++	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
++	tst	r0, #_TIF_NEED_RESCHED		@ if NEED_RESCHED is set
++	blne	svc_preempt			@ preempt!
++
++	ldr	r8, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
++	teq	r8, #0				@ if preempt lazy count != 0
+ 	movne	r0, #0				@ force flags to 0
+-	tst	r0, #_TIF_NEED_RESCHED
++	tst	r0, #_TIF_NEED_RESCHED_LAZY
+ 	blne	svc_preempt
++1:
+ #endif
+ 
+ 	svc_exit r5, irq = 1			@ return from exception
+@@ -226,6 +233,8 @@
+ 1:	bl	preempt_schedule_irq		@ irq en/disable is done inside
+ 	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS
+ 	tst	r0, #_TIF_NEED_RESCHED
++	bne	1b
++	tst	r0, #_TIF_NEED_RESCHED_LAZY
+ 	reteq	r8				@ go again
+ 	b	1b
+ #endif
+diff -Nur linux-3.18.8.orig/arch/arm/kernel/process.c linux-3.18.8/arch/arm/kernel/process.c
+--- linux-3.18.8.orig/arch/arm/kernel/process.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/kernel/process.c	2015-03-03 08:05:17.000000000 +0100
+@@ -431,6 +431,30 @@
+ }
+ 
+ #ifdef CONFIG_MMU
++/*
++ * CONFIG_SPLIT_PTLOCK_CPUS results in a page->ptl lock.  If the lock is not
++ * initialized by pgtable_page_ctor() then a coredump of the vector page will
++ * fail.
++ */
++static int __init vectors_user_mapping_init_page(void)
++{
++	struct page *page;
++	unsigned long addr = 0xffff0000;
++	pgd_t *pgd;
++	pud_t *pud;
++	pmd_t *pmd;
++
++	pgd = pgd_offset_k(addr);
++	pud = pud_offset(pgd, addr);
++	pmd = pmd_offset(pud, addr);
++	page = pmd_page(*(pmd));
++
++	pgtable_page_ctor(page);
++
++	return 0;
++}
++late_initcall(vectors_user_mapping_init_page);
++
+ #ifdef CONFIG_KUSER_HELPERS
+ /*
+  * The vectors page is always readable from user space for the
+diff -Nur linux-3.18.8.orig/arch/arm/kernel/signal.c linux-3.18.8/arch/arm/kernel/signal.c
+--- linux-3.18.8.orig/arch/arm/kernel/signal.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/kernel/signal.c	2015-03-03 08:05:17.000000000 +0100
+@@ -574,7 +574,8 @@
+ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
+ {
+ 	do {
+-		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
++		if (likely(thread_flags & (_TIF_NEED_RESCHED |
++					   _TIF_NEED_RESCHED_LAZY))) {
+ 			schedule();
+ 		} else {
+ 			if (unlikely(!user_mode(regs)))
+diff -Nur linux-3.18.8.orig/arch/arm/kernel/smp.c linux-3.18.8/arch/arm/kernel/smp.c
+--- linux-3.18.8.orig/arch/arm/kernel/smp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/kernel/smp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -506,12 +506,14 @@
+ }
+ 
+ #ifdef CONFIG_IRQ_WORK
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void arch_irq_work_raise(void)
+ {
+ 	if (arch_irq_work_has_interrupt())
+ 		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
+ }
+ #endif
++#endif
+ 
+ #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+ void tick_broadcast(const struct cpumask *mask)
+diff -Nur linux-3.18.8.orig/arch/arm/kernel/unwind.c linux-3.18.8/arch/arm/kernel/unwind.c
+--- linux-3.18.8.orig/arch/arm/kernel/unwind.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/kernel/unwind.c	2015-03-03 08:05:17.000000000 +0100
+@@ -93,7 +93,7 @@
+ static const struct unwind_idx *__origin_unwind_idx;
+ extern const struct unwind_idx __stop_unwind_idx[];
+ 
+-static DEFINE_SPINLOCK(unwind_lock);
++static DEFINE_RAW_SPINLOCK(unwind_lock);
+ static LIST_HEAD(unwind_tables);
+ 
+ /* Convert a prel31 symbol to an absolute address */
+@@ -201,7 +201,7 @@
+ 		/* module unwind tables */
+ 		struct unwind_table *table;
+ 
+-		spin_lock_irqsave(&unwind_lock, flags);
++		raw_spin_lock_irqsave(&unwind_lock, flags);
+ 		list_for_each_entry(table, &unwind_tables, list) {
+ 			if (addr >= table->begin_addr &&
+ 			    addr < table->end_addr) {
+@@ -213,7 +213,7 @@
+ 				break;
+ 			}
+ 		}
+-		spin_unlock_irqrestore(&unwind_lock, flags);
++		raw_spin_unlock_irqrestore(&unwind_lock, flags);
+ 	}
+ 
+ 	pr_debug("%s: idx = %p\n", __func__, idx);
+@@ -530,9 +530,9 @@
+ 	tab->begin_addr = text_addr;
+ 	tab->end_addr = text_addr + text_size;
+ 
+-	spin_lock_irqsave(&unwind_lock, flags);
++	raw_spin_lock_irqsave(&unwind_lock, flags);
+ 	list_add_tail(&tab->list, &unwind_tables);
+-	spin_unlock_irqrestore(&unwind_lock, flags);
++	raw_spin_unlock_irqrestore(&unwind_lock, flags);
+ 
+ 	return tab;
+ }
+@@ -544,9 +544,9 @@
+ 	if (!tab)
+ 		return;
+ 
+-	spin_lock_irqsave(&unwind_lock, flags);
++	raw_spin_lock_irqsave(&unwind_lock, flags);
+ 	list_del(&tab->list);
+-	spin_unlock_irqrestore(&unwind_lock, flags);
++	raw_spin_unlock_irqrestore(&unwind_lock, flags);
+ 
+ 	kfree(tab);
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-at91/at91rm9200_time.c linux-3.18.8/arch/arm/mach-at91/at91rm9200_time.c
+--- linux-3.18.8.orig/arch/arm/mach-at91/at91rm9200_time.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-at91/at91rm9200_time.c	2015-03-03 08:05:17.000000000 +0100
+@@ -135,6 +135,7 @@
+ 		break;
+ 	case CLOCK_EVT_MODE_SHUTDOWN:
+ 	case CLOCK_EVT_MODE_UNUSED:
++		remove_irq(NR_IRQS_LEGACY + AT91_ID_SYS, &at91rm9200_timer_irq);
+ 	case CLOCK_EVT_MODE_RESUME:
+ 		irqmask = 0;
+ 		break;
+diff -Nur linux-3.18.8.orig/arch/arm/mach-exynos/platsmp.c linux-3.18.8/arch/arm/mach-exynos/platsmp.c
+--- linux-3.18.8.orig/arch/arm/mach-exynos/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-exynos/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -137,7 +137,7 @@
+ 	return (void __iomem *)(S5P_VA_SCU);
+ }
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ static void exynos_secondary_init(unsigned int cpu)
+ {
+@@ -150,8 +150,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
+@@ -165,7 +165,7 @@
+ 	 * Set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * The secondary processor is waiting to be released from
+@@ -192,7 +192,7 @@
+ 
+ 		if (timeout == 0) {
+ 			printk(KERN_ERR "cpu1 power enable failed");
+-			spin_unlock(&boot_lock);
++			raw_spin_unlock(&boot_lock);
+ 			return -ETIMEDOUT;
+ 		}
+ 	}
+@@ -242,7 +242,7 @@
+ 	 * calibrations, then wait for it to finish
+ 	 */
+ fail:
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return pen_release != -1 ? ret : 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-hisi/platmcpm.c linux-3.18.8/arch/arm/mach-hisi/platmcpm.c
+--- linux-3.18.8.orig/arch/arm/mach-hisi/platmcpm.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-hisi/platmcpm.c	2015-03-03 08:05:17.000000000 +0100
+@@ -57,7 +57,7 @@
+ 
+ static void __iomem *sysctrl, *fabric;
+ static int hip04_cpu_table[HIP04_MAX_CLUSTERS][HIP04_MAX_CPUS_PER_CLUSTER];
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ static u32 fabric_phys_addr;
+ /*
+  * [0]: bootwrapper physical address
+@@ -104,7 +104,7 @@
+ 	if (cluster >= HIP04_MAX_CLUSTERS || cpu >= HIP04_MAX_CPUS_PER_CLUSTER)
+ 		return -EINVAL;
+ 
+-	spin_lock_irq(&boot_lock);
++	raw_spin_lock_irq(&boot_lock);
+ 
+ 	if (hip04_cpu_table[cluster][cpu])
+ 		goto out;
+@@ -133,7 +133,7 @@
+ 	udelay(20);
+ out:
+ 	hip04_cpu_table[cluster][cpu]++;
+-	spin_unlock_irq(&boot_lock);
++	raw_spin_unlock_irq(&boot_lock);
+ 
+ 	return 0;
+ }
+@@ -149,7 +149,7 @@
+ 
+ 	__mcpm_cpu_going_down(cpu, cluster);
+ 
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 	BUG_ON(__mcpm_cluster_state(cluster) != CLUSTER_UP);
+ 	hip04_cpu_table[cluster][cpu]--;
+ 	if (hip04_cpu_table[cluster][cpu] == 1) {
+@@ -162,7 +162,7 @@
+ 
+ 	last_man = hip04_cluster_is_down(cluster);
+ 	if (last_man && __mcpm_outbound_enter_critical(cpu, cluster)) {
+-		spin_unlock(&boot_lock);
++		raw_spin_unlock(&boot_lock);
+ 		/* Since it's Cortex A15, disable L2 prefetching. */
+ 		asm volatile(
+ 		"mcr	p15, 1, %0, c15, c0, 3 \n\t"
+@@ -173,7 +173,7 @@
+ 		hip04_set_snoop_filter(cluster, 0);
+ 		__mcpm_outbound_leave_critical(cluster, CLUSTER_DOWN);
+ 	} else {
+-		spin_unlock(&boot_lock);
++		raw_spin_unlock(&boot_lock);
+ 		v7_exit_coherency_flush(louis);
+ 	}
+ 
+@@ -192,7 +192,7 @@
+ 	       cpu >= HIP04_MAX_CPUS_PER_CLUSTER);
+ 
+ 	count = TIMEOUT_MSEC / POLL_MSEC;
+-	spin_lock_irq(&boot_lock);
++	raw_spin_lock_irq(&boot_lock);
+ 	for (tries = 0; tries < count; tries++) {
+ 		if (hip04_cpu_table[cluster][cpu]) {
+ 			ret = -EBUSY;
+@@ -202,10 +202,10 @@
+ 		data = readl_relaxed(sysctrl + SC_CPU_RESET_STATUS(cluster));
+ 		if (data & CORE_WFI_STATUS(cpu))
+ 			break;
+-		spin_unlock_irq(&boot_lock);
++		raw_spin_unlock_irq(&boot_lock);
+ 		/* Wait for clean L2 when the whole cluster is down. */
+ 		msleep(POLL_MSEC);
+-		spin_lock_irq(&boot_lock);
++		raw_spin_lock_irq(&boot_lock);
+ 	}
+ 	if (tries >= count)
+ 		goto err;
+@@ -220,10 +220,10 @@
+ 	}
+ 	if (tries >= count)
+ 		goto err;
+-	spin_unlock_irq(&boot_lock);
++	raw_spin_unlock_irq(&boot_lock);
+ 	return 0;
+ err:
+-	spin_unlock_irq(&boot_lock);
++	raw_spin_unlock_irq(&boot_lock);
+ 	return ret;
+ }
+ 
+@@ -235,10 +235,10 @@
+ 	cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ 	cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+ 
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 	if (!hip04_cpu_table[cluster][cpu])
+ 		hip04_cpu_table[cluster][cpu] = 1;
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static void __naked hip04_mcpm_power_up_setup(unsigned int affinity_level)
+diff -Nur linux-3.18.8.orig/arch/arm/mach-omap2/omap-smp.c linux-3.18.8/arch/arm/mach-omap2/omap-smp.c
+--- linux-3.18.8.orig/arch/arm/mach-omap2/omap-smp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-omap2/omap-smp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -43,7 +43,7 @@
+ /* SCU base address */
+ static void __iomem *scu_base;
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ void __iomem *omap4_get_scu_base(void)
+ {
+@@ -74,8 +74,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle)
+@@ -89,7 +89,7 @@
+ 	 * Set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * Update the AuxCoreBoot0 with boot state for secondary core.
+@@ -166,7 +166,7 @@
+ 	 * Now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-prima2/platsmp.c linux-3.18.8/arch/arm/mach-prima2/platsmp.c
+--- linux-3.18.8.orig/arch/arm/mach-prima2/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-prima2/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -23,7 +23,7 @@
+ static void __iomem *scu_base;
+ static void __iomem *rsc_base;
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ static struct map_desc scu_io_desc __initdata = {
+ 	.length		= SZ_4K,
+@@ -56,8 +56,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static struct of_device_id rsc_ids[]  = {
+@@ -95,7 +95,7 @@
+ 	/* make sure write buffer is drained */
+ 	mb();
+ 
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * The secondary processor is waiting to be released from
+@@ -127,7 +127,7 @@
+ 	 * now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return pen_release != -1 ? -ENOSYS : 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-qcom/platsmp.c linux-3.18.8/arch/arm/mach-qcom/platsmp.c
+--- linux-3.18.8.orig/arch/arm/mach-qcom/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-qcom/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -46,7 +46,7 @@
+ 
+ extern void secondary_startup(void);
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+ static void __ref qcom_cpu_die(unsigned int cpu)
+@@ -60,8 +60,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static int scss_release_secondary(unsigned int cpu)
+@@ -284,7 +284,7 @@
+ 	 * set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * Send the secondary CPU a soft interrupt, thereby causing
+@@ -297,7 +297,7 @@
+ 	 * now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return ret;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-spear/platsmp.c linux-3.18.8/arch/arm/mach-spear/platsmp.c
+--- linux-3.18.8.orig/arch/arm/mach-spear/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-spear/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -32,7 +32,7 @@
+ 	sync_cache_w(&pen_release);
+ }
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ static void __iomem *scu_base = IOMEM(VA_SCU_BASE);
+ 
+@@ -47,8 +47,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static int spear13xx_boot_secondary(unsigned int cpu, struct task_struct *idle)
+@@ -59,7 +59,7 @@
+ 	 * set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * The secondary processor is waiting to be released from
+@@ -84,7 +84,7 @@
+ 	 * now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return pen_release != -1 ? -ENOSYS : 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-sti/platsmp.c linux-3.18.8/arch/arm/mach-sti/platsmp.c
+--- linux-3.18.8.orig/arch/arm/mach-sti/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-sti/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -34,7 +34,7 @@
+ 	sync_cache_w(&pen_release);
+ }
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ static void sti_secondary_init(unsigned int cpu)
+ {
+@@ -49,8 +49,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static int sti_boot_secondary(unsigned int cpu, struct task_struct *idle)
+@@ -61,7 +61,7 @@
+ 	 * set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * The secondary processor is waiting to be released from
+@@ -92,7 +92,7 @@
+ 	 * now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return pen_release != -1 ? -ENOSYS : 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mach-ux500/platsmp.c linux-3.18.8/arch/arm/mach-ux500/platsmp.c
+--- linux-3.18.8.orig/arch/arm/mach-ux500/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mach-ux500/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -51,7 +51,7 @@
+ 	return NULL;
+ }
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ static void ux500_secondary_init(unsigned int cpu)
+ {
+@@ -64,8 +64,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ static int ux500_boot_secondary(unsigned int cpu, struct task_struct *idle)
+@@ -76,7 +76,7 @@
+ 	 * set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * The secondary processor is waiting to be released from
+@@ -97,7 +97,7 @@
+ 	 * now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return pen_release != -1 ? -ENOSYS : 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mm/fault.c linux-3.18.8/arch/arm/mm/fault.c
+--- linux-3.18.8.orig/arch/arm/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -277,7 +277,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	if (user_mode(regs))
+@@ -431,6 +431,9 @@
+ 	if (addr < TASK_SIZE)
+ 		return do_page_fault(addr, fsr, regs);
+ 
++	if (interrupts_enabled(regs))
++		local_irq_enable();
++
+ 	if (user_mode(regs))
+ 		goto bad_area;
+ 
+@@ -498,6 +501,9 @@
+ static int
+ do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+ {
++	if (interrupts_enabled(regs))
++		local_irq_enable();
++
+ 	do_bad_area(addr, fsr, regs);
+ 	return 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm/mm/highmem.c linux-3.18.8/arch/arm/mm/highmem.c
+--- linux-3.18.8.orig/arch/arm/mm/highmem.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/mm/highmem.c	2015-03-03 08:05:17.000000000 +0100
+@@ -53,6 +53,7 @@
+ 
+ void *kmap_atomic(struct page *page)
+ {
++	pte_t pte = mk_pte(page, kmap_prot);
+ 	unsigned int idx;
+ 	unsigned long vaddr;
+ 	void *kmap;
+@@ -91,7 +92,10 @@
+ 	 * in place, so the contained TLB flush ensures the TLB is updated
+ 	 * with the new mapping.
+ 	 */
+-	set_fixmap_pte(idx, mk_pte(page, kmap_prot));
++#ifdef CONFIG_PREEMPT_RT_FULL
++	current->kmap_pte[type] = pte;
++#endif
++	set_fixmap_pte(idx, pte);
+ 
+ 	return (void *)vaddr;
+ }
+@@ -108,12 +112,15 @@
+ 
+ 		if (cache_is_vivt())
+ 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
++#ifdef CONFIG_PREEMPT_RT_FULL
++		current->kmap_pte[type] = __pte(0);
++#endif
+ #ifdef CONFIG_DEBUG_HIGHMEM
+ 		BUG_ON(vaddr != __fix_to_virt(idx));
+-		set_fixmap_pte(idx, __pte(0));
+ #else
+ 		(void) idx;  /* to kill a warning */
+ #endif
++		set_fixmap_pte(idx, __pte(0));
+ 		kmap_atomic_idx_pop();
+ 	} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
+ 		/* this address was obtained through kmap_high_get() */
+@@ -125,6 +132,7 @@
+ 
+ void *kmap_atomic_pfn(unsigned long pfn)
+ {
++	pte_t pte = pfn_pte(pfn, kmap_prot);
+ 	unsigned long vaddr;
+ 	int idx, type;
+ 	struct page *page = pfn_to_page(pfn);
+@@ -139,7 +147,10 @@
+ #ifdef CONFIG_DEBUG_HIGHMEM
+ 	BUG_ON(!pte_none(*(fixmap_page_table + idx)));
+ #endif
+-	set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
++#ifdef CONFIG_PREEMPT_RT_FULL
++	current->kmap_pte[type] = pte;
++#endif
++	set_fixmap_pte(idx, pte);
+ 
+ 	return (void *)vaddr;
+ }
+@@ -153,3 +164,28 @@
+ 
+ 	return pte_page(get_fixmap_pte(vaddr));
+ }
++
++#if defined CONFIG_PREEMPT_RT_FULL
++void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
++{
++	int i;
++
++	/*
++	 * Clear @prev's kmap_atomic mappings
++	 */
++	for (i = 0; i < prev_p->kmap_idx; i++) {
++		int idx = i + KM_TYPE_NR * smp_processor_id();
++
++		set_fixmap_pte(idx, __pte(0));
++	}
++	/*
++	 * Restore @next_p's kmap_atomic mappings
++	 */
++	for (i = 0; i < next_p->kmap_idx; i++) {
++		int idx = i + KM_TYPE_NR * smp_processor_id();
++
++		if (!pte_none(next_p->kmap_pte[i]))
++			set_fixmap_pte(idx, next_p->kmap_pte[i]);
++	}
++}
++#endif
+diff -Nur linux-3.18.8.orig/arch/arm/plat-versatile/platsmp.c linux-3.18.8/arch/arm/plat-versatile/platsmp.c
+--- linux-3.18.8.orig/arch/arm/plat-versatile/platsmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm/plat-versatile/platsmp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -30,7 +30,7 @@
+ 	sync_cache_w(&pen_release);
+ }
+ 
+-static DEFINE_SPINLOCK(boot_lock);
++static DEFINE_RAW_SPINLOCK(boot_lock);
+ 
+ void versatile_secondary_init(unsigned int cpu)
+ {
+@@ -43,8 +43,8 @@
+ 	/*
+ 	 * Synchronise with the boot thread.
+ 	 */
+-	spin_lock(&boot_lock);
+-	spin_unlock(&boot_lock);
++	raw_spin_lock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ }
+ 
+ int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle)
+@@ -55,7 +55,7 @@
+ 	 * Set synchronisation state between this boot processor
+ 	 * and the secondary one
+ 	 */
+-	spin_lock(&boot_lock);
++	raw_spin_lock(&boot_lock);
+ 
+ 	/*
+ 	 * This is really belt and braces; we hold unintended secondary
+@@ -85,7 +85,7 @@
+ 	 * now the secondary core is starting up let it run its
+ 	 * calibrations, then wait for it to finish
+ 	 */
+-	spin_unlock(&boot_lock);
++	raw_spin_unlock(&boot_lock);
+ 
+ 	return pen_release != -1 ? -ENOSYS : 0;
+ }
+diff -Nur linux-3.18.8.orig/arch/arm64/kernel/smp.c linux-3.18.8/arch/arm64/kernel/smp.c
+--- linux-3.18.8.orig/arch/arm64/kernel/smp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/arm64/kernel/smp.c	2015-03-03 08:05:17.000000000 +0100
+@@ -529,12 +529,14 @@
+ }
+ 
+ #ifdef CONFIG_IRQ_WORK
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void arch_irq_work_raise(void)
+ {
+ 	if (__smp_cross_call)
+ 		smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
+ }
+ #endif
++#endif
+ 
+ static DEFINE_RAW_SPINLOCK(stop_lock);
+ 
+diff -Nur linux-3.18.8.orig/arch/avr32/mm/fault.c linux-3.18.8/arch/avr32/mm/fault.c
+--- linux-3.18.8.orig/arch/avr32/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/avr32/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -81,7 +81,7 @@
+ 	 * If we're in an interrupt or have no user context, we must
+ 	 * not take the fault...
+ 	 */
+-	if (in_atomic() || !mm || regs->sr & SYSREG_BIT(GM))
++	if (!mm || regs->sr & SYSREG_BIT(GM) || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	local_irq_enable();
+diff -Nur linux-3.18.8.orig/arch/cris/mm/fault.c linux-3.18.8/arch/cris/mm/fault.c
+--- linux-3.18.8.orig/arch/cris/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/cris/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -113,7 +113,7 @@
+ 	 * user context, we must not take the fault.
+ 	 */
+ 
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	if (user_mode(regs))
+diff -Nur linux-3.18.8.orig/arch/frv/mm/fault.c linux-3.18.8/arch/frv/mm/fault.c
+--- linux-3.18.8.orig/arch/frv/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/frv/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -78,7 +78,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	if (user_mode(__frame))
+diff -Nur linux-3.18.8.orig/arch/ia64/mm/fault.c linux-3.18.8/arch/ia64/mm/fault.c
+--- linux-3.18.8.orig/arch/ia64/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/ia64/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -96,7 +96,7 @@
+ 	/*
+ 	 * If we're in an interrupt or have no user context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ #ifdef CONFIG_VIRTUAL_MEM_MAP
+diff -Nur linux-3.18.8.orig/arch/Kconfig linux-3.18.8/arch/Kconfig
+--- linux-3.18.8.orig/arch/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/Kconfig	2015-03-03 08:05:17.000000000 +0100
+@@ -6,6 +6,7 @@
+ 	tristate "OProfile system profiling"
+ 	depends on PROFILING
+ 	depends on HAVE_OPROFILE
++	depends on !PREEMPT_RT_FULL
+ 	select RING_BUFFER
+ 	select RING_BUFFER_ALLOW_SWAP
+ 	help
+diff -Nur linux-3.18.8.orig/arch/m32r/mm/fault.c linux-3.18.8/arch/m32r/mm/fault.c
+--- linux-3.18.8.orig/arch/m32r/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/m32r/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -114,7 +114,7 @@
+ 	 * If we're in an interrupt or have no user context or are running in an
+ 	 * atomic region then we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto bad_area_nosemaphore;
+ 
+ 	if (error_code & ACE_USERMODE)
+diff -Nur linux-3.18.8.orig/arch/m68k/mm/fault.c linux-3.18.8/arch/m68k/mm/fault.c
+--- linux-3.18.8.orig/arch/m68k/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/m68k/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -81,7 +81,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	if (user_mode(regs))
+diff -Nur linux-3.18.8.orig/arch/microblaze/mm/fault.c linux-3.18.8/arch/microblaze/mm/fault.c
+--- linux-3.18.8.orig/arch/microblaze/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/microblaze/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -107,7 +107,7 @@
+ 	if ((error_code & 0x13) == 0x13 || (error_code & 0x11) == 0x11)
+ 		is_write = 0;
+ 
+-	if (unlikely(in_atomic() || !mm)) {
++	if (unlikely(!mm || pagefault_disabled())) {
+ 		if (kernel_mode(regs))
+ 			goto bad_area_nosemaphore;
+ 
+diff -Nur linux-3.18.8.orig/arch/mips/Kconfig linux-3.18.8/arch/mips/Kconfig
+--- linux-3.18.8.orig/arch/mips/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/mips/Kconfig	2015-03-03 08:05:17.000000000 +0100
+@@ -2196,7 +2196,7 @@
+ #
+ config HIGHMEM
+ 	bool "High Memory Support"
+-	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA
++	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA && !PREEMPT_RT_FULL
+ 
+ config CPU_SUPPORTS_HIGHMEM
+ 	bool
+diff -Nur linux-3.18.8.orig/arch/mips/kernel/signal.c linux-3.18.8/arch/mips/kernel/signal.c
+--- linux-3.18.8.orig/arch/mips/kernel/signal.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/mips/kernel/signal.c	2015-03-03 08:05:17.000000000 +0100
+@@ -613,6 +613,7 @@
+ 	__u32 thread_info_flags)
+ {
+ 	local_irq_enable();
++	preempt_check_resched();
+ 
+ 	user_exit();
+ 
+diff -Nur linux-3.18.8.orig/arch/mips/mm/fault.c linux-3.18.8/arch/mips/mm/fault.c
+--- linux-3.18.8.orig/arch/mips/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/mips/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -89,7 +89,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto bad_area_nosemaphore;
+ 
+ 	if (user_mode(regs))
+diff -Nur linux-3.18.8.orig/arch/mips/mm/init.c linux-3.18.8/arch/mips/mm/init.c
+--- linux-3.18.8.orig/arch/mips/mm/init.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/mips/mm/init.c	2015-03-03 08:05:17.000000000 +0100
+@@ -90,7 +90,7 @@
+ 
+ 	BUG_ON(Page_dcache_dirty(page));
+ 
+-	pagefault_disable();
++	raw_pagefault_disable();
+ 	idx = (addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1);
+ 	idx += in_interrupt() ? FIX_N_COLOURS : 0;
+ 	vaddr = __fix_to_virt(FIX_CMAP_END - idx);
+@@ -146,7 +146,7 @@
+ 	tlbw_use_hazard();
+ 	write_c0_entryhi(old_ctx);
+ 	local_irq_restore(flags);
+-	pagefault_enable();
++	raw_pagefault_enable();
+ }
+ 
+ void copy_user_highpage(struct page *to, struct page *from,
+diff -Nur linux-3.18.8.orig/arch/mn10300/mm/fault.c linux-3.18.8/arch/mn10300/mm/fault.c
+--- linux-3.18.8.orig/arch/mn10300/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/mn10300/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -168,7 +168,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
+diff -Nur linux-3.18.8.orig/arch/parisc/mm/fault.c linux-3.18.8/arch/parisc/mm/fault.c
+--- linux-3.18.8.orig/arch/parisc/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/parisc/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -207,7 +207,7 @@
+ 	int fault;
+ 	unsigned int flags;
+ 
+-	if (in_atomic())
++	if (pagefault_disabled())
+ 		goto no_context;
+ 
+ 	tsk = current;
+diff -Nur linux-3.18.8.orig/arch/powerpc/include/asm/thread_info.h linux-3.18.8/arch/powerpc/include/asm/thread_info.h
+--- linux-3.18.8.orig/arch/powerpc/include/asm/thread_info.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/include/asm/thread_info.h	2015-03-03 08:05:17.000000000 +0100
+@@ -43,6 +43,8 @@
+ 	int		cpu;			/* cpu we're on */
+ 	int		preempt_count;		/* 0 => preemptable,
+ 						   <0 => BUG */
++	int		preempt_lazy_count;	/* 0 => preemptable,
++						   <0 => BUG */
+ 	struct restart_block restart_block;
+ 	unsigned long	local_flags;		/* private flags for thread */
+ 
+@@ -88,8 +90,7 @@
+ #define TIF_SYSCALL_TRACE	0	/* syscall trace active */
+ #define TIF_SIGPENDING		1	/* signal pending */
+ #define TIF_NEED_RESCHED	2	/* rescheduling necessary */
+-#define TIF_POLLING_NRFLAG	3	/* true if poll_idle() is polling
+-					   TIF_NEED_RESCHED */
++#define TIF_NEED_RESCHED_LAZY	3	/* lazy rescheduling necessary */
+ #define TIF_32BIT		4	/* 32 bit binary */
+ #define TIF_RESTORE_TM		5	/* need to restore TM FP/VEC/VSX */
+ #define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
+@@ -107,6 +108,8 @@
+ #if defined(CONFIG_PPC64)
+ #define TIF_ELF2ABI		18	/* function descriptors must die! */
+ #endif
++#define TIF_POLLING_NRFLAG	19	/* true if poll_idle() is polling
++					   TIF_NEED_RESCHED */
+ 
+ /* as above, but as bit values */
+ #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
+@@ -125,14 +128,16 @@
+ #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
+ #define _TIF_EMULATE_STACK_STORE	(1<<TIF_EMULATE_STACK_STORE)
+ #define _TIF_NOHZ		(1<<TIF_NOHZ)
++#define _TIF_NEED_RESCHED_LAZY	(1<<TIF_NEED_RESCHED_LAZY)
+ #define _TIF_SYSCALL_T_OR_A	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
+ 				 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
+ 				 _TIF_NOHZ)
+ 
+ #define _TIF_USER_WORK_MASK	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
+ 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
+-				 _TIF_RESTORE_TM)
++				 _TIF_RESTORE_TM | _TIF_NEED_RESCHED_LAZY)
+ #define _TIF_PERSYSCALL_MASK	(_TIF_RESTOREALL|_TIF_NOERROR)
++#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
+ 
+ /* Bits in local_flags */
+ /* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
+diff -Nur linux-3.18.8.orig/arch/powerpc/Kconfig linux-3.18.8/arch/powerpc/Kconfig
+--- linux-3.18.8.orig/arch/powerpc/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/Kconfig	2015-03-03 08:05:17.000000000 +0100
+@@ -60,10 +60,11 @@
+ 
+ config RWSEM_GENERIC_SPINLOCK
+ 	bool
++	default y if PREEMPT_RT_FULL
+ 
+ config RWSEM_XCHGADD_ALGORITHM
+ 	bool
+-	default y
++	default y if !PREEMPT_RT_FULL
+ 
+ config GENERIC_LOCKBREAK
+ 	bool
+@@ -136,6 +137,7 @@
+ 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
+ 	select GENERIC_STRNCPY_FROM_USER
+ 	select GENERIC_STRNLEN_USER
++	select HAVE_PREEMPT_LAZY
+ 	select HAVE_MOD_ARCH_SPECIFIC
+ 	select MODULES_USE_ELF_RELA
+ 	select CLONE_BACKWARDS
+@@ -303,7 +305,7 @@
+ 
+ config HIGHMEM
+ 	bool "High memory support"
+-	depends on PPC32
++	depends on PPC32 && !PREEMPT_RT_FULL
+ 
+ source kernel/Kconfig.hz
+ source kernel/Kconfig.preempt
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/asm-offsets.c linux-3.18.8/arch/powerpc/kernel/asm-offsets.c
+--- linux-3.18.8.orig/arch/powerpc/kernel/asm-offsets.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/asm-offsets.c	2015-03-03 08:05:17.000000000 +0100
+@@ -159,6 +159,7 @@
+ 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
+ 	DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
+ 	DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count));
++	DEFINE(TI_PREEMPT_LAZY, offsetof(struct thread_info, preempt_lazy_count));
+ 	DEFINE(TI_TASK, offsetof(struct thread_info, task));
+ 	DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
+ 
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/entry_32.S linux-3.18.8/arch/powerpc/kernel/entry_32.S
+--- linux-3.18.8.orig/arch/powerpc/kernel/entry_32.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/entry_32.S	2015-03-03 08:05:17.000000000 +0100
+@@ -890,7 +890,14 @@
+ 	cmpwi	0,r0,0		/* if non-zero, just restore regs and return */
+ 	bne	restore
+ 	andi.	r8,r8,_TIF_NEED_RESCHED
++	bne+	1f
++	lwz	r0,TI_PREEMPT_LAZY(r9)
++	cmpwi	0,r0,0		/* if non-zero, just restore regs and return */
++	bne	restore
++	lwz	r0,TI_FLAGS(r9)
++	andi.	r0,r0,_TIF_NEED_RESCHED_LAZY
+ 	beq+	restore
++1:
+ 	lwz	r3,_MSR(r1)
+ 	andi.	r0,r3,MSR_EE	/* interrupts off? */
+ 	beq	restore		/* don't schedule if so */
+@@ -901,11 +908,11 @@
+ 	 */
+ 	bl	trace_hardirqs_off
+ #endif
+-1:	bl	preempt_schedule_irq
++2:	bl	preempt_schedule_irq
+ 	CURRENT_THREAD_INFO(r9, r1)
+ 	lwz	r3,TI_FLAGS(r9)
+-	andi.	r0,r3,_TIF_NEED_RESCHED
+-	bne-	1b
++	andi.	r0,r3,_TIF_NEED_RESCHED_MASK
++	bne-	2b
+ #ifdef CONFIG_TRACE_IRQFLAGS
+ 	/* And now, to properly rebalance the above, we tell lockdep they
+ 	 * are being turned back on, which will happen when we return
+@@ -1226,7 +1233,7 @@
+ #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
+ 
+ do_work:			/* r10 contains MSR_KERNEL here */
+-	andi.	r0,r9,_TIF_NEED_RESCHED
++	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
+ 	beq	do_user_signal
+ 
+ do_resched:			/* r10 contains MSR_KERNEL here */
+@@ -1247,7 +1254,7 @@
+ 	MTMSRD(r10)		/* disable interrupts */
+ 	CURRENT_THREAD_INFO(r9, r1)
+ 	lwz	r9,TI_FLAGS(r9)
+-	andi.	r0,r9,_TIF_NEED_RESCHED
++	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
+ 	bne-	do_resched
+ 	andi.	r0,r9,_TIF_USER_WORK_MASK
+ 	beq	restore_user
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/entry_64.S linux-3.18.8/arch/powerpc/kernel/entry_64.S
+--- linux-3.18.8.orig/arch/powerpc/kernel/entry_64.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/entry_64.S	2015-03-03 08:05:17.000000000 +0100
+@@ -644,7 +644,7 @@
+ #else
+ 	beq	restore
+ #endif
+-1:	andi.	r0,r4,_TIF_NEED_RESCHED
++1:	andi.	r0,r4,_TIF_NEED_RESCHED_MASK
+ 	beq	2f
+ 	bl	restore_interrupts
+ 	SCHEDULE_USER
+@@ -706,10 +706,18 @@
+ 
+ #ifdef CONFIG_PREEMPT
+ 	/* Check if we need to preempt */
++	lwz	r8,TI_PREEMPT(r9)
++	cmpwi	0,r8,0		/* if non-zero, just restore regs and return */
++	bne	restore
+ 	andi.	r0,r4,_TIF_NEED_RESCHED
++	bne+	check_count
++
++	andi.	r0,r4,_TIF_NEED_RESCHED_LAZY
+ 	beq+	restore
++	lwz	r8,TI_PREEMPT_LAZY(r9)
++
+ 	/* Check that preempt_count() == 0 and interrupts are enabled */
+-	lwz	r8,TI_PREEMPT(r9)
++check_count:
+ 	cmpwi	cr1,r8,0
+ 	ld	r0,SOFTE(r1)
+ 	cmpdi	r0,0
+@@ -726,7 +734,7 @@
+ 	/* Re-test flags and eventually loop */
+ 	CURRENT_THREAD_INFO(r9, r1)
+ 	ld	r4,TI_FLAGS(r9)
+-	andi.	r0,r4,_TIF_NEED_RESCHED
++	andi.	r0,r4,_TIF_NEED_RESCHED_MASK
+ 	bne	1b
+ 
+ 	/*
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/irq.c linux-3.18.8/arch/powerpc/kernel/irq.c
+--- linux-3.18.8.orig/arch/powerpc/kernel/irq.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/irq.c	2015-03-03 08:05:17.000000000 +0100
+@@ -615,6 +615,7 @@
+ 	}
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void do_softirq_own_stack(void)
+ {
+ 	struct thread_info *curtp, *irqtp;
+@@ -632,6 +633,7 @@
+ 	if (irqtp->flags)
+ 		set_bits(irqtp->flags, &curtp->flags);
+ }
++#endif
+ 
+ irq_hw_number_t virq_to_hw(unsigned int virq)
+ {
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/misc_32.S linux-3.18.8/arch/powerpc/kernel/misc_32.S
+--- linux-3.18.8.orig/arch/powerpc/kernel/misc_32.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/misc_32.S	2015-03-03 08:05:17.000000000 +0100
+@@ -40,6 +40,7 @@
+  * We store the saved ksp_limit in the unused part
+  * of the STACK_FRAME_OVERHEAD
+  */
++#ifndef CONFIG_PREEMPT_RT_FULL
+ _GLOBAL(call_do_softirq)
+ 	mflr	r0
+ 	stw	r0,4(r1)
+@@ -56,6 +57,7 @@
+ 	stw	r10,THREAD+KSP_LIMIT(r2)
+ 	mtlr	r0
+ 	blr
++#endif
+ 
+ /*
+  * void call_do_irq(struct pt_regs *regs, struct thread_info *irqtp);
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/misc_64.S linux-3.18.8/arch/powerpc/kernel/misc_64.S
+--- linux-3.18.8.orig/arch/powerpc/kernel/misc_64.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/misc_64.S	2015-03-03 08:05:17.000000000 +0100
+@@ -29,6 +29,7 @@
+ 
+ 	.text
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ _GLOBAL(call_do_softirq)
+ 	mflr	r0
+ 	std	r0,16(r1)
+@@ -39,6 +40,7 @@
+ 	ld	r0,16(r1)
+ 	mtlr	r0
+ 	blr
++#endif
+ 
+ _GLOBAL(call_do_irq)
+ 	mflr	r0
+diff -Nur linux-3.18.8.orig/arch/powerpc/kernel/time.c linux-3.18.8/arch/powerpc/kernel/time.c
+--- linux-3.18.8.orig/arch/powerpc/kernel/time.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/kernel/time.c	2015-03-03 08:05:17.000000000 +0100
+@@ -424,7 +424,7 @@
+ EXPORT_SYMBOL(profile_pc);
+ #endif
+ 
+-#ifdef CONFIG_IRQ_WORK
++#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL)
+ 
+ /*
+  * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable...
+diff -Nur linux-3.18.8.orig/arch/powerpc/mm/fault.c linux-3.18.8/arch/powerpc/mm/fault.c
+--- linux-3.18.8.orig/arch/powerpc/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/powerpc/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -273,7 +273,7 @@
+ 	if (!arch_irq_disabled_regs(regs))
+ 		local_irq_enable();
+ 
+-	if (in_atomic() || mm == NULL) {
++	if (in_atomic() || mm == NULL || pagefault_disabled()) {
+ 		if (!user_mode(regs)) {
+ 			rc = SIGSEGV;
+ 			goto bail;
+diff -Nur linux-3.18.8.orig/arch/s390/mm/fault.c linux-3.18.8/arch/s390/mm/fault.c
+--- linux-3.18.8.orig/arch/s390/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/s390/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -435,7 +435,8 @@
+ 	 * user context.
+ 	 */
+ 	fault = VM_FAULT_BADCONTEXT;
+-	if (unlikely(!user_space_fault(regs) || in_atomic() || !mm))
++	if (unlikely(!user_space_fault(regs) || !mm ||
++		     tsk->pagefault_disabled))
+ 		goto out;
+ 
+ 	address = trans_exc_code & __FAIL_ADDR_MASK;
+diff -Nur linux-3.18.8.orig/arch/score/mm/fault.c linux-3.18.8/arch/score/mm/fault.c
+--- linux-3.18.8.orig/arch/score/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/score/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -73,7 +73,7 @@
+ 	* If we're in an interrupt or have no user
+ 	* context, we must not take the fault..
+ 	*/
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto bad_area_nosemaphore;
+ 
+ 	if (user_mode(regs))
+diff -Nur linux-3.18.8.orig/arch/sh/kernel/irq.c linux-3.18.8/arch/sh/kernel/irq.c
+--- linux-3.18.8.orig/arch/sh/kernel/irq.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sh/kernel/irq.c	2015-03-03 08:05:17.000000000 +0100
+@@ -149,6 +149,7 @@
+ 	hardirq_ctx[cpu] = NULL;
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void do_softirq_own_stack(void)
+ {
+ 	struct thread_info *curctx;
+@@ -176,6 +177,7 @@
+ 		  "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
+ 	);
+ }
++#endif
+ #else
+ static inline void handle_one_irq(unsigned int irq)
+ {
+diff -Nur linux-3.18.8.orig/arch/sh/mm/fault.c linux-3.18.8/arch/sh/mm/fault.c
+--- linux-3.18.8.orig/arch/sh/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sh/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -440,7 +440,7 @@
+ 	 * If we're in an interrupt, have no user context or are running
+ 	 * in an atomic region then we must not take the fault:
+ 	 */
+-	if (unlikely(in_atomic() || !mm)) {
++	if (unlikely(!mm || pagefault_disabled())) {
+ 		bad_area_nosemaphore(regs, error_code, address);
+ 		return;
+ 	}
+diff -Nur linux-3.18.8.orig/arch/sparc/Kconfig linux-3.18.8/arch/sparc/Kconfig
+--- linux-3.18.8.orig/arch/sparc/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/Kconfig	2015-03-03 08:05:17.000000000 +0100
+@@ -182,12 +182,10 @@
+ source kernel/Kconfig.hz
+ 
+ config RWSEM_GENERIC_SPINLOCK
+-	bool
+-	default y if SPARC32
++	def_bool PREEMPT_RT_FULL
+ 
+ config RWSEM_XCHGADD_ALGORITHM
+-	bool
+-	default y if SPARC64
++	def_bool !RWSEM_GENERIC_SPINLOCK && !PREEMPT_RT_FULL
+ 
+ config GENERIC_HWEIGHT
+ 	bool
+@@ -528,6 +526,10 @@
+ 
+ source "fs/Kconfig.binfmt"
+ 
++config EARLY_PRINTK
++	bool
++	default y
++
+ config COMPAT
+ 	bool
+ 	depends on SPARC64
+diff -Nur linux-3.18.8.orig/arch/sparc/kernel/irq_64.c linux-3.18.8/arch/sparc/kernel/irq_64.c
+--- linux-3.18.8.orig/arch/sparc/kernel/irq_64.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/kernel/irq_64.c	2015-03-03 08:05:17.000000000 +0100
+@@ -849,6 +849,7 @@
+ 	set_irq_regs(old_regs);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void do_softirq_own_stack(void)
+ {
+ 	void *orig_sp, *sp = softirq_stack[smp_processor_id()];
+@@ -863,6 +864,7 @@
+ 	__asm__ __volatile__("mov %0, %%sp"
+ 			     : : "r" (orig_sp));
+ }
++#endif
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+ void fixup_irqs(void)
+diff -Nur linux-3.18.8.orig/arch/sparc/kernel/pcr.c linux-3.18.8/arch/sparc/kernel/pcr.c
+--- linux-3.18.8.orig/arch/sparc/kernel/pcr.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/kernel/pcr.c	2015-03-03 08:05:17.000000000 +0100
+@@ -43,10 +43,12 @@
+ 	set_irq_regs(old_regs);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void arch_irq_work_raise(void)
+ {
+ 	set_softint(1 << PIL_DEFERRED_PCR_WORK);
+ }
++#endif
+ 
+ const struct pcr_ops *pcr_ops;
+ EXPORT_SYMBOL_GPL(pcr_ops);
+diff -Nur linux-3.18.8.orig/arch/sparc/kernel/setup_32.c linux-3.18.8/arch/sparc/kernel/setup_32.c
+--- linux-3.18.8.orig/arch/sparc/kernel/setup_32.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/kernel/setup_32.c	2015-03-03 08:05:17.000000000 +0100
+@@ -309,6 +309,7 @@
+ 
+ 	boot_flags_init(*cmdline_p);
+ 
++	early_console = &prom_early_console;
+ 	register_console(&prom_early_console);
+ 
+ 	printk("ARCH: ");
+diff -Nur linux-3.18.8.orig/arch/sparc/kernel/setup_64.c linux-3.18.8/arch/sparc/kernel/setup_64.c
+--- linux-3.18.8.orig/arch/sparc/kernel/setup_64.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/kernel/setup_64.c	2015-03-03 08:05:17.000000000 +0100
+@@ -563,6 +563,12 @@
+ 		pause_patch();
+ }
+ 
++static inline void register_prom_console(void)
++{
++	early_console = &prom_early_console;
++	register_console(&prom_early_console);
++}
++
+ void __init setup_arch(char **cmdline_p)
+ {
+ 	/* Initialize PROM console and command line. */
+@@ -574,7 +580,7 @@
+ #ifdef CONFIG_EARLYFB
+ 	if (btext_find_display())
+ #endif
+-		register_console(&prom_early_console);
++		register_prom_console();
+ 
+ 	if (tlb_type == hypervisor)
+ 		printk("ARCH: SUN4V\n");
+diff -Nur linux-3.18.8.orig/arch/sparc/mm/fault_32.c linux-3.18.8/arch/sparc/mm/fault_32.c
+--- linux-3.18.8.orig/arch/sparc/mm/fault_32.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/mm/fault_32.c	2015-03-03 08:05:17.000000000 +0100
+@@ -196,7 +196,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto no_context;
+ 
+ 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+diff -Nur linux-3.18.8.orig/arch/sparc/mm/fault_64.c linux-3.18.8/arch/sparc/mm/fault_64.c
+--- linux-3.18.8.orig/arch/sparc/mm/fault_64.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/sparc/mm/fault_64.c	2015-03-03 08:05:17.000000000 +0100
+@@ -330,7 +330,7 @@
+ 	 * If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm)
++	if (!mm || pagefault_disabled())
+ 		goto intr_or_no_mm;
+ 
+ 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+diff -Nur linux-3.18.8.orig/arch/tile/mm/fault.c linux-3.18.8/arch/tile/mm/fault.c
+--- linux-3.18.8.orig/arch/tile/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/tile/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -357,7 +357,7 @@
+ 	 * If we're in an interrupt, have no user context or are running in an
+ 	 * atomic region then we must not take the fault.
+ 	 */
+-	if (in_atomic() || !mm) {
++	if (!mm || pagefault_disabled()) {
+ 		vma = NULL;  /* happy compiler */
+ 		goto bad_area_nosemaphore;
+ 	}
+diff -Nur linux-3.18.8.orig/arch/um/kernel/trap.c linux-3.18.8/arch/um/kernel/trap.c
+--- linux-3.18.8.orig/arch/um/kernel/trap.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/um/kernel/trap.c	2015-03-03 08:05:17.000000000 +0100
+@@ -38,7 +38,7 @@
+ 	 * If the fault was during atomic operation, don't take the fault, just
+ 	 * fail.
+ 	 */
+-	if (in_atomic())
++	if (pagefault_disabled())
+ 		goto out_nosemaphore;
+ 
+ 	if (is_user)
+diff -Nur linux-3.18.8.orig/arch/x86/crypto/aesni-intel_glue.c linux-3.18.8/arch/x86/crypto/aesni-intel_glue.c
+--- linux-3.18.8.orig/arch/x86/crypto/aesni-intel_glue.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/crypto/aesni-intel_glue.c	2015-03-03 08:05:17.000000000 +0100
+@@ -381,14 +381,14 @@
+ 	err = blkcipher_walk_virt(desc, &walk);
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_ecb_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+-			      nbytes & AES_BLOCK_MASK);
++				nbytes & AES_BLOCK_MASK);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -405,14 +405,14 @@
+ 	err = blkcipher_walk_virt(desc, &walk);
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_ecb_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -429,14 +429,14 @@
+ 	err = blkcipher_walk_virt(desc, &walk);
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_cbc_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK, walk.iv);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -453,14 +453,14 @@
+ 	err = blkcipher_walk_virt(desc, &walk);
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_cbc_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK, walk.iv);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -512,18 +512,20 @@
+ 	err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
++		kernel_fpu_begin();
+ 		aesni_ctr_enc_tfm(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 				  nbytes & AES_BLOCK_MASK, walk.iv);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+ 	if (walk.nbytes) {
++		kernel_fpu_begin();
+ 		ctr_crypt_final(ctx, &walk);
++		kernel_fpu_end();
+ 		err = blkcipher_walk_done(desc, &walk, 0);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+diff -Nur linux-3.18.8.orig/arch/x86/crypto/cast5_avx_glue.c linux-3.18.8/arch/x86/crypto/cast5_avx_glue.c
+--- linux-3.18.8.orig/arch/x86/crypto/cast5_avx_glue.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/crypto/cast5_avx_glue.c	2015-03-03 08:05:17.000000000 +0100
+@@ -60,7 +60,7 @@
+ static int ecb_crypt(struct blkcipher_desc *desc, struct blkcipher_walk *walk,
+ 		     bool enc)
+ {
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct cast5_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+ 	const unsigned int bsize = CAST5_BLOCK_SIZE;
+ 	unsigned int nbytes;
+@@ -76,7 +76,7 @@
+ 		u8 *wsrc = walk->src.virt.addr;
+ 		u8 *wdst = walk->dst.virt.addr;
+ 
+-		fpu_enabled = cast5_fpu_begin(fpu_enabled, nbytes);
++		fpu_enabled = cast5_fpu_begin(false, nbytes);
+ 
+ 		/* Process multi-block batch */
+ 		if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
+@@ -104,10 +104,9 @@
+ 		} while (nbytes >= bsize);
+ 
+ done:
++		cast5_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, walk, nbytes);
+ 	}
+-
+-	cast5_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ 
+@@ -228,7 +227,7 @@
+ static int cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+ 		       struct scatterlist *src, unsigned int nbytes)
+ {
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct blkcipher_walk walk;
+ 	int err;
+ 
+@@ -237,12 +236,11 @@
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+ 	while ((nbytes = walk.nbytes)) {
+-		fpu_enabled = cast5_fpu_begin(fpu_enabled, nbytes);
++		fpu_enabled = cast5_fpu_begin(false, nbytes);
+ 		nbytes = __cbc_decrypt(desc, &walk);
++		cast5_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+-
+-	cast5_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ 
+@@ -312,7 +310,7 @@
+ static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+ 		     struct scatterlist *src, unsigned int nbytes)
+ {
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct blkcipher_walk walk;
+ 	int err;
+ 
+@@ -321,13 +319,12 @@
+ 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+ 
+ 	while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {
+-		fpu_enabled = cast5_fpu_begin(fpu_enabled, nbytes);
++		fpu_enabled = cast5_fpu_begin(false, nbytes);
+ 		nbytes = __ctr_crypt(desc, &walk);
++		cast5_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+ 
+-	cast5_fpu_end(fpu_enabled);
+-
+ 	if (walk.nbytes) {
+ 		ctr_crypt_final(desc, &walk);
+ 		err = blkcipher_walk_done(desc, &walk, 0);
+diff -Nur linux-3.18.8.orig/arch/x86/crypto/glue_helper.c linux-3.18.8/arch/x86/crypto/glue_helper.c
+--- linux-3.18.8.orig/arch/x86/crypto/glue_helper.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/crypto/glue_helper.c	2015-03-03 08:05:17.000000000 +0100
+@@ -39,7 +39,7 @@
+ 	void *ctx = crypto_blkcipher_ctx(desc->tfm);
+ 	const unsigned int bsize = 128 / 8;
+ 	unsigned int nbytes, i, func_bytes;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	int err;
+ 
+ 	err = blkcipher_walk_virt(desc, walk);
+@@ -49,7 +49,7 @@
+ 		u8 *wdst = walk->dst.virt.addr;
+ 
+ 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-					     desc, fpu_enabled, nbytes);
++					     desc, false, nbytes);
+ 
+ 		for (i = 0; i < gctx->num_funcs; i++) {
+ 			func_bytes = bsize * gctx->funcs[i].num_blocks;
+@@ -71,10 +71,10 @@
+ 		}
+ 
+ done:
++		glue_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, walk, nbytes);
+ 	}
+ 
+-	glue_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ 
+@@ -194,7 +194,7 @@
+ 			    struct scatterlist *src, unsigned int nbytes)
+ {
+ 	const unsigned int bsize = 128 / 8;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct blkcipher_walk walk;
+ 	int err;
+ 
+@@ -203,12 +203,12 @@
+ 
+ 	while ((nbytes = walk.nbytes)) {
+ 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-					     desc, fpu_enabled, nbytes);
++					     desc, false, nbytes);
+ 		nbytes = __glue_cbc_decrypt_128bit(gctx, desc, &walk);
++		glue_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+ 
+-	glue_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ EXPORT_SYMBOL_GPL(glue_cbc_decrypt_128bit);
+@@ -278,7 +278,7 @@
+ 			  struct scatterlist *src, unsigned int nbytes)
+ {
+ 	const unsigned int bsize = 128 / 8;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct blkcipher_walk walk;
+ 	int err;
+ 
+@@ -287,13 +287,12 @@
+ 
+ 	while ((nbytes = walk.nbytes) >= bsize) {
+ 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-					     desc, fpu_enabled, nbytes);
++					     desc, false, nbytes);
+ 		nbytes = __glue_ctr_crypt_128bit(gctx, desc, &walk);
++		glue_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 	}
+ 
+-	glue_fpu_end(fpu_enabled);
+-
+ 	if (walk.nbytes) {
+ 		glue_ctr_crypt_final_128bit(
+ 			gctx->funcs[gctx->num_funcs - 1].fn_u.ctr, desc, &walk);
+@@ -348,7 +347,7 @@
+ 			  void *tweak_ctx, void *crypt_ctx)
+ {
+ 	const unsigned int bsize = 128 / 8;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct blkcipher_walk walk;
+ 	int err;
+ 
+@@ -361,21 +360,21 @@
+ 
+ 	/* set minimum length to bsize, for tweak_fn */
+ 	fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-				     desc, fpu_enabled,
++				     desc, false,
+ 				     nbytes < bsize ? bsize : nbytes);
+-
+ 	/* calculate first value of T */
+ 	tweak_fn(tweak_ctx, walk.iv, walk.iv);
++	glue_fpu_end(fpu_enabled);
+ 
+ 	while (nbytes) {
++		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
++				desc, false, nbytes);
+ 		nbytes = __glue_xts_crypt_128bit(gctx, crypt_ctx, desc, &walk);
+ 
++		glue_fpu_end(fpu_enabled);
+ 		err = blkcipher_walk_done(desc, &walk, nbytes);
+ 		nbytes = walk.nbytes;
+ 	}
+-
+-	glue_fpu_end(fpu_enabled);
+-
+ 	return err;
+ }
+ EXPORT_SYMBOL_GPL(glue_xts_crypt_128bit);
+diff -Nur linux-3.18.8.orig/arch/x86/include/asm/preempt.h linux-3.18.8/arch/x86/include/asm/preempt.h
+--- linux-3.18.8.orig/arch/x86/include/asm/preempt.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/include/asm/preempt.h	2015-03-03 08:05:17.000000000 +0100
+@@ -85,17 +85,33 @@
+  * a decrement which hits zero means we have no preempt_count and should
+  * reschedule.
+  */
+-static __always_inline bool __preempt_count_dec_and_test(void)
++static __always_inline bool ____preempt_count_dec_and_test(void)
+ {
+ 	GEN_UNARY_RMWcc("decl", __preempt_count, __percpu_arg(0), "e");
+ }
+ 
++static __always_inline bool __preempt_count_dec_and_test(void)
++{
++	if (____preempt_count_dec_and_test())
++		return true;
++#ifdef CONFIG_PREEMPT_LAZY
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++#else
++	return false;
++#endif
++}
++
+ /*
+  * Returns true when we need to resched and can (barring IRQ state).
+  */
+ static __always_inline bool should_resched(void)
+ {
++#ifdef CONFIG_PREEMPT_LAZY
++	return unlikely(!raw_cpu_read_4(__preempt_count) || \
++			test_thread_flag(TIF_NEED_RESCHED_LAZY));
++#else
+ 	return unlikely(!raw_cpu_read_4(__preempt_count));
++#endif
+ }
+ 
+ #ifdef CONFIG_PREEMPT
+diff -Nur linux-3.18.8.orig/arch/x86/include/asm/signal.h linux-3.18.8/arch/x86/include/asm/signal.h
+--- linux-3.18.8.orig/arch/x86/include/asm/signal.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/include/asm/signal.h	2015-03-03 08:05:17.000000000 +0100
+@@ -23,6 +23,19 @@
+ 	unsigned long sig[_NSIG_WORDS];
+ } sigset_t;
+ 
++/*
++ * Because some traps use the IST stack, we must keep preemption
++ * disabled while calling do_trap(), but do_trap() may call
++ * force_sig_info() which will grab the signal spin_locks for the
++ * task, which in PREEMPT_RT_FULL are mutexes.  By defining
++ * ARCH_RT_DELAYS_SIGNAL_SEND the force_sig_info() will set
++ * TIF_NOTIFY_RESUME and set up the signal to be sent on exit of the
++ * trap.
++ */
++#if defined(CONFIG_PREEMPT_RT_FULL) && defined(CONFIG_X86_64)
++#define ARCH_RT_DELAYS_SIGNAL_SEND
++#endif
++
+ #ifndef CONFIG_COMPAT
+ typedef sigset_t compat_sigset_t;
+ #endif
+diff -Nur linux-3.18.8.orig/arch/x86/include/asm/stackprotector.h linux-3.18.8/arch/x86/include/asm/stackprotector.h
+--- linux-3.18.8.orig/arch/x86/include/asm/stackprotector.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/include/asm/stackprotector.h	2015-03-03 08:05:17.000000000 +0100
+@@ -57,7 +57,7 @@
+  */
+ static __always_inline void boot_init_stack_canary(void)
+ {
+-	u64 canary;
++	u64 uninitialized_var(canary);
+ 	u64 tsc;
+ 
+ #ifdef CONFIG_X86_64
+@@ -68,8 +68,16 @@
+ 	 * of randomness. The TSC only matters for very early init,
+ 	 * there it already has some randomness on most systems. Later
+ 	 * on during the bootup the random pool has true entropy too.
++	 *
++	 * For preempt-rt we need to weaken the randomness a bit, as
++	 * we can't call into the random generator from atomic context
++	 * due to locking constraints. We just leave canary
++	 * uninitialized and use the TSC based randomness on top of
++	 * it.
+ 	 */
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	get_random_bytes(&canary, sizeof(canary));
++#endif
+ 	tsc = __native_read_tsc();
+ 	canary += tsc + (tsc << 32UL);
+ 
+diff -Nur linux-3.18.8.orig/arch/x86/include/asm/thread_info.h linux-3.18.8/arch/x86/include/asm/thread_info.h
+--- linux-3.18.8.orig/arch/x86/include/asm/thread_info.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/include/asm/thread_info.h	2015-03-03 08:05:17.000000000 +0100
+@@ -30,6 +30,8 @@
+ 	__u32			status;		/* thread synchronous flags */
+ 	__u32			cpu;		/* current CPU */
+ 	int			saved_preempt_count;
++	int			preempt_lazy_count;	/* 0 => lazy preemptable
++							   <0 => BUG */
+ 	mm_segment_t		addr_limit;
+ 	struct restart_block    restart_block;
+ 	void __user		*sysenter_return;
+@@ -75,6 +77,7 @@
+ #define TIF_SYSCALL_EMU		6	/* syscall emulation active */
+ #define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
+ #define TIF_SECCOMP		8	/* secure computing */
++#define TIF_NEED_RESCHED_LAZY	9	/* lazy rescheduling necessary */
+ #define TIF_MCE_NOTIFY		10	/* notify userspace of an MCE */
+ #define TIF_USER_RETURN_NOTIFY	11	/* notify kernel of userspace return */
+ #define TIF_UPROBE		12	/* breakpointed or singlestepping */
+@@ -100,6 +103,7 @@
+ #define _TIF_SYSCALL_EMU	(1 << TIF_SYSCALL_EMU)
+ #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
+ #define _TIF_SECCOMP		(1 << TIF_SECCOMP)
++#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
+ #define _TIF_MCE_NOTIFY		(1 << TIF_MCE_NOTIFY)
+ #define _TIF_USER_RETURN_NOTIFY	(1 << TIF_USER_RETURN_NOTIFY)
+ #define _TIF_UPROBE		(1 << TIF_UPROBE)
+@@ -150,6 +154,8 @@
+ #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
+ #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
+ 
++#define _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
++
+ #define STACK_WARN		(THREAD_SIZE/8)
+ #define KERNEL_STACK_OFFSET	(5*(BITS_PER_LONG/8))
+ 
+diff -Nur linux-3.18.8.orig/arch/x86/include/asm/uv/uv_bau.h linux-3.18.8/arch/x86/include/asm/uv/uv_bau.h
+--- linux-3.18.8.orig/arch/x86/include/asm/uv/uv_bau.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/include/asm/uv/uv_bau.h	2015-03-03 08:05:17.000000000 +0100
+@@ -615,9 +615,9 @@
+ 	cycles_t		send_message;
+ 	cycles_t		period_end;
+ 	cycles_t		period_time;
+-	spinlock_t		uvhub_lock;
+-	spinlock_t		queue_lock;
+-	spinlock_t		disable_lock;
++	raw_spinlock_t		uvhub_lock;
++	raw_spinlock_t		queue_lock;
++	raw_spinlock_t		disable_lock;
+ 	/* tunables */
+ 	int			max_concurr;
+ 	int			max_concurr_const;
+@@ -776,15 +776,15 @@
+  * to be lowered below the current 'v'.  atomic_add_unless can only stop
+  * on equal.
+  */
+-static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
++static inline int atomic_inc_unless_ge(raw_spinlock_t *lock, atomic_t *v, int u)
+ {
+-	spin_lock(lock);
++	raw_spin_lock(lock);
+ 	if (atomic_read(v) >= u) {
+-		spin_unlock(lock);
++		raw_spin_unlock(lock);
+ 		return 0;
+ 	}
+ 	atomic_inc(v);
+-	spin_unlock(lock);
++	raw_spin_unlock(lock);
+ 	return 1;
+ }
+ 
+diff -Nur linux-3.18.8.orig/arch/x86/include/asm/uv/uv_hub.h linux-3.18.8/arch/x86/include/asm/uv/uv_hub.h
+--- linux-3.18.8.orig/arch/x86/include/asm/uv/uv_hub.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/include/asm/uv/uv_hub.h	2015-03-03 08:05:17.000000000 +0100
+@@ -492,7 +492,7 @@
+ 	unsigned short	nr_online_cpus;
+ 	unsigned short	pnode;
+ 	short		memory_nid;
+-	spinlock_t	nmi_lock;	/* obsolete, see uv_hub_nmi */
++	raw_spinlock_t	nmi_lock;	/* obsolete, see uv_hub_nmi */
+ 	unsigned long	nmi_count;	/* obsolete, see uv_hub_nmi */
+ };
+ extern struct uv_blade_info *uv_blade_info;
+diff -Nur linux-3.18.8.orig/arch/x86/Kconfig linux-3.18.8/arch/x86/Kconfig
+--- linux-3.18.8.orig/arch/x86/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/Kconfig	2015-03-03 08:05:17.000000000 +0100
+@@ -21,6 +21,7 @@
+ ### Arch settings
+ config X86
+ 	def_bool y
++	select HAVE_PREEMPT_LAZY if X86_32
+ 	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
+ 	select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
+ 	select ARCH_HAS_FAST_MULTIPLIER
+@@ -197,8 +198,11 @@
+ 	def_bool y
+ 	depends on ISA_DMA_API
+ 
++config RWSEM_GENERIC_SPINLOCK
++	def_bool PREEMPT_RT_FULL
++
+ config RWSEM_XCHGADD_ALGORITHM
+-	def_bool y
++	def_bool !RWSEM_GENERIC_SPINLOCK && !PREEMPT_RT_FULL
+ 
+ config GENERIC_CALIBRATE_DELAY
+ 	def_bool y
+@@ -811,7 +815,7 @@
+ config MAXSMP
+ 	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
+ 	depends on X86_64 && SMP && DEBUG_KERNEL
+-	select CPUMASK_OFFSTACK
++	select CPUMASK_OFFSTACK if !PREEMPT_RT_FULL
+ 	---help---
+ 	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
+ 	  If unsure, say N.
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/apic/io_apic.c linux-3.18.8/arch/x86/kernel/apic/io_apic.c
+--- linux-3.18.8.orig/arch/x86/kernel/apic/io_apic.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/apic/io_apic.c	2015-03-03 08:05:17.000000000 +0100
+@@ -2494,7 +2494,8 @@
+ static inline bool ioapic_irqd_mask(struct irq_data *data, struct irq_cfg *cfg)
+ {
+ 	/* If we are moving the irq we need to mask it */
+-	if (unlikely(irqd_is_setaffinity_pending(data))) {
++	if (unlikely(irqd_is_setaffinity_pending(data) &&
++		     !irqd_irq_inprogress(data))) {
+ 		mask_ioapic(cfg);
+ 		return true;
+ 	}
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/apic/x2apic_uv_x.c linux-3.18.8/arch/x86/kernel/apic/x2apic_uv_x.c
+--- linux-3.18.8.orig/arch/x86/kernel/apic/x2apic_uv_x.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/apic/x2apic_uv_x.c	2015-03-03 08:05:17.000000000 +0100
+@@ -918,7 +918,7 @@
+ 			uv_blade_info[blade].pnode = pnode;
+ 			uv_blade_info[blade].nr_possible_cpus = 0;
+ 			uv_blade_info[blade].nr_online_cpus = 0;
+-			spin_lock_init(&uv_blade_info[blade].nmi_lock);
++			raw_spin_lock_init(&uv_blade_info[blade].nmi_lock);
+ 			min_pnode = min(pnode, min_pnode);
+ 			max_pnode = max(pnode, max_pnode);
+ 			blade++;
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/asm-offsets.c linux-3.18.8/arch/x86/kernel/asm-offsets.c
+--- linux-3.18.8.orig/arch/x86/kernel/asm-offsets.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/asm-offsets.c	2015-03-03 08:05:17.000000000 +0100
+@@ -32,6 +32,7 @@
+ 	OFFSET(TI_flags, thread_info, flags);
+ 	OFFSET(TI_status, thread_info, status);
+ 	OFFSET(TI_addr_limit, thread_info, addr_limit);
++	OFFSET(TI_preempt_lazy_count, thread_info, preempt_lazy_count);
+ 
+ 	BLANK();
+ 	OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx);
+@@ -71,4 +72,5 @@
+ 
+ 	BLANK();
+ 	DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
++	DEFINE(_PREEMPT_ENABLED, PREEMPT_ENABLED);
+ }
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/cpu/mcheck/mce.c linux-3.18.8/arch/x86/kernel/cpu/mcheck/mce.c
+--- linux-3.18.8.orig/arch/x86/kernel/cpu/mcheck/mce.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/cpu/mcheck/mce.c	2015-03-03 08:05:17.000000000 +0100
+@@ -18,6 +18,7 @@
+ #include <linux/rcupdate.h>
+ #include <linux/kobject.h>
+ #include <linux/uaccess.h>
++#include <linux/kthread.h>
+ #include <linux/kdebug.h>
+ #include <linux/kernel.h>
+ #include <linux/percpu.h>
+@@ -41,6 +42,7 @@
+ #include <linux/debugfs.h>
+ #include <linux/irq_work.h>
+ #include <linux/export.h>
++#include <linux/jiffies.h>
+ 
+ #include <asm/processor.h>
+ #include <asm/mce.h>
+@@ -1266,7 +1268,7 @@
+ static unsigned long check_interval = 5 * 60; /* 5 minutes */
+ 
+ static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */
+-static DEFINE_PER_CPU(struct timer_list, mce_timer);
++static DEFINE_PER_CPU(struct hrtimer, mce_timer);
+ 
+ static unsigned long mce_adjust_timer_default(unsigned long interval)
+ {
+@@ -1283,14 +1285,11 @@
+ 	return test_and_clear_bit(0, v);
+ }
+ 
+-static void mce_timer_fn(unsigned long data)
++static enum hrtimer_restart mce_timer_fn(struct hrtimer *timer)
+ {
+-	struct timer_list *t = this_cpu_ptr(&mce_timer);
+ 	unsigned long iv;
+ 	int notify;
+ 
+-	WARN_ON(smp_processor_id() != data);
+-
+ 	if (mce_available(this_cpu_ptr(&cpu_info))) {
+ 		machine_check_poll(MCP_TIMESTAMP,
+ 				this_cpu_ptr(&mce_poll_banks));
+@@ -1313,9 +1312,11 @@
+ 	__this_cpu_write(mce_next_interval, iv);
+ 	/* Might have become 0 after CMCI storm subsided */
+ 	if (iv) {
+-		t->expires = jiffies + iv;
+-		add_timer_on(t, smp_processor_id());
++		hrtimer_forward_now(timer, ns_to_ktime(
++					jiffies_to_usecs(iv) * 1000ULL));
++		return HRTIMER_RESTART;
+ 	}
++	return HRTIMER_NORESTART;
+ }
+ 
+ /*
+@@ -1323,28 +1324,37 @@
+  */
+ void mce_timer_kick(unsigned long interval)
+ {
+-	struct timer_list *t = this_cpu_ptr(&mce_timer);
+-	unsigned long when = jiffies + interval;
++	struct hrtimer *t = this_cpu_ptr(&mce_timer);
+ 	unsigned long iv = __this_cpu_read(mce_next_interval);
+ 
+-	if (timer_pending(t)) {
+-		if (time_before(when, t->expires))
+-			mod_timer_pinned(t, when);
++	if (hrtimer_active(t)) {
++		s64 exp;
++		s64 intv_us;
++
++		intv_us = jiffies_to_usecs(interval);
++		exp = ktime_to_us(hrtimer_expires_remaining(t));
++		if (intv_us < exp) {
++			hrtimer_cancel(t);
++			hrtimer_start_range_ns(t,
++					ns_to_ktime(intv_us * 1000),
++					0, HRTIMER_MODE_REL_PINNED);
++		}
+ 	} else {
+-		t->expires = round_jiffies(when);
+-		add_timer_on(t, smp_processor_id());
++		hrtimer_start_range_ns(t,
++			ns_to_ktime(jiffies_to_usecs(interval) * 1000ULL),
++				0, HRTIMER_MODE_REL_PINNED);
+ 	}
+ 	if (interval < iv)
+ 		__this_cpu_write(mce_next_interval, interval);
+ }
+ 
+-/* Must not be called in IRQ context where del_timer_sync() can deadlock */
++/* Must not be called in IRQ context where hrtimer_cancel() can deadlock */
+ static void mce_timer_delete_all(void)
+ {
+ 	int cpu;
+ 
+ 	for_each_online_cpu(cpu)
+-		del_timer_sync(&per_cpu(mce_timer, cpu));
++		hrtimer_cancel(&per_cpu(mce_timer, cpu));
+ }
+ 
+ static void mce_do_trigger(struct work_struct *work)
+@@ -1354,6 +1364,68 @@
+ 
+ static DECLARE_WORK(mce_trigger_work, mce_do_trigger);
+ 
++static void __mce_notify_work(void)
++{
++	/* Not more than two messages every minute */
++	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
++
++	/* wake processes polling /dev/mcelog */
++	wake_up_interruptible(&mce_chrdev_wait);
++
++	/*
++	 * There is no risk of missing notifications because
++	 * work_pending is always cleared before the function is
++	 * executed.
++	 */
++	if (mce_helper[0] && !work_pending(&mce_trigger_work))
++		schedule_work(&mce_trigger_work);
++
++	if (__ratelimit(&ratelimit))
++		pr_info(HW_ERR "Machine check events logged\n");
++}
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++struct task_struct *mce_notify_helper;
++
++static int mce_notify_helper_thread(void *unused)
++{
++	while (1) {
++		set_current_state(TASK_INTERRUPTIBLE);
++		schedule();
++		if (kthread_should_stop())
++			break;
++		__mce_notify_work();
++	}
++	return 0;
++}
++
++static int mce_notify_work_init(void)
++{
++	mce_notify_helper = kthread_run(mce_notify_helper_thread, NULL,
++					   "mce-notify");
++	if (!mce_notify_helper)
++		return -ENOMEM;
++
++	return 0;
++}
++
++static void mce_notify_work(void)
++{
++	if (WARN_ON_ONCE(!mce_notify_helper)) {
++		pr_info(HW_ERR "Machine check event before MCE init; ignored\n");
++		return;
++	}
++
++	wake_up_process(mce_notify_helper);
++}
++#else
++static void mce_notify_work(void)
++{
++	__mce_notify_work();
++}
++static inline int mce_notify_work_init(void) { return 0; }
++#endif
++
+ /*
+  * Notify the user(s) about new machine check events.
+  * Can be called from interrupt context, but not from machine check/NMI
+@@ -1361,19 +1433,8 @@
+  */
+ int mce_notify_irq(void)
+ {
+-	/* Not more than two messages every minute */
+-	static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
+-
+ 	if (test_and_clear_bit(0, &mce_need_notify)) {
+-		/* wake processes polling /dev/mcelog */
+-		wake_up_interruptible(&mce_chrdev_wait);
+-
+-		if (mce_helper[0])
+-			schedule_work(&mce_trigger_work);
+-
+-		if (__ratelimit(&ratelimit))
+-			pr_info(HW_ERR "Machine check events logged\n");
+-
++		mce_notify_work();
+ 		return 1;
+ 	}
+ 	return 0;
+@@ -1644,7 +1705,7 @@
+ 	}
+ }
+ 
+-static void mce_start_timer(unsigned int cpu, struct timer_list *t)
++static void mce_start_timer(unsigned int cpu, struct hrtimer *t)
+ {
+ 	unsigned long iv = check_interval * HZ;
+ 
+@@ -1653,16 +1714,17 @@
+ 
+ 	per_cpu(mce_next_interval, cpu) = iv;
+ 
+-	t->expires = round_jiffies(jiffies + iv);
+-	add_timer_on(t, cpu);
++	hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(iv) * 1000ULL),
++			0, HRTIMER_MODE_REL_PINNED);
+ }
+ 
+ static void __mcheck_cpu_init_timer(void)
+ {
+-	struct timer_list *t = this_cpu_ptr(&mce_timer);
++	struct hrtimer *t = this_cpu_ptr(&mce_timer);
+ 	unsigned int cpu = smp_processor_id();
+ 
+-	setup_timer(t, mce_timer_fn, cpu);
++	hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
++	t->function = mce_timer_fn;
+ 	mce_start_timer(cpu, t);
+ }
+ 
+@@ -2339,6 +2401,8 @@
+ 	if (!mce_available(raw_cpu_ptr(&cpu_info)))
+ 		return;
+ 
++	hrtimer_cancel(this_cpu_ptr(&mce_timer));
++
+ 	if (!(action & CPU_TASKS_FROZEN))
+ 		cmci_clear();
+ 	for (i = 0; i < mca_cfg.banks; i++) {
+@@ -2365,6 +2429,7 @@
+ 		if (b->init)
+ 			wrmsrl(MSR_IA32_MCx_CTL(i), b->ctl);
+ 	}
++	__mcheck_cpu_init_timer();
+ }
+ 
+ /* Get notified when a cpu comes on/off. Be hotplug friendly. */
+@@ -2372,7 +2437,6 @@
+ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+ {
+ 	unsigned int cpu = (unsigned long)hcpu;
+-	struct timer_list *t = &per_cpu(mce_timer, cpu);
+ 
+ 	switch (action & ~CPU_TASKS_FROZEN) {
+ 	case CPU_ONLINE:
+@@ -2392,11 +2456,9 @@
+ 		break;
+ 	case CPU_DOWN_PREPARE:
+ 		smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
+-		del_timer_sync(t);
+ 		break;
+ 	case CPU_DOWN_FAILED:
+ 		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
+-		mce_start_timer(cpu, t);
+ 		break;
+ 	}
+ 
+@@ -2471,8 +2533,15 @@
+ 	if (err)
+ 		goto err_register;
+ 
++	err = mce_notify_work_init();
++	if (err)
++		goto err_notify;
++
+ 	return 0;
+ 
++err_notify:
++	misc_deregister(&mce_chrdev_device);
++
+ err_register:
+ 	unregister_syscore_ops(&mce_syscore_ops);
+ 
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/entry_32.S linux-3.18.8/arch/x86/kernel/entry_32.S
+--- linux-3.18.8.orig/arch/x86/kernel/entry_32.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/entry_32.S	2015-03-03 08:05:17.000000000 +0100
+@@ -359,8 +359,24 @@
+ ENTRY(resume_kernel)
+ 	DISABLE_INTERRUPTS(CLBR_ANY)
+ need_resched:
++	# preempt count == 0 + NEED_RS set?
+ 	cmpl $0,PER_CPU_VAR(__preempt_count)
++#ifndef CONFIG_PREEMPT_LAZY
+ 	jnz restore_all
++#else
++	jz test_int_off
++
++	# atleast preempt count == 0 ?
++	cmpl $_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
++	jne restore_all
++
++	cmpl $0,TI_preempt_lazy_count(%ebp)	# non-zero preempt_lazy_count ?
++	jnz restore_all
++
++	testl $_TIF_NEED_RESCHED_LAZY, TI_flags(%ebp)
++	jz restore_all
++test_int_off:
++#endif
+ 	testl $X86_EFLAGS_IF,PT_EFLAGS(%esp)	# interrupts off (exception path) ?
+ 	jz restore_all
+ 	call preempt_schedule_irq
+@@ -591,7 +607,7 @@
+ 	ALIGN
+ 	RING0_PTREGS_FRAME		# can't unwind into user space anyway
+ work_pending:
+-	testb $_TIF_NEED_RESCHED, %cl
++	testl $_TIF_NEED_RESCHED_MASK, %ecx
+ 	jz work_notifysig
+ work_resched:
+ 	call schedule
+@@ -604,7 +620,7 @@
+ 	andl $_TIF_WORK_MASK, %ecx	# is there any work to be done other
+ 					# than syscall tracing?
+ 	jz restore_all
+-	testb $_TIF_NEED_RESCHED, %cl
++	testl $_TIF_NEED_RESCHED_MASK, %ecx
+ 	jnz work_resched
+ 
+ work_notifysig:				# deal with pending signals and
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/entry_64.S linux-3.18.8/arch/x86/kernel/entry_64.S
+--- linux-3.18.8.orig/arch/x86/kernel/entry_64.S	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/entry_64.S	2015-03-03 08:05:17.000000000 +0100
+@@ -451,8 +451,8 @@
+ 	/* Handle reschedules */
+ 	/* edx:	work, edi: workmask */
+ sysret_careful:
+-	bt $TIF_NEED_RESCHED,%edx
+-	jnc sysret_signal
++	testl $_TIF_NEED_RESCHED_MASK,%edx
++	jz sysret_signal
+ 	TRACE_IRQS_ON
+ 	ENABLE_INTERRUPTS(CLBR_NONE)
+ 	pushq_cfi %rdi
+@@ -551,8 +551,8 @@
+ 	/* First do a reschedule test. */
+ 	/* edx:	work, edi: workmask */
+ int_careful:
+-	bt $TIF_NEED_RESCHED,%edx
+-	jnc  int_very_careful
++	testl $_TIF_NEED_RESCHED_MASK,%edx
++	jz  int_very_careful
+ 	TRACE_IRQS_ON
+ 	ENABLE_INTERRUPTS(CLBR_NONE)
+ 	pushq_cfi %rdi
+@@ -867,8 +867,8 @@
+ 	/* edi: workmask, edx: work */
+ retint_careful:
+ 	CFI_RESTORE_STATE
+-	bt    $TIF_NEED_RESCHED,%edx
+-	jnc   retint_signal
++	testl $_TIF_NEED_RESCHED_MASK,%edx
++	jz   retint_signal
+ 	TRACE_IRQS_ON
+ 	ENABLE_INTERRUPTS(CLBR_NONE)
+ 	pushq_cfi %rdi
+@@ -900,7 +900,22 @@
+ 	/* rcx:	 threadinfo. interrupts off. */
+ ENTRY(retint_kernel)
+ 	cmpl $0,PER_CPU_VAR(__preempt_count)
++#ifndef CONFIG_PREEMPT_LAZY
+ 	jnz  retint_restore_args
++#else
++	jz  check_int_off
++
++	# atleast preempt count == 0 ?
++	cmpl $_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
++	jnz retint_restore_args
++
++	cmpl $0, TI_preempt_lazy_count(%rcx)
++	jnz retint_restore_args
++
++	bt $TIF_NEED_RESCHED_LAZY,TI_flags(%rcx)
++	jnc  retint_restore_args
++check_int_off:
++#endif
+ 	bt   $9,EFLAGS-ARGOFFSET(%rsp)	/* interrupts off? */
+ 	jnc  retint_restore_args
+ 	call preempt_schedule_irq
+@@ -1116,6 +1131,7 @@
+ 	jmp  2b
+ 	.previous
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /* Call softirq on interrupt stack. Interrupts are off. */
+ ENTRY(do_softirq_own_stack)
+ 	CFI_STARTPROC
+@@ -1135,6 +1151,7 @@
+ 	ret
+ 	CFI_ENDPROC
+ END(do_softirq_own_stack)
++#endif
+ 
+ #ifdef CONFIG_XEN
+ idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0
+@@ -1299,7 +1316,7 @@
+ 	movq %rsp,%rdi			/* &pt_regs */
+ 	call sync_regs
+ 	movq %rax,%rsp			/* switch stack for scheduling */
+-	testl $_TIF_NEED_RESCHED,%ebx
++	testl $_TIF_NEED_RESCHED_MASK,%ebx
+ 	jnz paranoid_schedule
+ 	movl %ebx,%edx			/* arg3: thread flags */
+ 	TRACE_IRQS_ON
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/irq_32.c linux-3.18.8/arch/x86/kernel/irq_32.c
+--- linux-3.18.8.orig/arch/x86/kernel/irq_32.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/irq_32.c	2015-03-03 08:05:17.000000000 +0100
+@@ -142,6 +142,7 @@
+ 	       cpu, per_cpu(hardirq_stack, cpu),  per_cpu(softirq_stack, cpu));
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void do_softirq_own_stack(void)
+ {
+ 	struct thread_info *curstk;
+@@ -160,6 +161,7 @@
+ 
+ 	call_on_stack(__do_softirq, isp);
+ }
++#endif
+ 
+ bool handle_irq(unsigned irq, struct pt_regs *regs)
+ {
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/irq_work.c linux-3.18.8/arch/x86/kernel/irq_work.c
+--- linux-3.18.8.orig/arch/x86/kernel/irq_work.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/irq_work.c	2015-03-03 08:05:17.000000000 +0100
+@@ -38,6 +38,7 @@
+ 	exiting_irq();
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void arch_irq_work_raise(void)
+ {
+ #ifdef CONFIG_X86_LOCAL_APIC
+@@ -48,3 +49,4 @@
+ 	apic_wait_icr_idle();
+ #endif
+ }
++#endif
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/process_32.c linux-3.18.8/arch/x86/kernel/process_32.c
+--- linux-3.18.8.orig/arch/x86/kernel/process_32.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/process_32.c	2015-03-03 08:05:17.000000000 +0100
+@@ -35,6 +35,7 @@
+ #include <linux/uaccess.h>
+ #include <linux/io.h>
+ #include <linux/kdebug.h>
++#include <linux/highmem.h>
+ 
+ #include <asm/pgtable.h>
+ #include <asm/ldt.h>
+@@ -214,6 +215,35 @@
+ }
+ EXPORT_SYMBOL_GPL(start_thread);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++static void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
++{
++	int i;
++
++	/*
++	 * Clear @prev's kmap_atomic mappings
++	 */
++	for (i = 0; i < prev_p->kmap_idx; i++) {
++		int idx = i + KM_TYPE_NR * smp_processor_id();
++		pte_t *ptep = kmap_pte - idx;
++
++		kpte_clear_flush(ptep, __fix_to_virt(FIX_KMAP_BEGIN + idx));
++	}
++	/*
++	 * Restore @next_p's kmap_atomic mappings
++	 */
++	for (i = 0; i < next_p->kmap_idx; i++) {
++		int idx = i + KM_TYPE_NR * smp_processor_id();
++
++		if (!pte_none(next_p->kmap_pte[i]))
++			set_pte(kmap_pte - idx, next_p->kmap_pte[i]);
++	}
++}
++#else
++static inline void
++switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
++#endif
++
+ 
+ /*
+  *	switch_to(x,y) should switch tasks from x to y.
+@@ -301,6 +331,8 @@
+ 		     task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT))
+ 		__switch_to_xtra(prev_p, next_p, tss);
+ 
++	switch_kmaps(prev_p, next_p);
++
+ 	/*
+ 	 * Leave lazy mode, flushing any hypercalls made here.
+ 	 * This must be done before restoring TLS segments so
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/signal.c linux-3.18.8/arch/x86/kernel/signal.c
+--- linux-3.18.8.orig/arch/x86/kernel/signal.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/signal.c	2015-03-03 08:05:17.000000000 +0100
+@@ -746,6 +746,14 @@
+ 		mce_notify_process();
+ #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
+ 
++#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
++	if (unlikely(current->forced_info.si_signo)) {
++		struct task_struct *t = current;
++		force_sig_info(t->forced_info.si_signo,	&t->forced_info, t);
++		t->forced_info.si_signo = 0;
++	}
++#endif
++
+ 	if (thread_info_flags & _TIF_UPROBE)
+ 		uprobe_notify_resume(regs);
+ 
+diff -Nur linux-3.18.8.orig/arch/x86/kernel/traps.c linux-3.18.8/arch/x86/kernel/traps.c
+--- linux-3.18.8.orig/arch/x86/kernel/traps.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kernel/traps.c	2015-03-03 08:05:17.000000000 +0100
+@@ -87,9 +87,21 @@
+ 		local_irq_enable();
+ }
+ 
+-static inline void preempt_conditional_sti(struct pt_regs *regs)
++static inline void conditional_sti_ist(struct pt_regs *regs)
+ {
++#ifdef CONFIG_X86_64
++	/*
++	 * X86_64 uses a per CPU stack on the IST for certain traps
++	 * like int3. The task can not be preempted when using one
++	 * of these stacks, thus preemption must be disabled, otherwise
++	 * the stack can be corrupted if the task is scheduled out,
++	 * and another task comes in and uses this stack.
++	 *
++	 * On x86_32 the task keeps its own stack and it is OK if the
++	 * task schedules out.
++	 */
+ 	preempt_count_inc();
++#endif
+ 	if (regs->flags & X86_EFLAGS_IF)
+ 		local_irq_enable();
+ }
+@@ -100,11 +112,13 @@
+ 		local_irq_disable();
+ }
+ 
+-static inline void preempt_conditional_cli(struct pt_regs *regs)
++static inline void conditional_cli_ist(struct pt_regs *regs)
+ {
+ 	if (regs->flags & X86_EFLAGS_IF)
+ 		local_irq_disable();
++#ifdef CONFIG_X86_64
+ 	preempt_count_dec();
++#endif
+ }
+ 
+ static nokprobe_inline int
+@@ -372,9 +386,9 @@
+ 	 * as we may switch to the interrupt stack.
+ 	 */
+ 	debug_stack_usage_inc();
+-	preempt_conditional_sti(regs);
++	conditional_sti_ist(regs);
+ 	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
+-	preempt_conditional_cli(regs);
++	conditional_cli_ist(regs);
+ 	debug_stack_usage_dec();
+ exit:
+ 	exception_exit(prev_state);
+@@ -517,12 +531,12 @@
+ 	debug_stack_usage_inc();
+ 
+ 	/* It's safe to allow irq's after DR6 has been saved */
+-	preempt_conditional_sti(regs);
++	conditional_sti_ist(regs);
+ 
+ 	if (regs->flags & X86_VM_MASK) {
+ 		handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
+ 					X86_TRAP_DB);
+-		preempt_conditional_cli(regs);
++		conditional_cli_ist(regs);
+ 		debug_stack_usage_dec();
+ 		goto exit;
+ 	}
+@@ -542,7 +556,7 @@
+ 	si_code = get_si_code(tsk->thread.debugreg6);
+ 	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
+ 		send_sigtrap(tsk, regs, error_code, si_code);
+-	preempt_conditional_cli(regs);
++	conditional_cli_ist(regs);
+ 	debug_stack_usage_dec();
+ 
+ exit:
+diff -Nur linux-3.18.8.orig/arch/x86/kvm/x86.c linux-3.18.8/arch/x86/kvm/x86.c
+--- linux-3.18.8.orig/arch/x86/kvm/x86.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/kvm/x86.c	2015-03-03 08:05:17.000000000 +0100
+@@ -5772,6 +5772,13 @@
+ 		goto out;
+ 	}
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
++		printk(KERN_ERR "RT requires X86_FEATURE_CONSTANT_TSC\n");
++		return -EOPNOTSUPP;
++	}
++#endif
++
+ 	r = kvm_mmu_module_init();
+ 	if (r)
+ 		goto out_free_percpu;
+diff -Nur linux-3.18.8.orig/arch/x86/mm/fault.c linux-3.18.8/arch/x86/mm/fault.c
+--- linux-3.18.8.orig/arch/x86/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -1128,7 +1128,7 @@
+ 	 * If we're in an interrupt, have no user context or are running
+ 	 * in an atomic region then we must not take the fault:
+ 	 */
+-	if (unlikely(in_atomic() || !mm)) {
++	if (unlikely(!mm || pagefault_disabled())) {
+ 		bad_area_nosemaphore(regs, error_code, address);
+ 		return;
+ 	}
+diff -Nur linux-3.18.8.orig/arch/x86/mm/highmem_32.c linux-3.18.8/arch/x86/mm/highmem_32.c
+--- linux-3.18.8.orig/arch/x86/mm/highmem_32.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/mm/highmem_32.c	2015-03-03 08:05:17.000000000 +0100
+@@ -32,6 +32,7 @@
+  */
+ void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+ {
++	pte_t pte = mk_pte(page, prot);
+ 	unsigned long vaddr;
+ 	int idx, type;
+ 
+@@ -45,7 +46,10 @@
+ 	idx = type + KM_TYPE_NR*smp_processor_id();
+ 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+ 	BUG_ON(!pte_none(*(kmap_pte-idx)));
+-	set_pte(kmap_pte-idx, mk_pte(page, prot));
++#ifdef CONFIG_PREEMPT_RT_FULL
++	current->kmap_pte[type] = pte;
++#endif
++	set_pte(kmap_pte-idx, pte);
+ 	arch_flush_lazy_mmu_mode();
+ 
+ 	return (void *)vaddr;
+@@ -88,6 +92,9 @@
+ 		 * is a bad idea also, in case the page changes cacheability
+ 		 * attributes or becomes a protected page in a hypervisor.
+ 		 */
++#ifdef CONFIG_PREEMPT_RT_FULL
++		current->kmap_pte[type] = __pte(0);
++#endif
+ 		kpte_clear_flush(kmap_pte-idx, vaddr);
+ 		kmap_atomic_idx_pop();
+ 		arch_flush_lazy_mmu_mode();
+diff -Nur linux-3.18.8.orig/arch/x86/mm/iomap_32.c linux-3.18.8/arch/x86/mm/iomap_32.c
+--- linux-3.18.8.orig/arch/x86/mm/iomap_32.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/mm/iomap_32.c	2015-03-03 08:05:17.000000000 +0100
+@@ -56,6 +56,7 @@
+ 
+ void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
+ {
++	pte_t pte = pfn_pte(pfn, prot);
+ 	unsigned long vaddr;
+ 	int idx, type;
+ 
+@@ -64,7 +65,12 @@
+ 	type = kmap_atomic_idx_push();
+ 	idx = type + KM_TYPE_NR * smp_processor_id();
+ 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
++	WARN_ON(!pte_none(*(kmap_pte - idx)));
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++	current->kmap_pte[type] = pte;
++#endif
++	set_pte(kmap_pte - idx, pte);
+ 	arch_flush_lazy_mmu_mode();
+ 
+ 	return (void *)vaddr;
+@@ -110,6 +116,9 @@
+ 		 * is a bad idea also, in case the page changes cacheability
+ 		 * attributes or becomes a protected page in a hypervisor.
+ 		 */
++#ifdef CONFIG_PREEMPT_RT_FULL
++		current->kmap_pte[type] = __pte(0);
++#endif
+ 		kpte_clear_flush(kmap_pte-idx, vaddr);
+ 		kmap_atomic_idx_pop();
+ 	}
+diff -Nur linux-3.18.8.orig/arch/x86/platform/uv/tlb_uv.c linux-3.18.8/arch/x86/platform/uv/tlb_uv.c
+--- linux-3.18.8.orig/arch/x86/platform/uv/tlb_uv.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/platform/uv/tlb_uv.c	2015-03-03 08:05:17.000000000 +0100
+@@ -714,9 +714,9 @@
+ 
+ 		quiesce_local_uvhub(hmaster);
+ 
+-		spin_lock(&hmaster->queue_lock);
++		raw_spin_lock(&hmaster->queue_lock);
+ 		reset_with_ipi(&bau_desc->distribution, bcp);
+-		spin_unlock(&hmaster->queue_lock);
++		raw_spin_unlock(&hmaster->queue_lock);
+ 
+ 		end_uvhub_quiesce(hmaster);
+ 
+@@ -736,9 +736,9 @@
+ 
+ 		quiesce_local_uvhub(hmaster);
+ 
+-		spin_lock(&hmaster->queue_lock);
++		raw_spin_lock(&hmaster->queue_lock);
+ 		reset_with_ipi(&bau_desc->distribution, bcp);
+-		spin_unlock(&hmaster->queue_lock);
++		raw_spin_unlock(&hmaster->queue_lock);
+ 
+ 		end_uvhub_quiesce(hmaster);
+ 
+@@ -759,7 +759,7 @@
+ 	cycles_t tm1;
+ 
+ 	hmaster = bcp->uvhub_master;
+-	spin_lock(&hmaster->disable_lock);
++	raw_spin_lock(&hmaster->disable_lock);
+ 	if (!bcp->baudisabled) {
+ 		stat->s_bau_disabled++;
+ 		tm1 = get_cycles();
+@@ -772,7 +772,7 @@
+ 			}
+ 		}
+ 	}
+-	spin_unlock(&hmaster->disable_lock);
++	raw_spin_unlock(&hmaster->disable_lock);
+ }
+ 
+ static void count_max_concurr(int stat, struct bau_control *bcp,
+@@ -835,7 +835,7 @@
+  */
+ static void uv1_throttle(struct bau_control *hmaster, struct ptc_stats *stat)
+ {
+-	spinlock_t *lock = &hmaster->uvhub_lock;
++	raw_spinlock_t *lock = &hmaster->uvhub_lock;
+ 	atomic_t *v;
+ 
+ 	v = &hmaster->active_descriptor_count;
+@@ -968,7 +968,7 @@
+ 	struct bau_control *hmaster;
+ 
+ 	hmaster = bcp->uvhub_master;
+-	spin_lock(&hmaster->disable_lock);
++	raw_spin_lock(&hmaster->disable_lock);
+ 	if (bcp->baudisabled && (get_cycles() >= bcp->set_bau_on_time)) {
+ 		stat->s_bau_reenabled++;
+ 		for_each_present_cpu(tcpu) {
+@@ -980,10 +980,10 @@
+ 				tbcp->period_giveups = 0;
+ 			}
+ 		}
+-		spin_unlock(&hmaster->disable_lock);
++		raw_spin_unlock(&hmaster->disable_lock);
+ 		return 0;
+ 	}
+-	spin_unlock(&hmaster->disable_lock);
++	raw_spin_unlock(&hmaster->disable_lock);
+ 	return -1;
+ }
+ 
+@@ -1899,9 +1899,9 @@
+ 		bcp->cong_reps			= congested_reps;
+ 		bcp->disabled_period =		sec_2_cycles(disabled_period);
+ 		bcp->giveup_limit =		giveup_limit;
+-		spin_lock_init(&bcp->queue_lock);
+-		spin_lock_init(&bcp->uvhub_lock);
+-		spin_lock_init(&bcp->disable_lock);
++		raw_spin_lock_init(&bcp->queue_lock);
++		raw_spin_lock_init(&bcp->uvhub_lock);
++		raw_spin_lock_init(&bcp->disable_lock);
+ 	}
+ }
+ 
+diff -Nur linux-3.18.8.orig/arch/x86/platform/uv/uv_time.c linux-3.18.8/arch/x86/platform/uv/uv_time.c
+--- linux-3.18.8.orig/arch/x86/platform/uv/uv_time.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/x86/platform/uv/uv_time.c	2015-03-03 08:05:17.000000000 +0100
+@@ -58,7 +58,7 @@
+ 
+ /* There is one of these allocated per node */
+ struct uv_rtc_timer_head {
+-	spinlock_t	lock;
++	raw_spinlock_t	lock;
+ 	/* next cpu waiting for timer, local node relative: */
+ 	int		next_cpu;
+ 	/* number of cpus on this node: */
+@@ -178,7 +178,7 @@
+ 				uv_rtc_deallocate_timers();
+ 				return -ENOMEM;
+ 			}
+-			spin_lock_init(&head->lock);
++			raw_spin_lock_init(&head->lock);
+ 			head->ncpus = uv_blade_nr_possible_cpus(bid);
+ 			head->next_cpu = -1;
+ 			blade_info[bid] = head;
+@@ -232,7 +232,7 @@
+ 	unsigned long flags;
+ 	int next_cpu;
+ 
+-	spin_lock_irqsave(&head->lock, flags);
++	raw_spin_lock_irqsave(&head->lock, flags);
+ 
+ 	next_cpu = head->next_cpu;
+ 	*t = expires;
+@@ -244,12 +244,12 @@
+ 		if (uv_setup_intr(cpu, expires)) {
+ 			*t = ULLONG_MAX;
+ 			uv_rtc_find_next_timer(head, pnode);
+-			spin_unlock_irqrestore(&head->lock, flags);
++			raw_spin_unlock_irqrestore(&head->lock, flags);
+ 			return -ETIME;
+ 		}
+ 	}
+ 
+-	spin_unlock_irqrestore(&head->lock, flags);
++	raw_spin_unlock_irqrestore(&head->lock, flags);
+ 	return 0;
+ }
+ 
+@@ -268,7 +268,7 @@
+ 	unsigned long flags;
+ 	int rc = 0;
+ 
+-	spin_lock_irqsave(&head->lock, flags);
++	raw_spin_lock_irqsave(&head->lock, flags);
+ 
+ 	if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
+ 		rc = 1;
+@@ -280,7 +280,7 @@
+ 			uv_rtc_find_next_timer(head, pnode);
+ 	}
+ 
+-	spin_unlock_irqrestore(&head->lock, flags);
++	raw_spin_unlock_irqrestore(&head->lock, flags);
+ 
+ 	return rc;
+ }
+@@ -300,13 +300,18 @@
+ static cycle_t uv_read_rtc(struct clocksource *cs)
+ {
+ 	unsigned long offset;
++	cycle_t cycles;
+ 
++	preempt_disable();
+ 	if (uv_get_min_hub_revision_id() == 1)
+ 		offset = 0;
+ 	else
+ 		offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
+ 
+-	return (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
++	cycles = (cycle_t)uv_read_local_mmr(UVH_RTC | offset);
++	preempt_enable();
++
++	return cycles;
+ }
+ 
+ /*
+diff -Nur linux-3.18.8.orig/arch/xtensa/mm/fault.c linux-3.18.8/arch/xtensa/mm/fault.c
+--- linux-3.18.8.orig/arch/xtensa/mm/fault.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/arch/xtensa/mm/fault.c	2015-03-03 08:05:17.000000000 +0100
+@@ -57,7 +57,7 @@
+ 	/* If we're in an interrupt or have no user
+ 	 * context, we must not take the fault..
+ 	 */
+-	if (in_atomic() || !mm) {
++	if (!mm || pagefault_disabled()) {
+ 		bad_page_fault(regs, address, SIGSEGV);
+ 		return;
+ 	}
+diff -Nur linux-3.18.8.orig/block/blk-core.c linux-3.18.8/block/blk-core.c
+--- linux-3.18.8.orig/block/blk-core.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-core.c	2015-03-03 08:05:17.000000000 +0100
+@@ -100,6 +100,9 @@
+ 
+ 	INIT_LIST_HEAD(&rq->queuelist);
+ 	INIT_LIST_HEAD(&rq->timeout_list);
++#if CONFIG_PREEMPT_RT_FULL
++	INIT_WORK(&rq->work, __blk_mq_complete_request_remote_work);
++#endif
+ 	rq->cpu = -1;
+ 	rq->q = q;
+ 	rq->__sector = (sector_t) -1;
+@@ -194,7 +197,7 @@
+  **/
+ void blk_start_queue(struct request_queue *q)
+ {
+-	WARN_ON(!irqs_disabled());
++	WARN_ON_NONRT(!irqs_disabled());
+ 
+ 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
+ 	__blk_run_queue(q);
+@@ -627,7 +630,7 @@
+ 	q->bypass_depth = 1;
+ 	__set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
+ 
+-	init_waitqueue_head(&q->mq_freeze_wq);
++	init_swait_head(&q->mq_freeze_wq);
+ 
+ 	if (blkcg_init_queue(q))
+ 		goto fail_bdi;
+@@ -3037,7 +3040,7 @@
+ 		blk_run_queue_async(q);
+ 	else
+ 		__blk_run_queue(q);
+-	spin_unlock(q->queue_lock);
++	spin_unlock_irq(q->queue_lock);
+ }
+ 
+ static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
+@@ -3085,7 +3088,6 @@
+ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
+ {
+ 	struct request_queue *q;
+-	unsigned long flags;
+ 	struct request *rq;
+ 	LIST_HEAD(list);
+ 	unsigned int depth;
+@@ -3105,11 +3107,6 @@
+ 	q = NULL;
+ 	depth = 0;
+ 
+-	/*
+-	 * Save and disable interrupts here, to avoid doing it for every
+-	 * queue lock we have to take.
+-	 */
+-	local_irq_save(flags);
+ 	while (!list_empty(&list)) {
+ 		rq = list_entry_rq(list.next);
+ 		list_del_init(&rq->queuelist);
+@@ -3122,7 +3119,7 @@
+ 				queue_unplugged(q, depth, from_schedule);
+ 			q = rq->q;
+ 			depth = 0;
+-			spin_lock(q->queue_lock);
++			spin_lock_irq(q->queue_lock);
+ 		}
+ 
+ 		/*
+@@ -3149,8 +3146,6 @@
+ 	 */
+ 	if (q)
+ 		queue_unplugged(q, depth, from_schedule);
+-
+-	local_irq_restore(flags);
+ }
+ 
+ void blk_finish_plug(struct blk_plug *plug)
+diff -Nur linux-3.18.8.orig/block/blk-ioc.c linux-3.18.8/block/blk-ioc.c
+--- linux-3.18.8.orig/block/blk-ioc.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-ioc.c	2015-03-03 08:05:17.000000000 +0100
+@@ -7,6 +7,7 @@
+ #include <linux/bio.h>
+ #include <linux/blkdev.h>
+ #include <linux/slab.h>
++#include <linux/delay.h>
+ 
+ #include "blk.h"
+ 
+@@ -109,7 +110,7 @@
+ 			spin_unlock(q->queue_lock);
+ 		} else {
+ 			spin_unlock_irqrestore(&ioc->lock, flags);
+-			cpu_relax();
++			cpu_chill();
+ 			spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ 		}
+ 	}
+@@ -187,7 +188,7 @@
+ 			spin_unlock(icq->q->queue_lock);
+ 		} else {
+ 			spin_unlock_irqrestore(&ioc->lock, flags);
+-			cpu_relax();
++			cpu_chill();
+ 			goto retry;
+ 		}
+ 	}
+diff -Nur linux-3.18.8.orig/block/blk-iopoll.c linux-3.18.8/block/blk-iopoll.c
+--- linux-3.18.8.orig/block/blk-iopoll.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-iopoll.c	2015-03-03 08:05:17.000000000 +0100
+@@ -35,6 +35,7 @@
+ 	list_add_tail(&iop->list, this_cpu_ptr(&blk_cpu_iopoll));
+ 	__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(blk_iopoll_sched);
+ 
+@@ -132,6 +133,7 @@
+ 		__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
+ 
+ 	local_irq_enable();
++	preempt_check_resched_rt();
+ }
+ 
+ /**
+@@ -201,6 +203,7 @@
+ 				 this_cpu_ptr(&blk_cpu_iopoll));
+ 		__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
+ 		local_irq_enable();
++		preempt_check_resched_rt();
+ 	}
+ 
+ 	return NOTIFY_OK;
+diff -Nur linux-3.18.8.orig/block/blk-mq.c linux-3.18.8/block/blk-mq.c
+--- linux-3.18.8.orig/block/blk-mq.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-mq.c	2015-03-03 08:05:17.000000000 +0100
+@@ -85,7 +85,7 @@
+ 		if (percpu_ref_tryget_live(&q->mq_usage_counter))
+ 			return 0;
+ 
+-		ret = wait_event_interruptible(q->mq_freeze_wq,
++		ret = swait_event_interruptible(q->mq_freeze_wq,
+ 				!q->mq_freeze_depth || blk_queue_dying(q));
+ 		if (blk_queue_dying(q))
+ 			return -ENODEV;
+@@ -104,7 +104,7 @@
+ 	struct request_queue *q =
+ 		container_of(ref, struct request_queue, mq_usage_counter);
+ 
+-	wake_up_all(&q->mq_freeze_wq);
++	swait_wake_all(&q->mq_freeze_wq);
+ }
+ 
+ static void blk_mq_freeze_queue_start(struct request_queue *q)
+@@ -123,7 +123,7 @@
+ 
+ static void blk_mq_freeze_queue_wait(struct request_queue *q)
+ {
+-	wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter));
++	swait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter));
+ }
+ 
+ /*
+@@ -146,7 +146,7 @@
+ 	spin_unlock_irq(q->queue_lock);
+ 	if (wake) {
+ 		percpu_ref_reinit(&q->mq_usage_counter);
+-		wake_up_all(&q->mq_freeze_wq);
++		swait_wake_all(&q->mq_freeze_wq);
+ 	}
+ }
+ 
+@@ -194,6 +194,9 @@
+ 	rq->resid_len = 0;
+ 	rq->sense = NULL;
+ 
++#if CONFIG_PREEMPT_RT_FULL
++	INIT_WORK(&rq->work, __blk_mq_complete_request_remote_work);
++#endif
+ 	INIT_LIST_HEAD(&rq->timeout_list);
+ 	rq->timeout = 0;
+ 
+@@ -313,6 +316,17 @@
+ }
+ EXPORT_SYMBOL(blk_mq_end_request);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++
++void __blk_mq_complete_request_remote_work(struct work_struct *work)
++{
++	struct request *rq = container_of(work, struct request, work);
++
++	rq->q->softirq_done_fn(rq);
++}
++
++#else
++
+ static void __blk_mq_complete_request_remote(void *data)
+ {
+ 	struct request *rq = data;
+@@ -320,6 +334,8 @@
+ 	rq->q->softirq_done_fn(rq);
+ }
+ 
++#endif
++
+ static void blk_mq_ipi_complete_request(struct request *rq)
+ {
+ 	struct blk_mq_ctx *ctx = rq->mq_ctx;
+@@ -331,19 +347,23 @@
+ 		return;
+ 	}
+ 
+-	cpu = get_cpu();
++	cpu = get_cpu_light();
+ 	if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags))
+ 		shared = cpus_share_cache(cpu, ctx->cpu);
+ 
+ 	if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) {
++#if CONFIG_PREEMPT_RT_FULL
++		schedule_work_on(ctx->cpu, &rq->work);
++#else
+ 		rq->csd.func = __blk_mq_complete_request_remote;
+ 		rq->csd.info = rq;
+ 		rq->csd.flags = 0;
+ 		smp_call_function_single_async(ctx->cpu, &rq->csd);
++#endif
+ 	} else {
+ 		rq->q->softirq_done_fn(rq);
+ 	}
+-	put_cpu();
++	put_cpu_light();
+ }
+ 
+ void __blk_mq_complete_request(struct request *rq)
+@@ -814,9 +834,9 @@
+ 		    test_bit(BLK_MQ_S_STOPPED, &hctx->state))
+ 			continue;
+ 
+-		preempt_disable();
++		migrate_disable();
+ 		blk_mq_run_hw_queue(hctx, async);
+-		preempt_enable();
++		migrate_enable();
+ 	}
+ }
+ EXPORT_SYMBOL(blk_mq_run_queues);
+@@ -843,9 +863,9 @@
+ {
+ 	clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
+ 
+-	preempt_disable();
++	migrate_disable();
+ 	blk_mq_run_hw_queue(hctx, false);
+-	preempt_enable();
++	migrate_enable();
+ }
+ EXPORT_SYMBOL(blk_mq_start_hw_queue);
+ 
+@@ -870,9 +890,9 @@
+ 			continue;
+ 
+ 		clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
+-		preempt_disable();
++		migrate_disable();
+ 		blk_mq_run_hw_queue(hctx, async);
+-		preempt_enable();
++		migrate_enable();
+ 	}
+ }
+ EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
+@@ -1494,7 +1514,7 @@
+ {
+ 	struct blk_mq_hw_ctx *hctx = data;
+ 
+-	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
++	if (action == CPU_POST_DEAD)
+ 		return blk_mq_hctx_cpu_offline(hctx, cpu);
+ 	else if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
+ 		return blk_mq_hctx_cpu_online(hctx, cpu);
+diff -Nur linux-3.18.8.orig/block/blk-mq-cpu.c linux-3.18.8/block/blk-mq-cpu.c
+--- linux-3.18.8.orig/block/blk-mq-cpu.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-mq-cpu.c	2015-03-03 08:05:17.000000000 +0100
+@@ -16,7 +16,7 @@
+ #include "blk-mq.h"
+ 
+ static LIST_HEAD(blk_mq_cpu_notify_list);
+-static DEFINE_RAW_SPINLOCK(blk_mq_cpu_notify_lock);
++static DEFINE_SPINLOCK(blk_mq_cpu_notify_lock);
+ 
+ static int blk_mq_main_cpu_notify(struct notifier_block *self,
+ 				  unsigned long action, void *hcpu)
+@@ -25,7 +25,10 @@
+ 	struct blk_mq_cpu_notifier *notify;
+ 	int ret = NOTIFY_OK;
+ 
+-	raw_spin_lock(&blk_mq_cpu_notify_lock);
++	if (action != CPU_POST_DEAD)
++		return NOTIFY_OK;
++
++	spin_lock(&blk_mq_cpu_notify_lock);
+ 
+ 	list_for_each_entry(notify, &blk_mq_cpu_notify_list, list) {
+ 		ret = notify->notify(notify->data, action, cpu);
+@@ -33,7 +36,7 @@
+ 			break;
+ 	}
+ 
+-	raw_spin_unlock(&blk_mq_cpu_notify_lock);
++	spin_unlock(&blk_mq_cpu_notify_lock);
+ 	return ret;
+ }
+ 
+@@ -41,16 +44,16 @@
+ {
+ 	BUG_ON(!notifier->notify);
+ 
+-	raw_spin_lock(&blk_mq_cpu_notify_lock);
++	spin_lock(&blk_mq_cpu_notify_lock);
+ 	list_add_tail(&notifier->list, &blk_mq_cpu_notify_list);
+-	raw_spin_unlock(&blk_mq_cpu_notify_lock);
++	spin_unlock(&blk_mq_cpu_notify_lock);
+ }
+ 
+ void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
+ {
+-	raw_spin_lock(&blk_mq_cpu_notify_lock);
++	spin_lock(&blk_mq_cpu_notify_lock);
+ 	list_del(&notifier->list);
+-	raw_spin_unlock(&blk_mq_cpu_notify_lock);
++	spin_unlock(&blk_mq_cpu_notify_lock);
+ }
+ 
+ void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,
+diff -Nur linux-3.18.8.orig/block/blk-mq.h linux-3.18.8/block/blk-mq.h
+--- linux-3.18.8.orig/block/blk-mq.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-mq.h	2015-03-03 08:05:17.000000000 +0100
+@@ -73,7 +73,10 @@
+ static inline struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
+ 					   unsigned int cpu)
+ {
+-	return per_cpu_ptr(q->queue_ctx, cpu);
++	struct blk_mq_ctx *ctx;
++
++	ctx = per_cpu_ptr(q->queue_ctx, cpu);
++	return ctx;
+ }
+ 
+ /*
+@@ -84,12 +87,12 @@
+  */
+ static inline struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
+ {
+-	return __blk_mq_get_ctx(q, get_cpu());
++	return __blk_mq_get_ctx(q, get_cpu_light());
+ }
+ 
+ static inline void blk_mq_put_ctx(struct blk_mq_ctx *ctx)
+ {
+-	put_cpu();
++	put_cpu_light();
+ }
+ 
+ struct blk_mq_alloc_data {
+diff -Nur linux-3.18.8.orig/block/blk-softirq.c linux-3.18.8/block/blk-softirq.c
+--- linux-3.18.8.orig/block/blk-softirq.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/blk-softirq.c	2015-03-03 08:05:17.000000000 +0100
+@@ -51,6 +51,7 @@
+ 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
+ 
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ 
+ /*
+@@ -93,6 +94,7 @@
+ 				 this_cpu_ptr(&blk_cpu_done));
+ 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
+ 		local_irq_enable();
++		preempt_check_resched_rt();
+ 	}
+ 
+ 	return NOTIFY_OK;
+@@ -150,6 +152,7 @@
+ 		goto do_local;
+ 
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ 
+ /**
+diff -Nur linux-3.18.8.orig/block/bounce.c linux-3.18.8/block/bounce.c
+--- linux-3.18.8.orig/block/bounce.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/block/bounce.c	2015-03-03 08:05:17.000000000 +0100
+@@ -54,11 +54,11 @@
+ 	unsigned long flags;
+ 	unsigned char *vto;
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	vto = kmap_atomic(to->bv_page);
+ 	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
+ 	kunmap_atomic(vto);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ }
+ 
+ #else /* CONFIG_HIGHMEM */
+diff -Nur linux-3.18.8.orig/crypto/algapi.c linux-3.18.8/crypto/algapi.c
+--- linux-3.18.8.orig/crypto/algapi.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/crypto/algapi.c	2015-03-03 08:05:17.000000000 +0100
+@@ -698,13 +698,13 @@
+ 
+ int crypto_register_notifier(struct notifier_block *nb)
+ {
+-	return blocking_notifier_chain_register(&crypto_chain, nb);
++	return srcu_notifier_chain_register(&crypto_chain, nb);
+ }
+ EXPORT_SYMBOL_GPL(crypto_register_notifier);
+ 
+ int crypto_unregister_notifier(struct notifier_block *nb)
+ {
+-	return blocking_notifier_chain_unregister(&crypto_chain, nb);
++	return srcu_notifier_chain_unregister(&crypto_chain, nb);
+ }
+ EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
+ 
+diff -Nur linux-3.18.8.orig/crypto/api.c linux-3.18.8/crypto/api.c
+--- linux-3.18.8.orig/crypto/api.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/crypto/api.c	2015-03-03 08:05:17.000000000 +0100
+@@ -31,7 +31,7 @@
+ DECLARE_RWSEM(crypto_alg_sem);
+ EXPORT_SYMBOL_GPL(crypto_alg_sem);
+ 
+-BLOCKING_NOTIFIER_HEAD(crypto_chain);
++SRCU_NOTIFIER_HEAD(crypto_chain);
+ EXPORT_SYMBOL_GPL(crypto_chain);
+ 
+ static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
+@@ -236,10 +236,10 @@
+ {
+ 	int ok;
+ 
+-	ok = blocking_notifier_call_chain(&crypto_chain, val, v);
++	ok = srcu_notifier_call_chain(&crypto_chain, val, v);
+ 	if (ok == NOTIFY_DONE) {
+ 		request_module("cryptomgr");
+-		ok = blocking_notifier_call_chain(&crypto_chain, val, v);
++		ok = srcu_notifier_call_chain(&crypto_chain, val, v);
+ 	}
+ 
+ 	return ok;
+diff -Nur linux-3.18.8.orig/crypto/internal.h linux-3.18.8/crypto/internal.h
+--- linux-3.18.8.orig/crypto/internal.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/crypto/internal.h	2015-03-03 08:05:17.000000000 +0100
+@@ -48,7 +48,7 @@
+ 
+ extern struct list_head crypto_alg_list;
+ extern struct rw_semaphore crypto_alg_sem;
+-extern struct blocking_notifier_head crypto_chain;
++extern struct srcu_notifier_head crypto_chain;
+ 
+ #ifdef CONFIG_PROC_FS
+ void __init crypto_init_proc(void);
+@@ -142,7 +142,7 @@
+ 
+ static inline void crypto_notify(unsigned long val, void *v)
+ {
+-	blocking_notifier_call_chain(&crypto_chain, val, v);
++	srcu_notifier_call_chain(&crypto_chain, val, v);
+ }
+ 
+ #endif	/* _CRYPTO_INTERNAL_H */
+diff -Nur linux-3.18.8.orig/Documentation/hwlat_detector.txt linux-3.18.8/Documentation/hwlat_detector.txt
+--- linux-3.18.8.orig/Documentation/hwlat_detector.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/Documentation/hwlat_detector.txt	2015-03-03 08:05:17.000000000 +0100
+@@ -0,0 +1,64 @@
++Introduction:
++-------------
++
++The module hwlat_detector is a special purpose kernel module that is used to
++detect large system latencies induced by the behavior of certain underlying
++hardware or firmware, independent of Linux itself. The code was developed
++originally to detect SMIs (System Management Interrupts) on x86 systems,
++however there is nothing x86 specific about this patchset. It was
++originally written for use by the "RT" patch since the Real Time
++kernel is highly latency sensitive.
++
++SMIs are usually not serviced by the Linux kernel, which typically does not
++even know that they are occuring. SMIs are instead are set up by BIOS code
++and are serviced by BIOS code, usually for "critical" events such as
++management of thermal sensors and fans. Sometimes though, SMIs are used for
++other tasks and those tasks can spend an inordinate amount of time in the
++handler (sometimes measured in milliseconds). Obviously this is a problem if
++you are trying to keep event service latencies down in the microsecond range.
++
++The hardware latency detector works by hogging all of the cpus for configurable
++amounts of time (by calling stop_machine()), polling the CPU Time Stamp Counter
++for some period, then looking for gaps in the TSC data. Any gap indicates a
++time when the polling was interrupted and since the machine is stopped and
++interrupts turned off the only thing that could do that would be an SMI.
++
++Note that the SMI detector should *NEVER* be used in a production environment.
++It is intended to be run manually to determine if the hardware platform has a
++problem with long system firmware service routines.
++
++Usage:
++------
++
++Loading the module hwlat_detector passing the parameter "enabled=1" (or by
++setting the "enable" entry in "hwlat_detector" debugfs toggled on) is the only
++step required to start the hwlat_detector. It is possible to redefine the
++threshold in microseconds (us) above which latency spikes will be taken
++into account (parameter "threshold=").
++
++Example:
++
++	# modprobe hwlat_detector enabled=1 threshold=100
++
++After the module is loaded, it creates a directory named "hwlat_detector" under
++the debugfs mountpoint, "/debug/hwlat_detector" for this text. It is necessary
++to have debugfs mounted, which might be on /sys/debug on your system.
++
++The /debug/hwlat_detector interface contains the following files:
++
++count			- number of latency spikes observed since last reset
++enable			- a global enable/disable toggle (0/1), resets count
++max			- maximum hardware latency actually observed (usecs)
++sample			- a pipe from which to read current raw sample data
++			  in the format <timestamp> <latency observed usecs>
++			  (can be opened O_NONBLOCK for a single sample)
++threshold		- minimum latency value to be considered (usecs)
++width			- time period to sample with CPUs held (usecs)
++			  must be less than the total window size (enforced)
++window			- total period of sampling, width being inside (usecs)
++
++By default we will set width to 500,000 and window to 1,000,000, meaning that
++we will sample every 1,000,000 usecs (1s) for 500,000 usecs (0.5s). If we
++observe any latencies that exceed the threshold (initially 100 usecs),
++then we write to a global sample ring buffer of 8K samples, which is
++consumed by reading from the "sample" (pipe) debugfs file interface.
+diff -Nur linux-3.18.8.orig/Documentation/sysrq.txt linux-3.18.8/Documentation/sysrq.txt
+--- linux-3.18.8.orig/Documentation/sysrq.txt	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/Documentation/sysrq.txt	2015-03-03 08:05:17.000000000 +0100
+@@ -59,10 +59,17 @@
+ On other - If you know of the key combos for other architectures, please
+            let me know so I can add them to this section.
+ 
+-On all -  write a character to /proc/sysrq-trigger.  e.g.:
+-
++On all -  write a character to /proc/sysrq-trigger, e.g.:
+ 		echo t > /proc/sysrq-trigger
+ 
++On all - Enable network SysRq by writing a cookie to icmp_echo_sysrq, e.g.
++		echo 0x01020304 >/proc/sys/net/ipv4/icmp_echo_sysrq
++	 Send an ICMP echo request with this pattern plus the particular
++	 SysRq command key. Example:
++		# ping -c1 -s57 -p0102030468
++	 will trigger the SysRq-H (help) command.
++
++
+ *  What are the 'command' keys?
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ 'b'     - Will immediately reboot the system without syncing or unmounting
+diff -Nur linux-3.18.8.orig/Documentation/trace/histograms.txt linux-3.18.8/Documentation/trace/histograms.txt
+--- linux-3.18.8.orig/Documentation/trace/histograms.txt	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/Documentation/trace/histograms.txt	2015-03-03 08:05:17.000000000 +0100
+@@ -0,0 +1,186 @@
++		Using the Linux Kernel Latency Histograms
++
++
++This document gives a short explanation how to enable, configure and use
++latency histograms. Latency histograms are primarily relevant in the
++context of real-time enabled kernels (CONFIG_PREEMPT/CONFIG_PREEMPT_RT)
++and are used in the quality management of the Linux real-time
++capabilities.
++
++
++* Purpose of latency histograms
++
++A latency histogram continuously accumulates the frequencies of latency
++data. There are two types of histograms
++- potential sources of latencies
++- effective latencies
++
++
++* Potential sources of latencies
++
++Potential sources of latencies are code segments where interrupts,
++preemption or both are disabled (aka critical sections). To create
++histograms of potential sources of latency, the kernel stores the time
++stamp at the start of a critical section, determines the time elapsed
++when the end of the section is reached, and increments the frequency
++counter of that latency value - irrespective of whether any concurrently
++running process is affected by latency or not.
++- Configuration items (in the Kernel hacking/Tracers submenu)
++  CONFIG_INTERRUPT_OFF_LATENCY
++  CONFIG_PREEMPT_OFF_LATENCY
++
++
++* Effective latencies
++
++Effective latencies are actually occuring during wakeup of a process. To
++determine effective latencies, the kernel stores the time stamp when a
++process is scheduled to be woken up, and determines the duration of the
++wakeup time shortly before control is passed over to this process. Note
++that the apparent latency in user space may be somewhat longer, since the
++process may be interrupted after control is passed over to it but before
++the execution in user space takes place. Simply measuring the interval
++between enqueuing and wakeup may also not appropriate in cases when a
++process is scheduled as a result of a timer expiration. The timer may have
++missed its deadline, e.g. due to disabled interrupts, but this latency
++would not be registered. Therefore, the offsets of missed timers are
++recorded in a separate histogram. If both wakeup latency and missed timer
++offsets are configured and enabled, a third histogram may be enabled that
++records the overall latency as a sum of the timer latency, if any, and the
++wakeup latency. This histogram is called "timerandwakeup".
++- Configuration items (in the Kernel hacking/Tracers submenu)
++  CONFIG_WAKEUP_LATENCY
++  CONFIG_MISSED_TIMER_OFSETS
++
++
++* Usage
++
++The interface to the administration of the latency histograms is located
++in the debugfs file system. To mount it, either enter
++
++mount -t sysfs nodev /sys
++mount -t debugfs nodev /sys/kernel/debug
++
++from shell command line level, or add
++
++nodev	/sys			sysfs	defaults	0 0
++nodev	/sys/kernel/debug	debugfs	defaults	0 0
++
++to the file /etc/fstab. All latency histogram related files are then
++available in the directory /sys/kernel/debug/tracing/latency_hist. A
++particular histogram type is enabled by writing non-zero to the related
++variable in the /sys/kernel/debug/tracing/latency_hist/enable directory.
++Select "preemptirqsoff" for the histograms of potential sources of
++latencies and "wakeup" for histograms of effective latencies etc. The
++histogram data - one per CPU - are available in the files
++
++/sys/kernel/debug/tracing/latency_hist/preemptoff/CPUx
++/sys/kernel/debug/tracing/latency_hist/irqsoff/CPUx
++/sys/kernel/debug/tracing/latency_hist/preemptirqsoff/CPUx
++/sys/kernel/debug/tracing/latency_hist/wakeup/CPUx
++/sys/kernel/debug/tracing/latency_hist/wakeup/sharedprio/CPUx
++/sys/kernel/debug/tracing/latency_hist/missed_timer_offsets/CPUx
++/sys/kernel/debug/tracing/latency_hist/timerandwakeup/CPUx
++
++The histograms are reset by writing non-zero to the file "reset" in a
++particular latency directory. To reset all latency data, use
++
++#!/bin/sh
++
++TRACINGDIR=/sys/kernel/debug/tracing
++HISTDIR=$TRACINGDIR/latency_hist
++
++if test -d $HISTDIR
++then
++  cd $HISTDIR
++  for i in `find . | grep /reset$`
++  do
++    echo 1 >$i
++  done
++fi
++
++
++* Data format
++
++Latency data are stored with a resolution of one microsecond. The
++maximum latency is 10,240 microseconds. The data are only valid, if the
++overflow register is empty. Every output line contains the latency in
++microseconds in the first row and the number of samples in the second
++row. To display only lines with a positive latency count, use, for
++example,
++
++grep -v " 0$" /sys/kernel/debug/tracing/latency_hist/preemptoff/CPU0
++
++#Minimum latency: 0 microseconds.
++#Average latency: 0 microseconds.
++#Maximum latency: 25 microseconds.
++#Total samples: 3104770694
++#There are 0 samples greater or equal than 10240 microseconds
++#usecs	         samples
++    0	      2984486876
++    1	        49843506
++    2	        58219047
++    3	         5348126
++    4	         2187960
++    5	         3388262
++    6	          959289
++    7	          208294
++    8	           40420
++    9	            4485
++   10	           14918
++   11	           18340
++   12	           25052
++   13	           19455
++   14	            5602
++   15	             969
++   16	              47
++   17	              18
++   18	              14
++   19	               1
++   20	               3
++   21	               2
++   22	               5
++   23	               2
++   25	               1
++
++
++* Wakeup latency of a selected process
++
++To only collect wakeup latency data of a particular process, write the
++PID of the requested process to
++
++/sys/kernel/debug/tracing/latency_hist/wakeup/pid
++
++PIDs are not considered, if this variable is set to 0.
++
++
++* Details of the process with the highest wakeup latency so far
++
++Selected data of the process that suffered from the highest wakeup
++latency that occurred in a particular CPU are available in the file
++
++/sys/kernel/debug/tracing/latency_hist/wakeup/max_latency-CPUx.
++
++In addition, other relevant system data at the time when the
++latency occurred are given.
++
++The format of the data is (all in one line):
++<PID> <Priority> <Latency> (<Timeroffset>) <Command> \
++<- <PID> <Priority> <Command> <Timestamp>
++
++The value of <Timeroffset> is only relevant in the combined timer
++and wakeup latency recording. In the wakeup recording, it is
++always 0, in the missed_timer_offsets recording, it is the same
++as <Latency>.
++
++When retrospectively searching for the origin of a latency and
++tracing was not enabled, it may be helpful to know the name and
++some basic data of the task that (finally) was switching to the
++late real-tlme task. In addition to the victim's data, also the
++data of the possible culprit are therefore displayed after the
++"<-" symbol.
++
++Finally, the timestamp of the time when the latency occurred
++in <seconds>.<microseconds> after the most recent system boot
++is provided.
++
++These data are also reset when the wakeup histogram is reset.
+diff -Nur linux-3.18.8.orig/drivers/acpi/acpica/acglobal.h linux-3.18.8/drivers/acpi/acpica/acglobal.h
+--- linux-3.18.8.orig/drivers/acpi/acpica/acglobal.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/acpi/acpica/acglobal.h	2015-03-03 08:05:17.000000000 +0100
+@@ -112,7 +112,7 @@
+  * interrupt level
+  */
+ ACPI_GLOBAL(acpi_spinlock, acpi_gbl_gpe_lock);	/* For GPE data structs and registers */
+-ACPI_GLOBAL(acpi_spinlock, acpi_gbl_hardware_lock);	/* For ACPI H/W except GPE registers */
++ACPI_GLOBAL(acpi_raw_spinlock, acpi_gbl_hardware_lock);	/* For ACPI H/W except GPE registers */
+ ACPI_GLOBAL(acpi_spinlock, acpi_gbl_reference_count_lock);
+ 
+ /* Mutex for _OSI support */
+diff -Nur linux-3.18.8.orig/drivers/acpi/acpica/hwregs.c linux-3.18.8/drivers/acpi/acpica/hwregs.c
+--- linux-3.18.8.orig/drivers/acpi/acpica/hwregs.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/acpi/acpica/hwregs.c	2015-03-03 08:05:17.000000000 +0100
+@@ -269,14 +269,14 @@
+ 			  ACPI_BITMASK_ALL_FIXED_STATUS,
+ 			  ACPI_FORMAT_UINT64(acpi_gbl_xpm1a_status.address)));
+ 
+-	lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
++	raw_spin_lock_irqsave(acpi_gbl_hardware_lock, lock_flags);
+ 
+ 	/* Clear the fixed events in PM1 A/B */
+ 
+ 	status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
+ 					ACPI_BITMASK_ALL_FIXED_STATUS);
+ 
+-	acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
++	raw_spin_unlock_irqrestore(acpi_gbl_hardware_lock, lock_flags);
+ 
+ 	if (ACPI_FAILURE(status)) {
+ 		goto exit;
+diff -Nur linux-3.18.8.orig/drivers/acpi/acpica/hwxface.c linux-3.18.8/drivers/acpi/acpica/hwxface.c
+--- linux-3.18.8.orig/drivers/acpi/acpica/hwxface.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/acpi/acpica/hwxface.c	2015-03-03 08:05:17.000000000 +0100
+@@ -374,7 +374,7 @@
+ 		return_ACPI_STATUS(AE_BAD_PARAMETER);
+ 	}
+ 
+-	lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
++	raw_spin_lock_irqsave(acpi_gbl_hardware_lock, lock_flags);
+ 
+ 	/*
+ 	 * At this point, we know that the parent register is one of the
+@@ -435,7 +435,7 @@
+ 
+ unlock_and_exit:
+ 
+-	acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
++	raw_spin_unlock_irqrestore(acpi_gbl_hardware_lock, lock_flags);
+ 	return_ACPI_STATUS(status);
+ }
+ 
+diff -Nur linux-3.18.8.orig/drivers/acpi/acpica/utmutex.c linux-3.18.8/drivers/acpi/acpica/utmutex.c
+--- linux-3.18.8.orig/drivers/acpi/acpica/utmutex.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/acpi/acpica/utmutex.c	2015-03-03 08:05:17.000000000 +0100
+@@ -88,7 +88,7 @@
+ 		return_ACPI_STATUS (status);
+ 	}
+ 
+-	status = acpi_os_create_lock (&acpi_gbl_hardware_lock);
++	status = acpi_os_create_raw_lock (&acpi_gbl_hardware_lock);
+ 	if (ACPI_FAILURE (status)) {
+ 		return_ACPI_STATUS (status);
+ 	}
+@@ -141,7 +141,7 @@
+ 	/* Delete the spinlocks */
+ 
+ 	acpi_os_delete_lock(acpi_gbl_gpe_lock);
+-	acpi_os_delete_lock(acpi_gbl_hardware_lock);
++	acpi_os_delete_raw_lock(acpi_gbl_hardware_lock);
+ 	acpi_os_delete_lock(acpi_gbl_reference_count_lock);
+ 
+ 	/* Delete the reader/writer lock */
+diff -Nur linux-3.18.8.orig/drivers/ata/libata-sff.c linux-3.18.8/drivers/ata/libata-sff.c
+--- linux-3.18.8.orig/drivers/ata/libata-sff.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ata/libata-sff.c	2015-03-03 08:05:17.000000000 +0100
+@@ -678,9 +678,9 @@
+ 	unsigned long flags;
+ 	unsigned int consumed;
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	consumed = ata_sff_data_xfer32(dev, buf, buflen, rw);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	return consumed;
+ }
+@@ -719,7 +719,7 @@
+ 		unsigned long flags;
+ 
+ 		/* FIXME: use a bounce buffer */
+-		local_irq_save(flags);
++		local_irq_save_nort(flags);
+ 		buf = kmap_atomic(page);
+ 
+ 		/* do the actual data transfer */
+@@ -727,7 +727,7 @@
+ 				       do_write);
+ 
+ 		kunmap_atomic(buf);
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 	} else {
+ 		buf = page_address(page);
+ 		ap->ops->sff_data_xfer(qc->dev, buf + offset, qc->sect_size,
+@@ -864,7 +864,7 @@
+ 		unsigned long flags;
+ 
+ 		/* FIXME: use bounce buffer */
+-		local_irq_save(flags);
++		local_irq_save_nort(flags);
+ 		buf = kmap_atomic(page);
+ 
+ 		/* do the actual data transfer */
+@@ -872,7 +872,7 @@
+ 								count, rw);
+ 
+ 		kunmap_atomic(buf);
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 	} else {
+ 		buf = page_address(page);
+ 		consumed = ap->ops->sff_data_xfer(dev,  buf + offset,
+diff -Nur linux-3.18.8.orig/drivers/char/random.c linux-3.18.8/drivers/char/random.c
+--- linux-3.18.8.orig/drivers/char/random.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/char/random.c	2015-03-03 08:05:17.000000000 +0100
+@@ -776,8 +776,6 @@
+ 	} sample;
+ 	long delta, delta2, delta3;
+ 
+-	preempt_disable();
+-
+ 	sample.jiffies = jiffies;
+ 	sample.cycles = random_get_entropy();
+ 	sample.num = num;
+@@ -818,7 +816,6 @@
+ 		 */
+ 		credit_entropy_bits(r, min_t(int, fls(delta>>1), 11));
+ 	}
+-	preempt_enable();
+ }
+ 
+ void add_input_randomness(unsigned int type, unsigned int code,
+@@ -871,28 +868,27 @@
+ 	return *(ptr + f->reg_idx++);
+ }
+ 
+-void add_interrupt_randomness(int irq, int irq_flags)
++void add_interrupt_randomness(int irq, int irq_flags, __u64 ip)
+ {
+ 	struct entropy_store	*r;
+ 	struct fast_pool	*fast_pool = this_cpu_ptr(&irq_randomness);
+-	struct pt_regs		*regs = get_irq_regs();
+ 	unsigned long		now = jiffies;
+ 	cycles_t		cycles = random_get_entropy();
+ 	__u32			c_high, j_high;
+-	__u64			ip;
+ 	unsigned long		seed;
+ 	int			credit = 0;
+ 
+ 	if (cycles == 0)
+-		cycles = get_reg(fast_pool, regs);
++		cycles = get_reg(fast_pool, NULL);
+ 	c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0;
+ 	j_high = (sizeof(now) > 4) ? now >> 32 : 0;
+ 	fast_pool->pool[0] ^= cycles ^ j_high ^ irq;
+ 	fast_pool->pool[1] ^= now ^ c_high;
+-	ip = regs ? instruction_pointer(regs) : _RET_IP_;
++	if (!ip)
++		ip = _RET_IP_;
+ 	fast_pool->pool[2] ^= ip;
+ 	fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 :
+-		get_reg(fast_pool, regs);
++		get_reg(fast_pool, NULL);
+ 
+ 	fast_mix(fast_pool);
+ 	add_interrupt_bench(cycles);
+diff -Nur linux-3.18.8.orig/drivers/clocksource/tcb_clksrc.c linux-3.18.8/drivers/clocksource/tcb_clksrc.c
+--- linux-3.18.8.orig/drivers/clocksource/tcb_clksrc.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/clocksource/tcb_clksrc.c	2015-03-03 08:05:17.000000000 +0100
+@@ -23,8 +23,7 @@
+  *     this 32 bit free-running counter. the second channel is not used.
+  *
+  *   - The third channel may be used to provide a 16-bit clockevent
+- *     source, used in either periodic or oneshot mode.  This runs
+- *     at 32 KiHZ, and can handle delays of up to two seconds.
++ *     source, used in either periodic or oneshot mode.
+  *
+  * A boot clocksource and clockevent source are also currently needed,
+  * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
+@@ -74,6 +73,7 @@
+ struct tc_clkevt_device {
+ 	struct clock_event_device	clkevt;
+ 	struct clk			*clk;
++	u32				freq;
+ 	void __iomem			*regs;
+ };
+ 
+@@ -82,13 +82,6 @@
+ 	return container_of(clkevt, struct tc_clkevt_device, clkevt);
+ }
+ 
+-/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
+- * because using one of the divided clocks would usually mean the
+- * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
+- *
+- * A divided clock could be good for high resolution timers, since
+- * 30.5 usec resolution can seem "low".
+- */
+ static u32 timer_clock;
+ 
+ static void tc_mode(enum clock_event_mode m, struct clock_event_device *d)
+@@ -111,11 +104,12 @@
+ 	case CLOCK_EVT_MODE_PERIODIC:
+ 		clk_enable(tcd->clk);
+ 
+-		/* slow clock, count up to RC, then irq and restart */
++		/* count up to RC, then irq and restart */
+ 		__raw_writel(timer_clock
+ 				| ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
+ 				regs + ATMEL_TC_REG(2, CMR));
+-		__raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
++		__raw_writel((tcd->freq + HZ / 2) / HZ,
++			     tcaddr + ATMEL_TC_REG(2, RC));
+ 
+ 		/* Enable clock and interrupts on RC compare */
+ 		__raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
+@@ -128,7 +122,7 @@
+ 	case CLOCK_EVT_MODE_ONESHOT:
+ 		clk_enable(tcd->clk);
+ 
+-		/* slow clock, count up to RC, then irq and stop */
++		/* count up to RC, then irq and stop */
+ 		__raw_writel(timer_clock | ATMEL_TC_CPCSTOP
+ 				| ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
+ 				regs + ATMEL_TC_REG(2, CMR));
+@@ -157,8 +151,12 @@
+ 		.name		= "tc_clkevt",
+ 		.features	= CLOCK_EVT_FEAT_PERIODIC
+ 					| CLOCK_EVT_FEAT_ONESHOT,
++#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
+ 		/* Should be lower than at91rm9200's system timer */
+ 		.rating		= 125,
++#else
++		.rating		= 200,
++#endif
+ 		.set_next_event	= tc_next_event,
+ 		.set_mode	= tc_mode,
+ 	},
+@@ -178,8 +176,9 @@
+ 	return IRQ_NONE;
+ }
+ 
+-static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
++static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx)
+ {
++	unsigned divisor = atmel_tc_divisors[divisor_idx];
+ 	int ret;
+ 	struct clk *t2_clk = tc->clk[2];
+ 	int irq = tc->irq[2];
+@@ -193,7 +192,11 @@
+ 	clkevt.regs = tc->regs;
+ 	clkevt.clk = t2_clk;
+ 
+-	timer_clock = clk32k_divisor_idx;
++	timer_clock = divisor_idx;
++	if (!divisor)
++		clkevt.freq = 32768;
++	else
++		clkevt.freq = clk_get_rate(t2_clk) / divisor;
+ 
+ 	clkevt.clkevt.cpumask = cpumask_of(0);
+ 
+@@ -203,7 +206,7 @@
+ 		return ret;
+ 	}
+ 
+-	clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
++	clockevents_config_and_register(&clkevt.clkevt, clkevt.freq, 1, 0xffff);
+ 
+ 	return ret;
+ }
+@@ -340,7 +343,11 @@
+ 		goto err_disable_t1;
+ 
+ 	/* channel 2:  periodic and oneshot timer support */
++#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
+ 	ret = setup_clkevents(tc, clk32k_divisor_idx);
++#else
++	ret = setup_clkevents(tc, best_divisor_idx);
++#endif
+ 	if (ret)
+ 		goto err_unregister_clksrc;
+ 
+diff -Nur linux-3.18.8.orig/drivers/clocksource/timer-atmel-pit.c linux-3.18.8/drivers/clocksource/timer-atmel-pit.c
+--- linux-3.18.8.orig/drivers/clocksource/timer-atmel-pit.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/clocksource/timer-atmel-pit.c	2015-03-03 08:05:17.000000000 +0100
+@@ -90,6 +90,7 @@
+ 	return elapsed;
+ }
+ 
++static struct irqaction at91sam926x_pit_irq;
+ /*
+  * Clockevent device:  interrupts every 1/HZ (== pit_cycles * MCK/16)
+  */
+@@ -100,6 +101,8 @@
+ 
+ 	switch (mode) {
+ 	case CLOCK_EVT_MODE_PERIODIC:
++		/* Set up irq handler */
++		setup_irq(at91sam926x_pit_irq.irq, &at91sam926x_pit_irq);
+ 		/* update clocksource counter */
+ 		data->cnt += data->cycle * PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
+ 		pit_write(data->base, AT91_PIT_MR,
+@@ -113,6 +116,7 @@
+ 		/* disable irq, leaving the clocksource active */
+ 		pit_write(data->base, AT91_PIT_MR,
+ 			  (data->cycle - 1) | AT91_PIT_PITEN);
++		remove_irq(at91sam926x_pit_irq.irq, &at91sam926x_pit_irq);
+ 		break;
+ 	case CLOCK_EVT_MODE_RESUME:
+ 		break;
+diff -Nur linux-3.18.8.orig/drivers/gpio/gpio-omap.c linux-3.18.8/drivers/gpio/gpio-omap.c
+--- linux-3.18.8.orig/drivers/gpio/gpio-omap.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/gpio/gpio-omap.c	2015-03-03 08:05:17.000000000 +0100
+@@ -57,7 +57,7 @@
+ 	u32 saved_datain;
+ 	u32 level_mask;
+ 	u32 toggle_mask;
+-	spinlock_t lock;
++	raw_spinlock_t lock;
+ 	struct gpio_chip chip;
+ 	struct clk *dbck;
+ 	u32 mod_usage;
+@@ -503,19 +503,19 @@
+ 		(type & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH)))
+ 		return -EINVAL;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	offset = GPIO_INDEX(bank, gpio);
+ 	retval = omap_set_gpio_triggering(bank, offset, type);
+ 	if (!LINE_USED(bank->mod_usage, offset)) {
+ 		omap_enable_gpio_module(bank, offset);
+ 		omap_set_gpio_direction(bank, offset, 1);
+ 	} else if (!omap_gpio_is_input(bank, BIT(offset))) {
+-		spin_unlock_irqrestore(&bank->lock, flags);
++		raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 		return -EINVAL;
+ 	}
+ 
+ 	bank->irq_usage |= BIT(GPIO_INDEX(bank, gpio));
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
+ 		__irq_set_handler_locked(d->irq, handle_level_irq);
+@@ -633,14 +633,14 @@
+ 		return -EINVAL;
+ 	}
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	if (enable)
+ 		bank->context.wake_en |= gpio_bit;
+ 	else
+ 		bank->context.wake_en &= ~gpio_bit;
+ 
+ 	writel_relaxed(bank->context.wake_en, bank->base + bank->regs->wkup_en);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+@@ -675,7 +675,7 @@
+ 	if (!BANK_USED(bank))
+ 		pm_runtime_get_sync(bank->dev);
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	/* Set trigger to none. You need to enable the desired trigger with
+ 	 * request_irq() or set_irq_type(). Only do this if the IRQ line has
+ 	 * not already been requested.
+@@ -685,7 +685,7 @@
+ 		omap_enable_gpio_module(bank, offset);
+ 	}
+ 	bank->mod_usage |= BIT(offset);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+@@ -695,11 +695,11 @@
+ 	struct gpio_bank *bank = container_of(chip, struct gpio_bank, chip);
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	bank->mod_usage &= ~(BIT(offset));
+ 	omap_disable_gpio_module(bank, offset);
+ 	omap_reset_gpio(bank, bank->chip.base + offset);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	/*
+ 	 * If this is the last gpio to be freed in the bank,
+@@ -799,12 +799,12 @@
+ 	unsigned long flags;
+ 	unsigned offset = GPIO_INDEX(bank, gpio);
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	gpio_unlock_as_irq(&bank->chip, offset);
+ 	bank->irq_usage &= ~(BIT(offset));
+ 	omap_disable_gpio_module(bank, offset);
+ 	omap_reset_gpio(bank, gpio);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	/*
+ 	 * If this is the last IRQ to be freed in the bank,
+@@ -828,10 +828,10 @@
+ 	unsigned int gpio = omap_irq_to_gpio(bank, d->hwirq);
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	omap_set_gpio_irqenable(bank, gpio, 0);
+ 	omap_set_gpio_triggering(bank, GPIO_INDEX(bank, gpio), IRQ_TYPE_NONE);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ }
+ 
+ static void omap_gpio_unmask_irq(struct irq_data *d)
+@@ -842,7 +842,7 @@
+ 	u32 trigger = irqd_get_trigger_type(d);
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	if (trigger)
+ 		omap_set_gpio_triggering(bank, GPIO_INDEX(bank, gpio), trigger);
+ 
+@@ -854,7 +854,7 @@
+ 	}
+ 
+ 	omap_set_gpio_irqenable(bank, gpio, 1);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ }
+ 
+ /*---------------------------------------------------------------------*/
+@@ -867,9 +867,9 @@
+ 					OMAP_MPUIO_GPIO_MASKIT / bank->stride;
+ 	unsigned long		flags;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	writel_relaxed(0xffff & ~bank->context.wake_en, mask_reg);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+@@ -882,9 +882,9 @@
+ 					OMAP_MPUIO_GPIO_MASKIT / bank->stride;
+ 	unsigned long		flags;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	writel_relaxed(bank->context.wake_en, mask_reg);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+@@ -930,9 +930,9 @@
+ 
+ 	bank = container_of(chip, struct gpio_bank, chip);
+ 	reg = bank->base + bank->regs->direction;
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	dir = !!(readl_relaxed(reg) & BIT(offset));
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 	return dir;
+ }
+ 
+@@ -942,9 +942,9 @@
+ 	unsigned long flags;
+ 
+ 	bank = container_of(chip, struct gpio_bank, chip);
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	omap_set_gpio_direction(bank, offset, 1);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 	return 0;
+ }
+ 
+@@ -968,10 +968,10 @@
+ 	unsigned long flags;
+ 
+ 	bank = container_of(chip, struct gpio_bank, chip);
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	bank->set_dataout(bank, offset, value);
+ 	omap_set_gpio_direction(bank, offset, 0);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 	return 0;
+ }
+ 
+@@ -983,9 +983,9 @@
+ 
+ 	bank = container_of(chip, struct gpio_bank, chip);
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	omap2_set_gpio_debounce(bank, offset, debounce);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+@@ -996,9 +996,9 @@
+ 	unsigned long flags;
+ 
+ 	bank = container_of(chip, struct gpio_bank, chip);
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 	bank->set_dataout(bank, offset, value);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ }
+ 
+ /*---------------------------------------------------------------------*/
+@@ -1223,7 +1223,7 @@
+ 	else
+ 		bank->set_dataout = omap_set_gpio_dataout_mask;
+ 
+-	spin_lock_init(&bank->lock);
++	raw_spin_lock_init(&bank->lock);
+ 
+ 	/* Static mapping, never released */
+ 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+@@ -1270,7 +1270,7 @@
+ 	unsigned long flags;
+ 	u32 wake_low, wake_hi;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 
+ 	/*
+ 	 * Only edges can generate a wakeup event to the PRCM.
+@@ -1323,7 +1323,7 @@
+ 				bank->get_context_loss_count(bank->dev);
+ 
+ 	omap_gpio_dbck_disable(bank);
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+@@ -1338,7 +1338,7 @@
+ 	unsigned long flags;
+ 	int c;
+ 
+-	spin_lock_irqsave(&bank->lock, flags);
++	raw_spin_lock_irqsave(&bank->lock, flags);
+ 
+ 	/*
+ 	 * On the first resume during the probe, the context has not
+@@ -1374,14 +1374,14 @@
+ 			if (c != bank->context_loss_count) {
+ 				omap_gpio_restore_context(bank);
+ 			} else {
+-				spin_unlock_irqrestore(&bank->lock, flags);
++				raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 				return 0;
+ 			}
+ 		}
+ 	}
+ 
+ 	if (!bank->workaround_enabled) {
+-		spin_unlock_irqrestore(&bank->lock, flags);
++		raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 		return 0;
+ 	}
+ 
+@@ -1436,7 +1436,7 @@
+ 	}
+ 
+ 	bank->workaround_enabled = false;
+-	spin_unlock_irqrestore(&bank->lock, flags);
++	raw_spin_unlock_irqrestore(&bank->lock, flags);
+ 
+ 	return 0;
+ }
+diff -Nur linux-3.18.8.orig/drivers/gpu/drm/i915/i915_gem.c linux-3.18.8/drivers/gpu/drm/i915/i915_gem.c
+--- linux-3.18.8.orig/drivers/gpu/drm/i915/i915_gem.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/gpu/drm/i915/i915_gem.c	2015-03-03 08:05:17.000000000 +0100
+@@ -5144,7 +5144,7 @@
+ 	if (!mutex_is_locked(mutex))
+ 		return false;
+ 
+-#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES)
++#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES) && !defined(CONFIG_PREEMPT_RT_BASE)
+ 	return mutex->owner == task;
+ #else
+ 	/* Since UP may be pre-empted, we cannot assume that we own the lock */
+diff -Nur linux-3.18.8.orig/drivers/gpu/drm/i915/i915_gem_execbuffer.c linux-3.18.8/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+--- linux-3.18.8.orig/drivers/gpu/drm/i915/i915_gem_execbuffer.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/gpu/drm/i915/i915_gem_execbuffer.c	2015-03-03 08:05:17.000000000 +0100
+@@ -1170,7 +1170,9 @@
+ 			return ret;
+ 	}
+ 
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	trace_i915_gem_ring_dispatch(ring, intel_ring_get_seqno(ring), flags);
++#endif
+ 
+ 	i915_gem_execbuffer_move_to_active(vmas, ring);
+ 	i915_gem_execbuffer_retire_commands(dev, file, ring, batch_obj);
+diff -Nur linux-3.18.8.orig/drivers/i2c/busses/i2c-omap.c linux-3.18.8/drivers/i2c/busses/i2c-omap.c
+--- linux-3.18.8.orig/drivers/i2c/busses/i2c-omap.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/i2c/busses/i2c-omap.c	2015-03-03 08:05:17.000000000 +0100
+@@ -875,15 +875,12 @@
+ 	u16 mask;
+ 	u16 stat;
+ 
+-	spin_lock(&dev->lock);
+-	mask = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
+ 	stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
++	mask = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
+ 
+ 	if (stat & mask)
+ 		ret = IRQ_WAKE_THREAD;
+ 
+-	spin_unlock(&dev->lock);
+-
+ 	return ret;
+ }
+ 
+diff -Nur linux-3.18.8.orig/drivers/ide/alim15x3.c linux-3.18.8/drivers/ide/alim15x3.c
+--- linux-3.18.8.orig/drivers/ide/alim15x3.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/alim15x3.c	2015-03-03 08:05:17.000000000 +0100
+@@ -234,7 +234,7 @@
+ 
+ 	isa_dev = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL);
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 
+ 	if (m5229_revision < 0xC2) {
+ 		/*
+@@ -325,7 +325,7 @@
+ 	}
+ 	pci_dev_put(north);
+ 	pci_dev_put(isa_dev);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 	return 0;
+ }
+ 
+diff -Nur linux-3.18.8.orig/drivers/ide/hpt366.c linux-3.18.8/drivers/ide/hpt366.c
+--- linux-3.18.8.orig/drivers/ide/hpt366.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/hpt366.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1241,7 +1241,7 @@
+ 
+ 	dma_old = inb(base + 2);
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 
+ 	dma_new = dma_old;
+ 	pci_read_config_byte(dev, hwif->channel ? 0x4b : 0x43, &masterdma);
+@@ -1252,7 +1252,7 @@
+ 	if (dma_new != dma_old)
+ 		outb(dma_new, base + 2);
+ 
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	printk(KERN_INFO "    %s: BM-DMA at 0x%04lx-0x%04lx\n",
+ 			 hwif->name, base, base + 7);
+diff -Nur linux-3.18.8.orig/drivers/ide/ide-io.c linux-3.18.8/drivers/ide/ide-io.c
+--- linux-3.18.8.orig/drivers/ide/ide-io.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/ide-io.c	2015-03-03 08:05:18.000000000 +0100
+@@ -659,7 +659,7 @@
+ 		/* disable_irq_nosync ?? */
+ 		disable_irq(hwif->irq);
+ 		/* local CPU only, as if we were handling an interrupt */
+-		local_irq_disable();
++		local_irq_disable_nort();
+ 		if (hwif->polling) {
+ 			startstop = handler(drive);
+ 		} else if (drive_is_ready(drive)) {
+diff -Nur linux-3.18.8.orig/drivers/ide/ide-iops.c linux-3.18.8/drivers/ide/ide-iops.c
+--- linux-3.18.8.orig/drivers/ide/ide-iops.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/ide-iops.c	2015-03-03 08:05:18.000000000 +0100
+@@ -129,12 +129,12 @@
+ 				if ((stat & ATA_BUSY) == 0)
+ 					break;
+ 
+-				local_irq_restore(flags);
++				local_irq_restore_nort(flags);
+ 				*rstat = stat;
+ 				return -EBUSY;
+ 			}
+ 		}
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 	}
+ 	/*
+ 	 * Allow status to settle, then read it again.
+diff -Nur linux-3.18.8.orig/drivers/ide/ide-io-std.c linux-3.18.8/drivers/ide/ide-io-std.c
+--- linux-3.18.8.orig/drivers/ide/ide-io-std.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/ide-io-std.c	2015-03-03 08:05:18.000000000 +0100
+@@ -175,7 +175,7 @@
+ 		unsigned long uninitialized_var(flags);
+ 
+ 		if ((io_32bit & 2) && !mmio) {
+-			local_irq_save(flags);
++			local_irq_save_nort(flags);
+ 			ata_vlb_sync(io_ports->nsect_addr);
+ 		}
+ 
+@@ -186,7 +186,7 @@
+ 			insl(data_addr, buf, words);
+ 
+ 		if ((io_32bit & 2) && !mmio)
+-			local_irq_restore(flags);
++			local_irq_restore_nort(flags);
+ 
+ 		if (((len + 1) & 3) < 2)
+ 			return;
+@@ -219,7 +219,7 @@
+ 		unsigned long uninitialized_var(flags);
+ 
+ 		if ((io_32bit & 2) && !mmio) {
+-			local_irq_save(flags);
++			local_irq_save_nort(flags);
+ 			ata_vlb_sync(io_ports->nsect_addr);
+ 		}
+ 
+@@ -230,7 +230,7 @@
+ 			outsl(data_addr, buf, words);
+ 
+ 		if ((io_32bit & 2) && !mmio)
+-			local_irq_restore(flags);
++			local_irq_restore_nort(flags);
+ 
+ 		if (((len + 1) & 3) < 2)
+ 			return;
+diff -Nur linux-3.18.8.orig/drivers/ide/ide-probe.c linux-3.18.8/drivers/ide/ide-probe.c
+--- linux-3.18.8.orig/drivers/ide/ide-probe.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/ide-probe.c	2015-03-03 08:05:18.000000000 +0100
+@@ -196,10 +196,10 @@
+ 	int bswap = 1;
+ 
+ 	/* local CPU only; some systems need this */
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	/* read 512 bytes of id info */
+ 	hwif->tp_ops->input_data(drive, NULL, id, SECTOR_SIZE);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	drive->dev_flags |= IDE_DFLAG_ID_READ;
+ #ifdef DEBUG
+diff -Nur linux-3.18.8.orig/drivers/ide/ide-taskfile.c linux-3.18.8/drivers/ide/ide-taskfile.c
+--- linux-3.18.8.orig/drivers/ide/ide-taskfile.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/ide/ide-taskfile.c	2015-03-03 08:05:18.000000000 +0100
+@@ -250,7 +250,7 @@
+ 
+ 		page_is_high = PageHighMem(page);
+ 		if (page_is_high)
+-			local_irq_save(flags);
++			local_irq_save_nort(flags);
+ 
+ 		buf = kmap_atomic(page) + offset;
+ 
+@@ -271,7 +271,7 @@
+ 		kunmap_atomic(buf);
+ 
+ 		if (page_is_high)
+-			local_irq_restore(flags);
++			local_irq_restore_nort(flags);
+ 
+ 		len -= nr_bytes;
+ 	}
+@@ -414,7 +414,7 @@
+ 	}
+ 
+ 	if ((drive->dev_flags & IDE_DFLAG_UNMASK) == 0)
+-		local_irq_disable();
++		local_irq_disable_nort();
+ 
+ 	ide_set_handler(drive, &task_pio_intr, WAIT_WORSTCASE);
+ 
+diff -Nur linux-3.18.8.orig/drivers/infiniband/ulp/ipoib/ipoib_multicast.c linux-3.18.8/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+--- linux-3.18.8.orig/drivers/infiniband/ulp/ipoib/ipoib_multicast.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/infiniband/ulp/ipoib/ipoib_multicast.c	2015-03-03 08:05:18.000000000 +0100
+@@ -796,7 +796,7 @@
+ 
+ 	ipoib_mcast_stop_thread(dev, 0);
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	netif_addr_lock(dev);
+ 	spin_lock(&priv->lock);
+ 
+@@ -878,7 +878,7 @@
+ 
+ 	spin_unlock(&priv->lock);
+ 	netif_addr_unlock(dev);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	/* We have to cancel outside of the spinlock */
+ 	list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
+diff -Nur linux-3.18.8.orig/drivers/input/gameport/gameport.c linux-3.18.8/drivers/input/gameport/gameport.c
+--- linux-3.18.8.orig/drivers/input/gameport/gameport.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/input/gameport/gameport.c	2015-03-03 08:05:18.000000000 +0100
+@@ -124,12 +124,12 @@
+ 	tx = 1 << 30;
+ 
+ 	for(i = 0; i < 50; i++) {
+-		local_irq_save(flags);
++		local_irq_save_nort(flags);
+ 		GET_TIME(t1);
+ 		for (t = 0; t < 50; t++) gameport_read(gameport);
+ 		GET_TIME(t2);
+ 		GET_TIME(t3);
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 		udelay(i * 10);
+ 		if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
+ 	}
+@@ -148,11 +148,11 @@
+ 	tx = 1 << 30;
+ 
+ 	for(i = 0; i < 50; i++) {
+-		local_irq_save(flags);
++		local_irq_save_nort(flags);
+ 		rdtscl(t1);
+ 		for (t = 0; t < 50; t++) gameport_read(gameport);
+ 		rdtscl(t2);
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 		udelay(i * 10);
+ 		if (t2 - t1 < tx) tx = t2 - t1;
+ 	}
+diff -Nur linux-3.18.8.orig/drivers/leds/trigger/Kconfig linux-3.18.8/drivers/leds/trigger/Kconfig
+--- linux-3.18.8.orig/drivers/leds/trigger/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/leds/trigger/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -61,7 +61,7 @@
+ 
+ config LEDS_TRIGGER_CPU
+ 	bool "LED CPU Trigger"
+-	depends on LEDS_TRIGGERS
++	depends on LEDS_TRIGGERS && !PREEMPT_RT_BASE
+ 	help
+ 	  This allows LEDs to be controlled by active CPUs. This shows
+ 	  the active CPUs across an array of LEDs so you can see which
+diff -Nur linux-3.18.8.orig/drivers/md/bcache/Kconfig linux-3.18.8/drivers/md/bcache/Kconfig
+--- linux-3.18.8.orig/drivers/md/bcache/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/md/bcache/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -1,6 +1,7 @@
+ 
+ config BCACHE
+ 	tristate "Block device as cache"
++	depends on !PREEMPT_RT_FULL
+ 	---help---
+ 	Allows a block device to be used as cache for other devices; uses
+ 	a btree for indexing and the layout is optimized for SSDs.
+diff -Nur linux-3.18.8.orig/drivers/md/dm.c linux-3.18.8/drivers/md/dm.c
+--- linux-3.18.8.orig/drivers/md/dm.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/md/dm.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1898,14 +1898,14 @@
+ 		if (map_request(ti, clone, md))
+ 			goto requeued;
+ 
+-		BUG_ON(!irqs_disabled());
++		BUG_ON_NONRT(!irqs_disabled());
+ 		spin_lock(q->queue_lock);
+ 	}
+ 
+ 	goto out;
+ 
+ requeued:
+-	BUG_ON(!irqs_disabled());
++	BUG_ON_NONRT(!irqs_disabled());
+ 	spin_lock(q->queue_lock);
+ 
+ delay_and_out:
+diff -Nur linux-3.18.8.orig/drivers/md/raid5.c linux-3.18.8/drivers/md/raid5.c
+--- linux-3.18.8.orig/drivers/md/raid5.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/md/raid5.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1649,8 +1649,9 @@
+ 	struct raid5_percpu *percpu;
+ 	unsigned long cpu;
+ 
+-	cpu = get_cpu();
++	cpu = get_cpu_light();
+ 	percpu = per_cpu_ptr(conf->percpu, cpu);
++	spin_lock(&percpu->lock);
+ 	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
+ 		ops_run_biofill(sh);
+ 		overlap_clear++;
+@@ -1702,7 +1703,8 @@
+ 			if (test_and_clear_bit(R5_Overlap, &dev->flags))
+ 				wake_up(&sh->raid_conf->wait_for_overlap);
+ 		}
+-	put_cpu();
++	spin_unlock(&percpu->lock);
++	put_cpu_light();
+ }
+ 
+ static int grow_one_stripe(struct r5conf *conf, int hash)
+@@ -5707,6 +5709,7 @@
+ 			       __func__, cpu);
+ 			break;
+ 		}
++		spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
+ 	}
+ 	put_online_cpus();
+ 
+diff -Nur linux-3.18.8.orig/drivers/md/raid5.h linux-3.18.8/drivers/md/raid5.h
+--- linux-3.18.8.orig/drivers/md/raid5.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/md/raid5.h	2015-03-03 08:05:18.000000000 +0100
+@@ -457,6 +457,7 @@
+ 	int			recovery_disabled;
+ 	/* per cpu variables */
+ 	struct raid5_percpu {
++		spinlock_t	lock;	     /* Protection for -RT */
+ 		struct page	*spare_page; /* Used when checking P/Q in raid6 */
+ 		void		*scribble;   /* space for constructing buffer
+ 					      * lists and performing address
+diff -Nur linux-3.18.8.orig/drivers/misc/hwlat_detector.c linux-3.18.8/drivers/misc/hwlat_detector.c
+--- linux-3.18.8.orig/drivers/misc/hwlat_detector.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/drivers/misc/hwlat_detector.c	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,1240 @@
++/*
++ * hwlat_detector.c - A simple Hardware Latency detector.
++ *
++ * Use this module to detect large system latencies induced by the behavior of
++ * certain underlying system hardware or firmware, independent of Linux itself.
++ * The code was developed originally to detect the presence of SMIs on Intel
++ * and AMD systems, although there is no dependency upon x86 herein.
++ *
++ * The classical example usage of this module is in detecting the presence of
++ * SMIs or System Management Interrupts on Intel and AMD systems. An SMI is a
++ * somewhat special form of hardware interrupt spawned from earlier CPU debug
++ * modes in which the (BIOS/EFI/etc.) firmware arranges for the South Bridge
++ * LPC (or other device) to generate a special interrupt under certain
++ * circumstances, for example, upon expiration of a special SMI timer device,
++ * due to certain external thermal readings, on certain I/O address accesses,
++ * and other situations. An SMI hits a special CPU pin, triggers a special
++ * SMI mode (complete with special memory map), and the OS is unaware.
++ *
++ * Although certain hardware-inducing latencies are necessary (for example,
++ * a modern system often requires an SMI handler for correct thermal control
++ * and remote management) they can wreak havoc upon any OS-level performance
++ * guarantees toward low-latency, especially when the OS is not even made
++ * aware of the presence of these interrupts. For this reason, we need a
++ * somewhat brute force mechanism to detect these interrupts. In this case,
++ * we do it by hogging all of the CPU(s) for configurable timer intervals,
++ * sampling the built-in CPU timer, looking for discontiguous readings.
++ *
++ * WARNING: This implementation necessarily introduces latencies. Therefore,
++ *          you should NEVER use this module in a production environment
++ *          requiring any kind of low-latency performance guarantee(s).
++ *
++ * Copyright (C) 2008-2009 Jon Masters, Red Hat, Inc. <jcm@redhat.com>
++ *
++ * Includes useful feedback from Clark Williams <clark@redhat.com>
++ *
++ * This file is licensed under the terms of the GNU General Public
++ * License version 2. This program is licensed "as is" without any
++ * warranty of any kind, whether express or implied.
++ */
++
++#include <linux/module.h>
++#include <linux/init.h>
++#include <linux/ring_buffer.h>
++#include <linux/time.h>
++#include <linux/hrtimer.h>
++#include <linux/kthread.h>
++#include <linux/debugfs.h>
++#include <linux/seq_file.h>
++#include <linux/uaccess.h>
++#include <linux/version.h>
++#include <linux/delay.h>
++#include <linux/slab.h>
++#include <linux/trace_clock.h>
++
++#define BUF_SIZE_DEFAULT	262144UL		/* 8K*(sizeof(entry)) */
++#define BUF_FLAGS		(RB_FL_OVERWRITE)	/* no block on full */
++#define U64STR_SIZE		22			/* 20 digits max */
++
++#define VERSION			"1.0.0"
++#define BANNER			"hwlat_detector: "
++#define DRVNAME			"hwlat_detector"
++#define DEFAULT_SAMPLE_WINDOW	1000000			/* 1s */
++#define DEFAULT_SAMPLE_WIDTH	500000			/* 0.5s */
++#define DEFAULT_LAT_THRESHOLD	10			/* 10us */
++
++/* Module metadata */
++
++MODULE_LICENSE("GPL");
++MODULE_AUTHOR("Jon Masters <jcm@redhat.com>");
++MODULE_DESCRIPTION("A simple hardware latency detector");
++MODULE_VERSION(VERSION);
++
++/* Module parameters */
++
++static int debug;
++static int enabled;
++static int threshold;
++
++module_param(debug, int, 0);			/* enable debug */
++module_param(enabled, int, 0);			/* enable detector */
++module_param(threshold, int, 0);		/* latency threshold */
++
++/* Buffering and sampling */
++
++static struct ring_buffer *ring_buffer;		/* sample buffer */
++static DEFINE_MUTEX(ring_buffer_mutex);		/* lock changes */
++static unsigned long buf_size = BUF_SIZE_DEFAULT;
++static struct task_struct *kthread;		/* sampling thread */
++
++/* DebugFS filesystem entries */
++
++static struct dentry *debug_dir;		/* debugfs directory */
++static struct dentry *debug_max;		/* maximum TSC delta */
++static struct dentry *debug_count;		/* total detect count */
++static struct dentry *debug_sample_width;	/* sample width us */
++static struct dentry *debug_sample_window;	/* sample window us */
++static struct dentry *debug_sample;		/* raw samples us */
++static struct dentry *debug_threshold;		/* threshold us */
++static struct dentry *debug_enable;		/* enable/disable */
++
++/* Individual samples and global state */
++
++struct sample;					/* latency sample */
++struct data;					/* Global state */
++
++/* Sampling functions */
++static int __buffer_add_sample(struct sample *sample);
++static struct sample *buffer_get_sample(struct sample *sample);
++
++/* Threading and state */
++static int kthread_fn(void *unused);
++static int start_kthread(void);
++static int stop_kthread(void);
++static void __reset_stats(void);
++static int init_stats(void);
++
++/* Debugfs interface */
++static ssize_t simple_data_read(struct file *filp, char __user *ubuf,
++				size_t cnt, loff_t *ppos, const u64 *entry);
++static ssize_t simple_data_write(struct file *filp, const char __user *ubuf,
++				 size_t cnt, loff_t *ppos, u64 *entry);
++static int debug_sample_fopen(struct inode *inode, struct file *filp);
++static ssize_t debug_sample_fread(struct file *filp, char __user *ubuf,
++				  size_t cnt, loff_t *ppos);
++static int debug_sample_release(struct inode *inode, struct file *filp);
++static int debug_enable_fopen(struct inode *inode, struct file *filp);
++static ssize_t debug_enable_fread(struct file *filp, char __user *ubuf,
++				  size_t cnt, loff_t *ppos);
++static ssize_t debug_enable_fwrite(struct file *file,
++				   const char __user *user_buffer,
++				   size_t user_size, loff_t *offset);
++
++/* Initialization functions */
++static int init_debugfs(void);
++static void free_debugfs(void);
++static int detector_init(void);
++static void detector_exit(void);
++
++/* Individual latency samples are stored here when detected and packed into
++ * the ring_buffer circular buffer, where they are overwritten when
++ * more than buf_size/sizeof(sample) samples are received. */
++struct sample {
++	u64		seqnum;		/* unique sequence */
++	u64		duration;	/* ktime delta */
++	u64		outer_duration;	/* ktime delta (outer loop) */
++	struct timespec	timestamp;	/* wall time */
++	unsigned long   lost;
++};
++
++/* keep the global state somewhere. */
++static struct data {
++
++	struct mutex lock;		/* protect changes */
++
++	u64	count;			/* total since reset */
++	u64	max_sample;		/* max hardware latency */
++	u64	threshold;		/* sample threshold level */
++
++	u64	sample_window;		/* total sampling window (on+off) */
++	u64	sample_width;		/* active sampling portion of window */
++
++	atomic_t sample_open;		/* whether the sample file is open */
++
++	wait_queue_head_t wq;		/* waitqeue for new sample values */
++
++} data;
++
++/**
++ * __buffer_add_sample - add a new latency sample recording to the ring buffer
++ * @sample: The new latency sample value
++ *
++ * This receives a new latency sample and records it in a global ring buffer.
++ * No additional locking is used in this case.
++ */
++static int __buffer_add_sample(struct sample *sample)
++{
++	return ring_buffer_write(ring_buffer,
++				 sizeof(struct sample), sample);
++}
++
++/**
++ * buffer_get_sample - remove a hardware latency sample from the ring buffer
++ * @sample: Pre-allocated storage for the sample
++ *
++ * This retrieves a hardware latency sample from the global circular buffer
++ */
++static struct sample *buffer_get_sample(struct sample *sample)
++{
++	struct ring_buffer_event *e = NULL;
++	struct sample *s = NULL;
++	unsigned int cpu = 0;
++
++	if (!sample)
++		return NULL;
++
++	mutex_lock(&ring_buffer_mutex);
++	for_each_online_cpu(cpu) {
++		e = ring_buffer_consume(ring_buffer, cpu, NULL, &sample->lost);
++		if (e)
++			break;
++	}
++
++	if (e) {
++		s = ring_buffer_event_data(e);
++		memcpy(sample, s, sizeof(struct sample));
++	} else
++		sample = NULL;
++	mutex_unlock(&ring_buffer_mutex);
++
++	return sample;
++}
++
++#ifndef CONFIG_TRACING
++#define time_type	ktime_t
++#define time_get()	ktime_get()
++#define time_to_us(x)	ktime_to_us(x)
++#define time_sub(a, b)	ktime_sub(a, b)
++#define init_time(a, b)	(a).tv64 = b
++#define time_u64(a)	((a).tv64)
++#else
++#define time_type	u64
++#define time_get()	trace_clock_local()
++#define time_to_us(x)	div_u64(x, 1000)
++#define time_sub(a, b)	((a) - (b))
++#define init_time(a, b)	(a = b)
++#define time_u64(a)	a
++#endif
++/**
++ * get_sample - sample the CPU TSC and look for likely hardware latencies
++ *
++ * Used to repeatedly capture the CPU TSC (or similar), looking for potential
++ * hardware-induced latency. Called with interrupts disabled and with
++ * data.lock held.
++ */
++static int get_sample(void)
++{
++	time_type start, t1, t2, last_t2;
++	s64 diff, total = 0;
++	u64 sample = 0;
++	u64 outer_sample = 0;
++	int ret = -1;
++
++	init_time(last_t2, 0);
++	start = time_get(); /* start timestamp */
++
++	do {
++
++		t1 = time_get();	/* we'll look for a discontinuity */
++		t2 = time_get();
++
++		if (time_u64(last_t2)) {
++			/* Check the delta from outer loop (t2 to next t1) */
++			diff = time_to_us(time_sub(t1, last_t2));
++			/* This shouldn't happen */
++			if (diff < 0) {
++				pr_err(BANNER "time running backwards\n");
++				goto out;
++			}
++			if (diff > outer_sample)
++				outer_sample = diff;
++		}
++		last_t2 = t2;
++
++		total = time_to_us(time_sub(t2, start)); /* sample width */
++
++		/* This checks the inner loop (t1 to t2) */
++		diff = time_to_us(time_sub(t2, t1));     /* current diff */
++
++		/* This shouldn't happen */
++		if (diff < 0) {
++			pr_err(BANNER "time running backwards\n");
++			goto out;
++		}
++
++		if (diff > sample)
++			sample = diff; /* only want highest value */
++
++	} while (total <= data.sample_width);
++
++	ret = 0;
++
++	/* If we exceed the threshold value, we have found a hardware latency */
++	if (sample > data.threshold || outer_sample > data.threshold) {
++		struct sample s;
++
++		ret = 1;
++
++		data.count++;
++		s.seqnum = data.count;
++		s.duration = sample;
++		s.outer_duration = outer_sample;
++		s.timestamp = CURRENT_TIME;
++		__buffer_add_sample(&s);
++
++		/* Keep a running maximum ever recorded hardware latency */
++		if (sample > data.max_sample)
++			data.max_sample = sample;
++	}
++
++out:
++	return ret;
++}
++
++/*
++ * kthread_fn - The CPU time sampling/hardware latency detection kernel thread
++ * @unused: A required part of the kthread API.
++ *
++ * Used to periodically sample the CPU TSC via a call to get_sample. We
++ * disable interrupts, which does (intentionally) introduce latency since we
++ * need to ensure nothing else might be running (and thus pre-empting).
++ * Obviously this should never be used in production environments.
++ *
++ * Currently this runs on which ever CPU it was scheduled on, but most
++ * real-worald hardware latency situations occur across several CPUs,
++ * but we might later generalize this if we find there are any actualy
++ * systems with alternate SMI delivery or other hardware latencies.
++ */
++static int kthread_fn(void *unused)
++{
++	int ret;
++	u64 interval;
++
++	while (!kthread_should_stop()) {
++
++		mutex_lock(&data.lock);
++
++		local_irq_disable();
++		ret = get_sample();
++		local_irq_enable();
++
++		if (ret > 0)
++			wake_up(&data.wq); /* wake up reader(s) */
++
++		interval = data.sample_window - data.sample_width;
++		do_div(interval, USEC_PER_MSEC); /* modifies interval value */
++
++		mutex_unlock(&data.lock);
++
++		if (msleep_interruptible(interval))
++			break;
++	}
++
++	return 0;
++}
++
++/**
++ * start_kthread - Kick off the hardware latency sampling/detector kthread
++ *
++ * This starts a kernel thread that will sit and sample the CPU timestamp
++ * counter (TSC or similar) and look for potential hardware latencies.
++ */
++static int start_kthread(void)
++{
++	kthread = kthread_run(kthread_fn, NULL,
++					DRVNAME);
++	if (IS_ERR(kthread)) {
++		pr_err(BANNER "could not start sampling thread\n");
++		enabled = 0;
++		return -ENOMEM;
++	}
++
++	return 0;
++}
++
++/**
++ * stop_kthread - Inform the hardware latency samping/detector kthread to stop
++ *
++ * This kicks the running hardware latency sampling/detector kernel thread and
++ * tells it to stop sampling now. Use this on unload and at system shutdown.
++ */
++static int stop_kthread(void)
++{
++	int ret;
++
++	ret = kthread_stop(kthread);
++
++	return ret;
++}
++
++/**
++ * __reset_stats - Reset statistics for the hardware latency detector
++ *
++ * We use data to store various statistics and global state. We call this
++ * function in order to reset those when "enable" is toggled on or off, and
++ * also at initialization. Should be called with data.lock held.
++ */
++static void __reset_stats(void)
++{
++	data.count = 0;
++	data.max_sample = 0;
++	ring_buffer_reset(ring_buffer); /* flush out old sample entries */
++}
++
++/**
++ * init_stats - Setup global state statistics for the hardware latency detector
++ *
++ * We use data to store various statistics and global state. We also use
++ * a global ring buffer (ring_buffer) to keep raw samples of detected hardware
++ * induced system latencies. This function initializes these structures and
++ * allocates the global ring buffer also.
++ */
++static int init_stats(void)
++{
++	int ret = -ENOMEM;
++
++	mutex_init(&data.lock);
++	init_waitqueue_head(&data.wq);
++	atomic_set(&data.sample_open, 0);
++
++	ring_buffer = ring_buffer_alloc(buf_size, BUF_FLAGS);
++
++	if (WARN(!ring_buffer, KERN_ERR BANNER
++			       "failed to allocate ring buffer!\n"))
++		goto out;
++
++	__reset_stats();
++	data.threshold = threshold ?: DEFAULT_LAT_THRESHOLD; /* threshold us */
++	data.sample_window = DEFAULT_SAMPLE_WINDOW; /* window us */
++	data.sample_width = DEFAULT_SAMPLE_WIDTH;   /* width us */
++
++	ret = 0;
++
++out:
++	return ret;
++
++}
++
++/*
++ * simple_data_read - Wrapper read function for global state debugfs entries
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ * @entry: The entry to read from
++ *
++ * This function provides a generic read implementation for the global state
++ * "data" structure debugfs filesystem entries. It would be nice to use
++ * simple_attr_read directly, but we need to make sure that the data.lock
++ * is held during the actual read.
++ */
++static ssize_t simple_data_read(struct file *filp, char __user *ubuf,
++				size_t cnt, loff_t *ppos, const u64 *entry)
++{
++	char buf[U64STR_SIZE];
++	u64 val = 0;
++	int len = 0;
++
++	memset(buf, 0, sizeof(buf));
++
++	if (!entry)
++		return -EFAULT;
++
++	mutex_lock(&data.lock);
++	val = *entry;
++	mutex_unlock(&data.lock);
++
++	len = snprintf(buf, sizeof(buf), "%llu\n", (unsigned long long)val);
++
++	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
++
++}
++
++/*
++ * simple_data_write - Wrapper write function for global state debugfs entries
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to write value from
++ * @cnt: The maximum number of bytes to write
++ * @ppos: The current "file" position
++ * @entry: The entry to write to
++ *
++ * This function provides a generic write implementation for the global state
++ * "data" structure debugfs filesystem entries. It would be nice to use
++ * simple_attr_write directly, but we need to make sure that the data.lock
++ * is held during the actual write.
++ */
++static ssize_t simple_data_write(struct file *filp, const char __user *ubuf,
++				 size_t cnt, loff_t *ppos, u64 *entry)
++{
++	char buf[U64STR_SIZE];
++	int csize = min(cnt, sizeof(buf));
++	u64 val = 0;
++	int err = 0;
++
++	memset(buf, '\0', sizeof(buf));
++	if (copy_from_user(buf, ubuf, csize))
++		return -EFAULT;
++
++	buf[U64STR_SIZE-1] = '\0';			/* just in case */
++	err = kstrtoull(buf, 10, &val);
++	if (err)
++		return -EINVAL;
++
++	mutex_lock(&data.lock);
++	*entry = val;
++	mutex_unlock(&data.lock);
++
++	return csize;
++}
++
++/**
++ * debug_count_fopen - Open function for "count" debugfs entry
++ * @inode: The in-kernel inode representation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function provides an open implementation for the "count" debugfs
++ * interface to the hardware latency detector.
++ */
++static int debug_count_fopen(struct inode *inode, struct file *filp)
++{
++	return 0;
++}
++
++/**
++ * debug_count_fread - Read function for "count" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ *
++ * This function provides a read implementation for the "count" debugfs
++ * interface to the hardware latency detector. Can be used to read the
++ * number of latency readings exceeding the configured threshold since
++ * the detector was last reset (e.g. by writing a zero into "count").
++ */
++static ssize_t debug_count_fread(struct file *filp, char __user *ubuf,
++				     size_t cnt, loff_t *ppos)
++{
++	return simple_data_read(filp, ubuf, cnt, ppos, &data.count);
++}
++
++/**
++ * debug_count_fwrite - Write function for "count" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that contains the value to write
++ * @cnt: The maximum number of bytes to write to "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function provides a write implementation for the "count" debugfs
++ * interface to the hardware latency detector. Can be used to write a
++ * desired value, especially to zero the total count.
++ */
++static ssize_t  debug_count_fwrite(struct file *filp,
++				       const char __user *ubuf,
++				       size_t cnt,
++				       loff_t *ppos)
++{
++	return simple_data_write(filp, ubuf, cnt, ppos, &data.count);
++}
++
++/**
++ * debug_enable_fopen - Dummy open function for "enable" debugfs interface
++ * @inode: The in-kernel inode representation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function provides an open implementation for the "enable" debugfs
++ * interface to the hardware latency detector.
++ */
++static int debug_enable_fopen(struct inode *inode, struct file *filp)
++{
++	return 0;
++}
++
++/**
++ * debug_enable_fread - Read function for "enable" debugfs interface
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ *
++ * This function provides a read implementation for the "enable" debugfs
++ * interface to the hardware latency detector. Can be used to determine
++ * whether the detector is currently enabled ("0\n" or "1\n" returned).
++ */
++static ssize_t debug_enable_fread(struct file *filp, char __user *ubuf,
++				      size_t cnt, loff_t *ppos)
++{
++	char buf[4];
++
++	if ((cnt < sizeof(buf)) || (*ppos))
++		return 0;
++
++	buf[0] = enabled ? '1' : '0';
++	buf[1] = '\n';
++	buf[2] = '\0';
++	if (copy_to_user(ubuf, buf, strlen(buf)))
++		return -EFAULT;
++	return *ppos = strlen(buf);
++}
++
++/**
++ * debug_enable_fwrite - Write function for "enable" debugfs interface
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that contains the value to write
++ * @cnt: The maximum number of bytes to write to "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function provides a write implementation for the "enable" debugfs
++ * interface to the hardware latency detector. Can be used to enable or
++ * disable the detector, which will have the side-effect of possibly
++ * also resetting the global stats and kicking off the measuring
++ * kthread (on an enable) or the converse (upon a disable).
++ */
++static ssize_t  debug_enable_fwrite(struct file *filp,
++					const char __user *ubuf,
++					size_t cnt,
++					loff_t *ppos)
++{
++	char buf[4];
++	int csize = min(cnt, sizeof(buf));
++	long val = 0;
++	int err = 0;
++
++	memset(buf, '\0', sizeof(buf));
++	if (copy_from_user(buf, ubuf, csize))
++		return -EFAULT;
++
++	buf[sizeof(buf)-1] = '\0';			/* just in case */
++	err = kstrtoul(buf, 10, &val);
++	if (0 != err)
++		return -EINVAL;
++
++	if (val) {
++		if (enabled)
++			goto unlock;
++		enabled = 1;
++		__reset_stats();
++		if (start_kthread())
++			return -EFAULT;
++	} else {
++		if (!enabled)
++			goto unlock;
++		enabled = 0;
++		err = stop_kthread();
++		if (err) {
++			pr_err(BANNER "cannot stop kthread\n");
++			return -EFAULT;
++		}
++		wake_up(&data.wq);		/* reader(s) should return */
++	}
++unlock:
++	return csize;
++}
++
++/**
++ * debug_max_fopen - Open function for "max" debugfs entry
++ * @inode: The in-kernel inode representation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function provides an open implementation for the "max" debugfs
++ * interface to the hardware latency detector.
++ */
++static int debug_max_fopen(struct inode *inode, struct file *filp)
++{
++	return 0;
++}
++
++/**
++ * debug_max_fread - Read function for "max" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ *
++ * This function provides a read implementation for the "max" debugfs
++ * interface to the hardware latency detector. Can be used to determine
++ * the maximum latency value observed since it was last reset.
++ */
++static ssize_t debug_max_fread(struct file *filp, char __user *ubuf,
++				   size_t cnt, loff_t *ppos)
++{
++	return simple_data_read(filp, ubuf, cnt, ppos, &data.max_sample);
++}
++
++/**
++ * debug_max_fwrite - Write function for "max" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that contains the value to write
++ * @cnt: The maximum number of bytes to write to "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function provides a write implementation for the "max" debugfs
++ * interface to the hardware latency detector. Can be used to reset the
++ * maximum or set it to some other desired value - if, then, subsequent
++ * measurements exceed this value, the maximum will be updated.
++ */
++static ssize_t  debug_max_fwrite(struct file *filp,
++				     const char __user *ubuf,
++				     size_t cnt,
++				     loff_t *ppos)
++{
++	return simple_data_write(filp, ubuf, cnt, ppos, &data.max_sample);
++}
++
++
++/**
++ * debug_sample_fopen - An open function for "sample" debugfs interface
++ * @inode: The in-kernel inode representation of this debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function handles opening the "sample" file within the hardware
++ * latency detector debugfs directory interface. This file is used to read
++ * raw samples from the global ring_buffer and allows the user to see a
++ * running latency history. Can be opened blocking or non-blocking,
++ * affecting whether it behaves as a buffer read pipe, or does not.
++ * Implements simple locking to prevent multiple simultaneous use.
++ */
++static int debug_sample_fopen(struct inode *inode, struct file *filp)
++{
++	if (!atomic_add_unless(&data.sample_open, 1, 1))
++		return -EBUSY;
++	else
++		return 0;
++}
++
++/**
++ * debug_sample_fread - A read function for "sample" debugfs interface
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that will contain the samples read
++ * @cnt: The maximum bytes to read from the debugfs "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function handles reading from the "sample" file within the hardware
++ * latency detector debugfs directory interface. This file is used to read
++ * raw samples from the global ring_buffer and allows the user to see a
++ * running latency history. By default this will block pending a new
++ * value written into the sample buffer, unless there are already a
++ * number of value(s) waiting in the buffer, or the sample file was
++ * previously opened in a non-blocking mode of operation.
++ */
++static ssize_t debug_sample_fread(struct file *filp, char __user *ubuf,
++					size_t cnt, loff_t *ppos)
++{
++	int len = 0;
++	char buf[64];
++	struct sample *sample = NULL;
++
++	if (!enabled)
++		return 0;
++
++	sample = kzalloc(sizeof(struct sample), GFP_KERNEL);
++	if (!sample)
++		return -ENOMEM;
++
++	while (!buffer_get_sample(sample)) {
++
++		DEFINE_WAIT(wait);
++
++		if (filp->f_flags & O_NONBLOCK) {
++			len = -EAGAIN;
++			goto out;
++		}
++
++		prepare_to_wait(&data.wq, &wait, TASK_INTERRUPTIBLE);
++		schedule();
++		finish_wait(&data.wq, &wait);
++
++		if (signal_pending(current)) {
++			len = -EINTR;
++			goto out;
++		}
++
++		if (!enabled) {			/* enable was toggled */
++			len = 0;
++			goto out;
++		}
++	}
++
++	len = snprintf(buf, sizeof(buf), "%010lu.%010lu\t%llu\t%llu\n",
++		       sample->timestamp.tv_sec,
++		       sample->timestamp.tv_nsec,
++		       sample->duration,
++		       sample->outer_duration);
++
++
++	/* handling partial reads is more trouble than it's worth */
++	if (len > cnt)
++		goto out;
++
++	if (copy_to_user(ubuf, buf, len))
++		len = -EFAULT;
++
++out:
++	kfree(sample);
++	return len;
++}
++
++/**
++ * debug_sample_release - Release function for "sample" debugfs interface
++ * @inode: The in-kernel inode represenation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function completes the close of the debugfs interface "sample" file.
++ * Frees the sample_open "lock" so that other users may open the interface.
++ */
++static int debug_sample_release(struct inode *inode, struct file *filp)
++{
++	atomic_dec(&data.sample_open);
++
++	return 0;
++}
++
++/**
++ * debug_threshold_fopen - Open function for "threshold" debugfs entry
++ * @inode: The in-kernel inode representation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function provides an open implementation for the "threshold" debugfs
++ * interface to the hardware latency detector.
++ */
++static int debug_threshold_fopen(struct inode *inode, struct file *filp)
++{
++	return 0;
++}
++
++/**
++ * debug_threshold_fread - Read function for "threshold" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ *
++ * This function provides a read implementation for the "threshold" debugfs
++ * interface to the hardware latency detector. It can be used to determine
++ * the current threshold level at which a latency will be recorded in the
++ * global ring buffer, typically on the order of 10us.
++ */
++static ssize_t debug_threshold_fread(struct file *filp, char __user *ubuf,
++					 size_t cnt, loff_t *ppos)
++{
++	return simple_data_read(filp, ubuf, cnt, ppos, &data.threshold);
++}
++
++/**
++ * debug_threshold_fwrite - Write function for "threshold" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that contains the value to write
++ * @cnt: The maximum number of bytes to write to "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function provides a write implementation for the "threshold" debugfs
++ * interface to the hardware latency detector. It can be used to configure
++ * the threshold level at which any subsequently detected latencies will
++ * be recorded into the global ring buffer.
++ */
++static ssize_t  debug_threshold_fwrite(struct file *filp,
++					const char __user *ubuf,
++					size_t cnt,
++					loff_t *ppos)
++{
++	int ret;
++
++	ret = simple_data_write(filp, ubuf, cnt, ppos, &data.threshold);
++
++	if (enabled)
++		wake_up_process(kthread);
++
++	return ret;
++}
++
++/**
++ * debug_width_fopen - Open function for "width" debugfs entry
++ * @inode: The in-kernel inode representation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function provides an open implementation for the "width" debugfs
++ * interface to the hardware latency detector.
++ */
++static int debug_width_fopen(struct inode *inode, struct file *filp)
++{
++	return 0;
++}
++
++/**
++ * debug_width_fread - Read function for "width" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ *
++ * This function provides a read implementation for the "width" debugfs
++ * interface to the hardware latency detector. It can be used to determine
++ * for how many us of the total window us we will actively sample for any
++ * hardware-induced latecy periods. Obviously, it is not possible to
++ * sample constantly and have the system respond to a sample reader, or,
++ * worse, without having the system appear to have gone out to lunch.
++ */
++static ssize_t debug_width_fread(struct file *filp, char __user *ubuf,
++				     size_t cnt, loff_t *ppos)
++{
++	return simple_data_read(filp, ubuf, cnt, ppos, &data.sample_width);
++}
++
++/**
++ * debug_width_fwrite - Write function for "width" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that contains the value to write
++ * @cnt: The maximum number of bytes to write to "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function provides a write implementation for the "width" debugfs
++ * interface to the hardware latency detector. It can be used to configure
++ * for how many us of the total window us we will actively sample for any
++ * hardware-induced latency periods. Obviously, it is not possible to
++ * sample constantly and have the system respond to a sample reader, or,
++ * worse, without having the system appear to have gone out to lunch. It
++ * is enforced that width is less that the total window size.
++ */
++static ssize_t  debug_width_fwrite(struct file *filp,
++				       const char __user *ubuf,
++				       size_t cnt,
++				       loff_t *ppos)
++{
++	char buf[U64STR_SIZE];
++	int csize = min(cnt, sizeof(buf));
++	u64 val = 0;
++	int err = 0;
++
++	memset(buf, '\0', sizeof(buf));
++	if (copy_from_user(buf, ubuf, csize))
++		return -EFAULT;
++
++	buf[U64STR_SIZE-1] = '\0';			/* just in case */
++	err = kstrtoull(buf, 10, &val);
++	if (0 != err)
++		return -EINVAL;
++
++	mutex_lock(&data.lock);
++	if (val < data.sample_window)
++		data.sample_width = val;
++	else {
++		mutex_unlock(&data.lock);
++		return -EINVAL;
++	}
++	mutex_unlock(&data.lock);
++
++	if (enabled)
++		wake_up_process(kthread);
++
++	return csize;
++}
++
++/**
++ * debug_window_fopen - Open function for "window" debugfs entry
++ * @inode: The in-kernel inode representation of the debugfs "file"
++ * @filp: The active open file structure for the debugfs "file"
++ *
++ * This function provides an open implementation for the "window" debugfs
++ * interface to the hardware latency detector. The window is the total time
++ * in us that will be considered one sample period. Conceptually, windows
++ * occur back-to-back and contain a sample width period during which
++ * actual sampling occurs.
++ */
++static int debug_window_fopen(struct inode *inode, struct file *filp)
++{
++	return 0;
++}
++
++/**
++ * debug_window_fread - Read function for "window" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The userspace provided buffer to read value into
++ * @cnt: The maximum number of bytes to read
++ * @ppos: The current "file" position
++ *
++ * This function provides a read implementation for the "window" debugfs
++ * interface to the hardware latency detector. The window is the total time
++ * in us that will be considered one sample period. Conceptually, windows
++ * occur back-to-back and contain a sample width period during which
++ * actual sampling occurs. Can be used to read the total window size.
++ */
++static ssize_t debug_window_fread(struct file *filp, char __user *ubuf,
++				      size_t cnt, loff_t *ppos)
++{
++	return simple_data_read(filp, ubuf, cnt, ppos, &data.sample_window);
++}
++
++/**
++ * debug_window_fwrite - Write function for "window" debugfs entry
++ * @filp: The active open file structure for the debugfs "file"
++ * @ubuf: The user buffer that contains the value to write
++ * @cnt: The maximum number of bytes to write to "file"
++ * @ppos: The current position in the debugfs "file"
++ *
++ * This function provides a write implementation for the "window" debufds
++ * interface to the hardware latency detetector. The window is the total time
++ * in us that will be considered one sample period. Conceptually, windows
++ * occur back-to-back and contain a sample width period during which
++ * actual sampling occurs. Can be used to write a new total window size. It
++ * is enfoced that any value written must be greater than the sample width
++ * size, or an error results.
++ */
++static ssize_t  debug_window_fwrite(struct file *filp,
++					const char __user *ubuf,
++					size_t cnt,
++					loff_t *ppos)
++{
++	char buf[U64STR_SIZE];
++	int csize = min(cnt, sizeof(buf));
++	u64 val = 0;
++	int err = 0;
++
++	memset(buf, '\0', sizeof(buf));
++	if (copy_from_user(buf, ubuf, csize))
++		return -EFAULT;
++
++	buf[U64STR_SIZE-1] = '\0';			/* just in case */
++	err = kstrtoull(buf, 10, &val);
++	if (0 != err)
++		return -EINVAL;
++
++	mutex_lock(&data.lock);
++	if (data.sample_width < val)
++		data.sample_window = val;
++	else {
++		mutex_unlock(&data.lock);
++		return -EINVAL;
++	}
++	mutex_unlock(&data.lock);
++
++	return csize;
++}
++
++/*
++ * Function pointers for the "count" debugfs file operations
++ */
++static const struct file_operations count_fops = {
++	.open		= debug_count_fopen,
++	.read		= debug_count_fread,
++	.write		= debug_count_fwrite,
++	.owner		= THIS_MODULE,
++};
++
++/*
++ * Function pointers for the "enable" debugfs file operations
++ */
++static const struct file_operations enable_fops = {
++	.open		= debug_enable_fopen,
++	.read		= debug_enable_fread,
++	.write		= debug_enable_fwrite,
++	.owner		= THIS_MODULE,
++};
++
++/*
++ * Function pointers for the "max" debugfs file operations
++ */
++static const struct file_operations max_fops = {
++	.open		= debug_max_fopen,
++	.read		= debug_max_fread,
++	.write		= debug_max_fwrite,
++	.owner		= THIS_MODULE,
++};
++
++/*
++ * Function pointers for the "sample" debugfs file operations
++ */
++static const struct file_operations sample_fops = {
++	.open		= debug_sample_fopen,
++	.read		= debug_sample_fread,
++	.release	= debug_sample_release,
++	.owner		= THIS_MODULE,
++};
++
++/*
++ * Function pointers for the "threshold" debugfs file operations
++ */
++static const struct file_operations threshold_fops = {
++	.open		= debug_threshold_fopen,
++	.read		= debug_threshold_fread,
++	.write		= debug_threshold_fwrite,
++	.owner		= THIS_MODULE,
++};
++
++/*
++ * Function pointers for the "width" debugfs file operations
++ */
++static const struct file_operations width_fops = {
++	.open		= debug_width_fopen,
++	.read		= debug_width_fread,
++	.write		= debug_width_fwrite,
++	.owner		= THIS_MODULE,
++};
++
++/*
++ * Function pointers for the "window" debugfs file operations
++ */
++static const struct file_operations window_fops = {
++	.open		= debug_window_fopen,
++	.read		= debug_window_fread,
++	.write		= debug_window_fwrite,
++	.owner		= THIS_MODULE,
++};
++
++/**
++ * init_debugfs - A function to initialize the debugfs interface files
++ *
++ * This function creates entries in debugfs for "hwlat_detector", including
++ * files to read values from the detector, current samples, and the
++ * maximum sample that has been captured since the hardware latency
++ * dectector was started.
++ */
++static int init_debugfs(void)
++{
++	int ret = -ENOMEM;
++
++	debug_dir = debugfs_create_dir(DRVNAME, NULL);
++	if (!debug_dir)
++		goto err_debug_dir;
++
++	debug_sample = debugfs_create_file("sample", 0444,
++					       debug_dir, NULL,
++					       &sample_fops);
++	if (!debug_sample)
++		goto err_sample;
++
++	debug_count = debugfs_create_file("count", 0444,
++					      debug_dir, NULL,
++					      &count_fops);
++	if (!debug_count)
++		goto err_count;
++
++	debug_max = debugfs_create_file("max", 0444,
++					    debug_dir, NULL,
++					    &max_fops);
++	if (!debug_max)
++		goto err_max;
++
++	debug_sample_window = debugfs_create_file("window", 0644,
++						      debug_dir, NULL,
++						      &window_fops);
++	if (!debug_sample_window)
++		goto err_window;
++
++	debug_sample_width = debugfs_create_file("width", 0644,
++						     debug_dir, NULL,
++						     &width_fops);
++	if (!debug_sample_width)
++		goto err_width;
++
++	debug_threshold = debugfs_create_file("threshold", 0644,
++						  debug_dir, NULL,
++						  &threshold_fops);
++	if (!debug_threshold)
++		goto err_threshold;
++
++	debug_enable = debugfs_create_file("enable", 0644,
++					       debug_dir, &enabled,
++					       &enable_fops);
++	if (!debug_enable)
++		goto err_enable;
++
++	else {
++		ret = 0;
++		goto out;
++	}
++
++err_enable:
++	debugfs_remove(debug_threshold);
++err_threshold:
++	debugfs_remove(debug_sample_width);
++err_width:
++	debugfs_remove(debug_sample_window);
++err_window:
++	debugfs_remove(debug_max);
++err_max:
++	debugfs_remove(debug_count);
++err_count:
++	debugfs_remove(debug_sample);
++err_sample:
++	debugfs_remove(debug_dir);
++err_debug_dir:
++out:
++	return ret;
++}
++
++/**
++ * free_debugfs - A function to cleanup the debugfs file interface
++ */
++static void free_debugfs(void)
++{
++	/* could also use a debugfs_remove_recursive */
++	debugfs_remove(debug_enable);
++	debugfs_remove(debug_threshold);
++	debugfs_remove(debug_sample_width);
++	debugfs_remove(debug_sample_window);
++	debugfs_remove(debug_max);
++	debugfs_remove(debug_count);
++	debugfs_remove(debug_sample);
++	debugfs_remove(debug_dir);
++}
++
++/**
++ * detector_init - Standard module initialization code
++ */
++static int detector_init(void)
++{
++	int ret = -ENOMEM;
++
++	pr_info(BANNER "version %s\n", VERSION);
++
++	ret = init_stats();
++	if (0 != ret)
++		goto out;
++
++	ret = init_debugfs();
++	if (0 != ret)
++		goto err_stats;
++
++	if (enabled)
++		ret = start_kthread();
++
++	goto out;
++
++err_stats:
++	ring_buffer_free(ring_buffer);
++out:
++	return ret;
++
++}
++
++/**
++ * detector_exit - Standard module cleanup code
++ */
++static void detector_exit(void)
++{
++	int err;
++
++	if (enabled) {
++		enabled = 0;
++		err = stop_kthread();
++		if (err)
++			pr_err(BANNER "cannot stop kthread\n");
++	}
++
++	free_debugfs();
++	ring_buffer_free(ring_buffer);	/* free up the ring buffer */
++
++}
++
++module_init(detector_init);
++module_exit(detector_exit);
+diff -Nur linux-3.18.8.orig/drivers/misc/Kconfig linux-3.18.8/drivers/misc/Kconfig
+--- linux-3.18.8.orig/drivers/misc/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/misc/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -54,6 +54,7 @@
+ config ATMEL_TCLIB
+ 	bool "Atmel AT32/AT91 Timer/Counter Library"
+ 	depends on (AVR32 || ARCH_AT91)
++	default y if PREEMPT_RT_FULL
+ 	help
+ 	  Select this if you want a library to allocate the Timer/Counter
+ 	  blocks found on many Atmel processors.  This facilitates using
+@@ -69,8 +70,7 @@
+ 	  are combined to make a single 32-bit timer.
+ 
+ 	  When GENERIC_CLOCKEVENTS is defined, the third timer channel
+-	  may be used as a clock event device supporting oneshot mode
+-	  (delays of up to two seconds) based on the 32 KiHz clock.
++	  may be used as a clock event device supporting oneshot mode.
+ 
+ config ATMEL_TCB_CLKSRC_BLOCK
+ 	int
+@@ -84,6 +84,15 @@
+ 	  TC can be used for other purposes, such as PWM generation and
+ 	  interval timing.
+ 
++config ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
++	bool "TC Block use 32 KiHz clock"
++	depends on ATMEL_TCB_CLKSRC
++	default y if !PREEMPT_RT_FULL
++	help
++	  Select this to use 32 KiHz base clock rate as TC block clock
++	  source for clock events.
++
++
+ config DUMMY_IRQ
+ 	tristate "Dummy IRQ handler"
+ 	default n
+@@ -113,6 +122,35 @@
+ 	  for information on the specific driver level and support statement
+ 	  for your IBM server.
+ 
++config HWLAT_DETECTOR
++	tristate "Testing module to detect hardware-induced latencies"
++	depends on DEBUG_FS
++	depends on RING_BUFFER
++	default m
++	---help---
++	  A simple hardware latency detector. Use this module to detect
++	  large latencies introduced by the behavior of the underlying
++	  system firmware external to Linux. We do this using periodic
++	  use of stop_machine to grab all available CPUs and measure
++	  for unexplainable gaps in the CPU timestamp counter(s). By
++	  default, the module is not enabled until the "enable" file
++	  within the "hwlat_detector" debugfs directory is toggled.
++
++	  This module is often used to detect SMI (System Management
++	  Interrupts) on x86 systems, though is not x86 specific. To
++	  this end, we default to using a sample window of 1 second,
++	  during which we will sample for 0.5 seconds. If an SMI or
++	  similar event occurs during that time, it is recorded
++	  into an 8K samples global ring buffer until retreived.
++
++	  WARNING: This software should never be enabled (it can be built
++	  but should not be turned on after it is loaded) in a production
++	  environment where high latencies are a concern since the
++	  sampling mechanism actually introduces latencies for
++	  regular tasks while the CPU(s) are being held.
++
++	  If unsure, say N
++
+ config PHANTOM
+ 	tristate "Sensable PHANToM (PCI)"
+ 	depends on PCI
+diff -Nur linux-3.18.8.orig/drivers/misc/Makefile linux-3.18.8/drivers/misc/Makefile
+--- linux-3.18.8.orig/drivers/misc/Makefile	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/misc/Makefile	2015-03-03 08:05:18.000000000 +0100
+@@ -38,6 +38,7 @@
+ obj-$(CONFIG_HMC6352)		+= hmc6352.o
+ obj-y				+= eeprom/
+ obj-y				+= cb710/
++obj-$(CONFIG_HWLAT_DETECTOR)	+= hwlat_detector.o
+ obj-$(CONFIG_SPEAR13XX_PCIE_GADGET)	+= spear13xx_pcie_gadget.o
+ obj-$(CONFIG_VMWARE_BALLOON)	+= vmw_balloon.o
+ obj-$(CONFIG_ARM_CHARLCD)	+= arm-charlcd.o
+diff -Nur linux-3.18.8.orig/drivers/mmc/host/mmci.c linux-3.18.8/drivers/mmc/host/mmci.c
+--- linux-3.18.8.orig/drivers/mmc/host/mmci.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/mmc/host/mmci.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1153,15 +1153,12 @@
+ 	struct sg_mapping_iter *sg_miter = &host->sg_miter;
+ 	struct variant_data *variant = host->variant;
+ 	void __iomem *base = host->base;
+-	unsigned long flags;
+ 	u32 status;
+ 
+ 	status = readl(base + MMCISTATUS);
+ 
+ 	dev_dbg(mmc_dev(host->mmc), "irq1 (pio) %08x\n", status);
+ 
+-	local_irq_save(flags);
+-
+ 	do {
+ 		unsigned int remain, len;
+ 		char *buffer;
+@@ -1201,8 +1198,6 @@
+ 
+ 	sg_miter_stop(sg_miter);
+ 
+-	local_irq_restore(flags);
+-
+ 	/*
+ 	 * If we have less than the fifo 'half-full' threshold to transfer,
+ 	 * trigger a PIO interrupt as soon as any data is available.
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/3com/3c59x.c linux-3.18.8/drivers/net/ethernet/3com/3c59x.c
+--- linux-3.18.8.orig/drivers/net/ethernet/3com/3c59x.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/3com/3c59x.c	2015-03-03 08:05:18.000000000 +0100
+@@ -842,9 +842,9 @@
+ {
+ 	struct vortex_private *vp = netdev_priv(dev);
+ 	unsigned long flags;
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	(vp->full_bus_master_rx ? boomerang_interrupt:vortex_interrupt)(dev->irq,dev);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ }
+ #endif
+ 
+@@ -1916,12 +1916,12 @@
+ 			 * Block interrupts because vortex_interrupt does a bare spin_lock()
+ 			 */
+ 			unsigned long flags;
+-			local_irq_save(flags);
++			local_irq_save_nort(flags);
+ 			if (vp->full_bus_master_tx)
+ 				boomerang_interrupt(dev->irq, dev);
+ 			else
+ 				vortex_interrupt(dev->irq, dev);
+-			local_irq_restore(flags);
++			local_irq_restore_nort(flags);
+ 		}
+ 	}
+ 
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/atheros/atl1c/atl1c_main.c linux-3.18.8/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+--- linux-3.18.8.orig/drivers/net/ethernet/atheros/atl1c/atl1c_main.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/atheros/atl1c/atl1c_main.c	2015-03-03 08:05:18.000000000 +0100
+@@ -2213,11 +2213,7 @@
+ 	}
+ 
+ 	tpd_req = atl1c_cal_tpd_req(skb);
+-	if (!spin_trylock_irqsave(&adapter->tx_lock, flags)) {
+-		if (netif_msg_pktdata(adapter))
+-			dev_info(&adapter->pdev->dev, "tx locked\n");
+-		return NETDEV_TX_LOCKED;
+-	}
++	spin_lock_irqsave(&adapter->tx_lock, flags);
+ 
+ 	if (atl1c_tpd_avail(adapter, type) < tpd_req) {
+ 		/* no enough descriptor, just stop queue */
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/atheros/atl1e/atl1e_main.c linux-3.18.8/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
+--- linux-3.18.8.orig/drivers/net/ethernet/atheros/atl1e/atl1e_main.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/atheros/atl1e/atl1e_main.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1880,8 +1880,7 @@
+ 		return NETDEV_TX_OK;
+ 	}
+ 	tpd_req = atl1e_cal_tdp_req(skb);
+-	if (!spin_trylock_irqsave(&adapter->tx_lock, flags))
+-		return NETDEV_TX_LOCKED;
++	spin_lock_irqsave(&adapter->tx_lock, flags);
+ 
+ 	if (atl1e_tpd_avail(adapter) < tpd_req) {
+ 		/* no enough descriptor, just stop queue */
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/chelsio/cxgb/sge.c linux-3.18.8/drivers/net/ethernet/chelsio/cxgb/sge.c
+--- linux-3.18.8.orig/drivers/net/ethernet/chelsio/cxgb/sge.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/chelsio/cxgb/sge.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1663,8 +1663,7 @@
+ 	struct cmdQ *q = &sge->cmdQ[qid];
+ 	unsigned int credits, pidx, genbit, count, use_sched_skb = 0;
+ 
+-	if (!spin_trylock(&q->lock))
+-		return NETDEV_TX_LOCKED;
++	spin_lock(&q->lock);
+ 
+ 	reclaim_completed_tx(sge, q);
+ 
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/freescale/gianfar.c linux-3.18.8/drivers/net/ethernet/freescale/gianfar.c
+--- linux-3.18.8.orig/drivers/net/ethernet/freescale/gianfar.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/freescale/gianfar.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1483,7 +1483,7 @@
+ 
+ 	if (netif_running(ndev)) {
+ 
+-		local_irq_save(flags);
++		local_irq_save_nort(flags);
+ 		lock_tx_qs(priv);
+ 
+ 		gfar_halt_nodisable(priv);
+@@ -1499,7 +1499,7 @@
+ 		gfar_write(&regs->maccfg1, tempval);
+ 
+ 		unlock_tx_qs(priv);
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 
+ 		disable_napi(priv);
+ 
+@@ -1541,7 +1541,7 @@
+ 	/* Disable Magic Packet mode, in case something
+ 	 * else woke us up.
+ 	 */
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	lock_tx_qs(priv);
+ 
+ 	tempval = gfar_read(&regs->maccfg2);
+@@ -1551,7 +1551,7 @@
+ 	gfar_start(priv);
+ 
+ 	unlock_tx_qs(priv);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	netif_device_attach(ndev);
+ 
+@@ -3307,14 +3307,14 @@
+ 			dev->stats.tx_dropped++;
+ 			atomic64_inc(&priv->extra_stats.tx_underrun);
+ 
+-			local_irq_save(flags);
++			local_irq_save_nort(flags);
+ 			lock_tx_qs(priv);
+ 
+ 			/* Reactivate the Tx Queues */
+ 			gfar_write(&regs->tstat, gfargrp->tstat);
+ 
+ 			unlock_tx_qs(priv);
+-			local_irq_restore(flags);
++			local_irq_restore_nort(flags);
+ 		}
+ 		netif_dbg(priv, tx_err, dev, "Transmit Error\n");
+ 	}
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/neterion/s2io.c linux-3.18.8/drivers/net/ethernet/neterion/s2io.c
+--- linux-3.18.8.orig/drivers/net/ethernet/neterion/s2io.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/neterion/s2io.c	2015-03-03 08:05:18.000000000 +0100
+@@ -4084,12 +4084,7 @@
+ 			[skb->priority & (MAX_TX_FIFOS - 1)];
+ 	fifo = &mac_control->fifos[queue];
+ 
+-	if (do_spin_lock)
+-		spin_lock_irqsave(&fifo->tx_lock, flags);
+-	else {
+-		if (unlikely(!spin_trylock_irqsave(&fifo->tx_lock, flags)))
+-			return NETDEV_TX_LOCKED;
+-	}
++	spin_lock_irqsave(&fifo->tx_lock, flags);
+ 
+ 	if (sp->config.multiq) {
+ 		if (__netif_subqueue_stopped(dev, fifo->fifo_no)) {
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c linux-3.18.8/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
+--- linux-3.18.8.orig/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c	2015-03-03 08:05:18.000000000 +0100
+@@ -2137,10 +2137,8 @@
+ 	struct pch_gbe_tx_ring *tx_ring = adapter->tx_ring;
+ 	unsigned long flags;
+ 
+-	if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags)) {
+-		/* Collision - tell upper layer to requeue */
+-		return NETDEV_TX_LOCKED;
+-	}
++	spin_lock_irqsave(&tx_ring->tx_lock, flags);
++
+ 	if (unlikely(!PCH_GBE_DESC_UNUSED(tx_ring))) {
+ 		netif_stop_queue(netdev);
+ 		spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/realtek/8139too.c linux-3.18.8/drivers/net/ethernet/realtek/8139too.c
+--- linux-3.18.8.orig/drivers/net/ethernet/realtek/8139too.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/realtek/8139too.c	2015-03-03 08:05:18.000000000 +0100
+@@ -2215,7 +2215,7 @@
+ 	struct rtl8139_private *tp = netdev_priv(dev);
+ 	const int irq = tp->pci_dev->irq;
+ 
+-	disable_irq(irq);
++	disable_irq_nosync(irq);
+ 	rtl8139_interrupt(irq, dev);
+ 	enable_irq(irq);
+ }
+diff -Nur linux-3.18.8.orig/drivers/net/ethernet/tehuti/tehuti.c linux-3.18.8/drivers/net/ethernet/tehuti/tehuti.c
+--- linux-3.18.8.orig/drivers/net/ethernet/tehuti/tehuti.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/ethernet/tehuti/tehuti.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1629,13 +1629,8 @@
+ 	unsigned long flags;
+ 
+ 	ENTER;
+-	local_irq_save(flags);
+-	if (!spin_trylock(&priv->tx_lock)) {
+-		local_irq_restore(flags);
+-		DBG("%s[%s]: TX locked, returning NETDEV_TX_LOCKED\n",
+-		    BDX_DRV_NAME, ndev->name);
+-		return NETDEV_TX_LOCKED;
+-	}
++
++	spin_lock_irqsave(&priv->tx_lock, flags);
+ 
+ 	/* build tx descriptor */
+ 	BDX_ASSERT(f->m.wptr >= f->m.memsz);	/* started with valid wptr */
+diff -Nur linux-3.18.8.orig/drivers/net/rionet.c linux-3.18.8/drivers/net/rionet.c
+--- linux-3.18.8.orig/drivers/net/rionet.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/rionet.c	2015-03-03 08:05:18.000000000 +0100
+@@ -174,11 +174,7 @@
+ 	unsigned long flags;
+ 	int add_num = 1;
+ 
+-	local_irq_save(flags);
+-	if (!spin_trylock(&rnet->tx_lock)) {
+-		local_irq_restore(flags);
+-		return NETDEV_TX_LOCKED;
+-	}
++	spin_lock_irqsave(&rnet->tx_lock, flags);
+ 
+ 	if (is_multicast_ether_addr(eth->h_dest))
+ 		add_num = nets[rnet->mport->id].nact;
+diff -Nur linux-3.18.8.orig/drivers/net/wireless/orinoco/orinoco_usb.c linux-3.18.8/drivers/net/wireless/orinoco/orinoco_usb.c
+--- linux-3.18.8.orig/drivers/net/wireless/orinoco/orinoco_usb.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/net/wireless/orinoco/orinoco_usb.c	2015-03-03 08:05:18.000000000 +0100
+@@ -699,7 +699,7 @@
+ 			while (!ctx->done.done && msecs--)
+ 				udelay(1000);
+ 		} else {
+-			wait_event_interruptible(ctx->done.wait,
++			swait_event_interruptible(ctx->done.wait,
+ 						 ctx->done.done);
+ 		}
+ 		break;
+diff -Nur linux-3.18.8.orig/drivers/pci/access.c linux-3.18.8/drivers/pci/access.c
+--- linux-3.18.8.orig/drivers/pci/access.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/pci/access.c	2015-03-03 08:05:18.000000000 +0100
+@@ -434,7 +434,7 @@
+ 	WARN_ON(!dev->block_cfg_access);
+ 
+ 	dev->block_cfg_access = 0;
+-	wake_up_all(&pci_cfg_wait);
++	wake_up_all_locked(&pci_cfg_wait);
+ 	raw_spin_unlock_irqrestore(&pci_lock, flags);
+ }
+ EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);
+diff -Nur linux-3.18.8.orig/drivers/scsi/fcoe/fcoe.c linux-3.18.8/drivers/scsi/fcoe/fcoe.c
+--- linux-3.18.8.orig/drivers/scsi/fcoe/fcoe.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/scsi/fcoe/fcoe.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1286,7 +1286,7 @@
+ 	struct sk_buff *skb;
+ #ifdef CONFIG_SMP
+ 	struct fcoe_percpu_s *p0;
+-	unsigned targ_cpu = get_cpu();
++	unsigned targ_cpu = get_cpu_light();
+ #endif /* CONFIG_SMP */
+ 
+ 	FCOE_DBG("Destroying receive thread for CPU %d\n", cpu);
+@@ -1342,7 +1342,7 @@
+ 			kfree_skb(skb);
+ 		spin_unlock_bh(&p->fcoe_rx_list.lock);
+ 	}
+-	put_cpu();
++	put_cpu_light();
+ #else
+ 	/*
+ 	 * This a non-SMP scenario where the singular Rx thread is
+@@ -1566,11 +1566,11 @@
+ static int fcoe_alloc_paged_crc_eof(struct sk_buff *skb, int tlen)
+ {
+ 	struct fcoe_percpu_s *fps;
+-	int rc;
++	int rc, cpu = get_cpu_light();
+ 
+-	fps = &get_cpu_var(fcoe_percpu);
++	fps = &per_cpu(fcoe_percpu, cpu);
+ 	rc = fcoe_get_paged_crc_eof(skb, tlen, fps);
+-	put_cpu_var(fcoe_percpu);
++	put_cpu_light();
+ 
+ 	return rc;
+ }
+@@ -1768,11 +1768,11 @@
+ 		return 0;
+ 	}
+ 
+-	stats = per_cpu_ptr(lport->stats, get_cpu());
++	stats = per_cpu_ptr(lport->stats, get_cpu_light());
+ 	stats->InvalidCRCCount++;
+ 	if (stats->InvalidCRCCount < 5)
+ 		printk(KERN_WARNING "fcoe: dropping frame with CRC error\n");
+-	put_cpu();
++	put_cpu_light();
+ 	return -EINVAL;
+ }
+ 
+@@ -1848,13 +1848,13 @@
+ 		goto drop;
+ 
+ 	if (!fcoe_filter_frames(lport, fp)) {
+-		put_cpu();
++		put_cpu_light();
+ 		fc_exch_recv(lport, fp);
+ 		return;
+ 	}
+ drop:
+ 	stats->ErrorFrames++;
+-	put_cpu();
++	put_cpu_light();
+ 	kfree_skb(skb);
+ }
+ 
+diff -Nur linux-3.18.8.orig/drivers/scsi/fcoe/fcoe_ctlr.c linux-3.18.8/drivers/scsi/fcoe/fcoe_ctlr.c
+--- linux-3.18.8.orig/drivers/scsi/fcoe/fcoe_ctlr.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/scsi/fcoe/fcoe_ctlr.c	2015-03-03 08:05:18.000000000 +0100
+@@ -831,7 +831,7 @@
+ 
+ 	INIT_LIST_HEAD(&del_list);
+ 
+-	stats = per_cpu_ptr(fip->lp->stats, get_cpu());
++	stats = per_cpu_ptr(fip->lp->stats, get_cpu_light());
+ 
+ 	list_for_each_entry_safe(fcf, next, &fip->fcfs, list) {
+ 		deadline = fcf->time + fcf->fka_period + fcf->fka_period / 2;
+@@ -867,7 +867,7 @@
+ 				sel_time = fcf->time;
+ 		}
+ 	}
+-	put_cpu();
++	put_cpu_light();
+ 
+ 	list_for_each_entry_safe(fcf, next, &del_list, list) {
+ 		/* Removes fcf from current list */
+diff -Nur linux-3.18.8.orig/drivers/scsi/libfc/fc_exch.c linux-3.18.8/drivers/scsi/libfc/fc_exch.c
+--- linux-3.18.8.orig/drivers/scsi/libfc/fc_exch.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/scsi/libfc/fc_exch.c	2015-03-03 08:05:18.000000000 +0100
+@@ -816,10 +816,10 @@
+ 	}
+ 	memset(ep, 0, sizeof(*ep));
+ 
+-	cpu = get_cpu();
++	cpu = get_cpu_light();
+ 	pool = per_cpu_ptr(mp->pool, cpu);
+ 	spin_lock_bh(&pool->lock);
+-	put_cpu();
++	put_cpu_light();
+ 
+ 	/* peek cache of free slot */
+ 	if (pool->left != FC_XID_UNKNOWN) {
+diff -Nur linux-3.18.8.orig/drivers/scsi/libsas/sas_ata.c linux-3.18.8/drivers/scsi/libsas/sas_ata.c
+--- linux-3.18.8.orig/drivers/scsi/libsas/sas_ata.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/scsi/libsas/sas_ata.c	2015-03-03 08:05:18.000000000 +0100
+@@ -191,7 +191,7 @@
+ 	/* TODO: audit callers to ensure they are ready for qc_issue to
+ 	 * unconditionally re-enable interrupts
+ 	 */
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	spin_unlock(ap->lock);
+ 
+ 	/* If the device fell off, no sense in issuing commands */
+@@ -261,7 +261,7 @@
+ 
+  out:
+ 	spin_lock(ap->lock);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 	return ret;
+ }
+ 
+diff -Nur linux-3.18.8.orig/drivers/scsi/qla2xxx/qla_inline.h linux-3.18.8/drivers/scsi/qla2xxx/qla_inline.h
+--- linux-3.18.8.orig/drivers/scsi/qla2xxx/qla_inline.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/scsi/qla2xxx/qla_inline.h	2015-03-03 08:05:18.000000000 +0100
+@@ -59,12 +59,12 @@
+ {
+ 	unsigned long flags;
+ 	struct qla_hw_data *ha = rsp->hw;
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	if (IS_P3P_TYPE(ha))
+ 		qla82xx_poll(0, rsp);
+ 	else
+ 		ha->isp_ops->intr_handler(0, rsp);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ }
+ 
+ static inline uint8_t *
+diff -Nur linux-3.18.8.orig/drivers/tty/serial/8250/8250_core.c linux-3.18.8/drivers/tty/serial/8250/8250_core.c
+--- linux-3.18.8.orig/drivers/tty/serial/8250/8250_core.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/tty/serial/8250/8250_core.c	2015-03-03 08:05:18.000000000 +0100
+@@ -37,6 +37,7 @@
+ #include <linux/nmi.h>
+ #include <linux/mutex.h>
+ #include <linux/slab.h>
++#include <linux/kdb.h>
+ #include <linux/uaccess.h>
+ #include <linux/pm_runtime.h>
+ #ifdef CONFIG_SPARC
+@@ -81,7 +82,16 @@
+ #define DEBUG_INTR(fmt...)	do { } while (0)
+ #endif
+ 
+-#define PASS_LIMIT	512
++/*
++ * On -rt we can have a more delays, and legitimately
++ * so - so don't drop work spuriously and spam the
++ * syslog:
++ */
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define PASS_LIMIT	1000000
++#else
++# define PASS_LIMIT	512
++#endif
+ 
+ #define BOTH_EMPTY 	(UART_LSR_TEMT | UART_LSR_THRE)
+ 
+@@ -3198,7 +3208,7 @@
+ 
+ 	serial8250_rpm_get(up);
+ 
+-	if (port->sysrq || oops_in_progress)
++	if (port->sysrq || oops_in_progress || in_kdb_printk())
+ 		locked = spin_trylock_irqsave(&port->lock, flags);
+ 	else
+ 		spin_lock_irqsave(&port->lock, flags);
+diff -Nur linux-3.18.8.orig/drivers/tty/serial/amba-pl011.c linux-3.18.8/drivers/tty/serial/amba-pl011.c
+--- linux-3.18.8.orig/drivers/tty/serial/amba-pl011.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/tty/serial/amba-pl011.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1935,13 +1935,19 @@
+ 
+ 	clk_enable(uap->clk);
+ 
+-	local_irq_save(flags);
++	/*
++	 * local_irq_save(flags);
++	 *
++	 * This local_irq_save() is nonsense. If we come in via sysrq
++	 * handling then interrupts are already disabled. Aside of
++	 * that the port.sysrq check is racy on SMP regardless.
++	*/
+ 	if (uap->port.sysrq)
+ 		locked = 0;
+ 	else if (oops_in_progress)
+-		locked = spin_trylock(&uap->port.lock);
++		locked = spin_trylock_irqsave(&uap->port.lock, flags);
+ 	else
+-		spin_lock(&uap->port.lock);
++		spin_lock_irqsave(&uap->port.lock, flags);
+ 
+ 	/*
+ 	 *	First save the CR then disable the interrupts
+@@ -1963,8 +1969,7 @@
+ 	writew(old_cr, uap->port.membase + UART011_CR);
+ 
+ 	if (locked)
+-		spin_unlock(&uap->port.lock);
+-	local_irq_restore(flags);
++		spin_unlock_irqrestore(&uap->port.lock, flags);
+ 
+ 	clk_disable(uap->clk);
+ }
+diff -Nur linux-3.18.8.orig/drivers/tty/serial/omap-serial.c linux-3.18.8/drivers/tty/serial/omap-serial.c
+--- linux-3.18.8.orig/drivers/tty/serial/omap-serial.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/tty/serial/omap-serial.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1270,13 +1270,10 @@
+ 
+ 	pm_runtime_get_sync(up->dev);
+ 
+-	local_irq_save(flags);
+-	if (up->port.sysrq)
+-		locked = 0;
+-	else if (oops_in_progress)
+-		locked = spin_trylock(&up->port.lock);
++	if (up->port.sysrq || oops_in_progress)
++		locked = spin_trylock_irqsave(&up->port.lock, flags);
+ 	else
+-		spin_lock(&up->port.lock);
++		spin_lock_irqsave(&up->port.lock, flags);
+ 
+ 	/*
+ 	 * First save the IER then disable the interrupts
+@@ -1305,8 +1302,7 @@
+ 	pm_runtime_mark_last_busy(up->dev);
+ 	pm_runtime_put_autosuspend(up->dev);
+ 	if (locked)
+-		spin_unlock(&up->port.lock);
+-	local_irq_restore(flags);
++		spin_unlock_irqrestore(&up->port.lock, flags);
+ }
+ 
+ static int __init
+diff -Nur linux-3.18.8.orig/drivers/usb/core/hcd.c linux-3.18.8/drivers/usb/core/hcd.c
+--- linux-3.18.8.orig/drivers/usb/core/hcd.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/usb/core/hcd.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1681,9 +1681,9 @@
+ 	 * and no one may trigger the above deadlock situation when
+ 	 * running complete() in tasklet.
+ 	 */
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	urb->complete(urb);
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	usb_anchor_resume_wakeups(anchor);
+ 	atomic_dec(&urb->use_count);
+diff -Nur linux-3.18.8.orig/drivers/usb/gadget/function/f_fs.c linux-3.18.8/drivers/usb/gadget/function/f_fs.c
+--- linux-3.18.8.orig/drivers/usb/gadget/function/f_fs.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/usb/gadget/function/f_fs.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1428,7 +1428,7 @@
+ 		pr_info("%s(): freeing\n", __func__);
+ 		ffs_data_clear(ffs);
+ 		BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
+-		       waitqueue_active(&ffs->ep0req_completion.wait));
++		       swaitqueue_active(&ffs->ep0req_completion.wait));
+ 		kfree(ffs->dev_name);
+ 		kfree(ffs);
+ 	}
+diff -Nur linux-3.18.8.orig/drivers/usb/gadget/legacy/inode.c linux-3.18.8/drivers/usb/gadget/legacy/inode.c
+--- linux-3.18.8.orig/drivers/usb/gadget/legacy/inode.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/drivers/usb/gadget/legacy/inode.c	2015-03-03 08:05:18.000000000 +0100
+@@ -339,7 +339,7 @@
+ 	spin_unlock_irq (&epdata->dev->lock);
+ 
+ 	if (likely (value == 0)) {
+-		value = wait_event_interruptible (done.wait, done.done);
++		value = swait_event_interruptible (done.wait, done.done);
+ 		if (value != 0) {
+ 			spin_lock_irq (&epdata->dev->lock);
+ 			if (likely (epdata->ep != NULL)) {
+@@ -348,7 +348,7 @@
+ 				usb_ep_dequeue (epdata->ep, epdata->req);
+ 				spin_unlock_irq (&epdata->dev->lock);
+ 
+-				wait_event (done.wait, done.done);
++				swait_event (done.wait, done.done);
+ 				if (epdata->status == -ECONNRESET)
+ 					epdata->status = -EINTR;
+ 			} else {
+diff -Nur linux-3.18.8.orig/fs/aio.c linux-3.18.8/fs/aio.c
+--- linux-3.18.8.orig/fs/aio.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/aio.c	2015-03-03 08:05:18.000000000 +0100
+@@ -40,6 +40,7 @@
+ #include <linux/ramfs.h>
+ #include <linux/percpu-refcount.h>
+ #include <linux/mount.h>
++#include <linux/work-simple.h>
+ 
+ #include <asm/kmap_types.h>
+ #include <asm/uaccess.h>
+@@ -110,7 +111,7 @@
+ 	struct page		**ring_pages;
+ 	long			nr_pages;
+ 
+-	struct work_struct	free_work;
++	struct swork_event	free_work;
+ 
+ 	/*
+ 	 * signals when all in-flight requests are done
+@@ -226,6 +227,7 @@
+ 		.mount		= aio_mount,
+ 		.kill_sb	= kill_anon_super,
+ 	};
++	BUG_ON(swork_get());
+ 	aio_mnt = kern_mount(&aio_fs);
+ 	if (IS_ERR(aio_mnt))
+ 		panic("Failed to create aio fs mount.");
+@@ -505,9 +507,9 @@
+ 	return cancel(kiocb);
+ }
+ 
+-static void free_ioctx(struct work_struct *work)
++static void free_ioctx(struct swork_event *sev)
+ {
+-	struct kioctx *ctx = container_of(work, struct kioctx, free_work);
++	struct kioctx *ctx = container_of(sev, struct kioctx, free_work);
+ 
+ 	pr_debug("freeing %p\n", ctx);
+ 
+@@ -526,8 +528,8 @@
+ 	if (ctx->requests_done)
+ 		complete(ctx->requests_done);
+ 
+-	INIT_WORK(&ctx->free_work, free_ioctx);
+-	schedule_work(&ctx->free_work);
++	INIT_SWORK(&ctx->free_work, free_ioctx);
++	swork_queue(&ctx->free_work);
+ }
+ 
+ /*
+@@ -535,9 +537,9 @@
+  * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
+  * now it's safe to cancel any that need to be.
+  */
+-static void free_ioctx_users(struct percpu_ref *ref)
++static void free_ioctx_users_work(struct swork_event *sev)
+ {
+-	struct kioctx *ctx = container_of(ref, struct kioctx, users);
++	struct kioctx *ctx = container_of(sev, struct kioctx, free_work);
+ 	struct kiocb *req;
+ 
+ 	spin_lock_irq(&ctx->ctx_lock);
+@@ -556,6 +558,14 @@
+ 	percpu_ref_put(&ctx->reqs);
+ }
+ 
++static void free_ioctx_users(struct percpu_ref *ref)
++{
++	struct kioctx *ctx = container_of(ref, struct kioctx, users);
++
++	INIT_SWORK(&ctx->free_work, free_ioctx_users_work);
++	swork_queue(&ctx->free_work);
++}
++
+ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
+ {
+ 	unsigned i, new_nr;
+diff -Nur linux-3.18.8.orig/fs/autofs4/autofs_i.h linux-3.18.8/fs/autofs4/autofs_i.h
+--- linux-3.18.8.orig/fs/autofs4/autofs_i.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/autofs4/autofs_i.h	2015-03-03 08:05:18.000000000 +0100
+@@ -34,6 +34,7 @@
+ #include <linux/sched.h>
+ #include <linux/mount.h>
+ #include <linux/namei.h>
++#include <linux/delay.h>
+ #include <asm/current.h>
+ #include <asm/uaccess.h>
+ 
+diff -Nur linux-3.18.8.orig/fs/autofs4/expire.c linux-3.18.8/fs/autofs4/expire.c
+--- linux-3.18.8.orig/fs/autofs4/expire.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/autofs4/expire.c	2015-03-03 08:05:18.000000000 +0100
+@@ -151,7 +151,7 @@
+ 			parent = p->d_parent;
+ 			if (!spin_trylock(&parent->d_lock)) {
+ 				spin_unlock(&p->d_lock);
+-				cpu_relax();
++				cpu_chill();
+ 				goto relock;
+ 			}
+ 			spin_unlock(&p->d_lock);
+diff -Nur linux-3.18.8.orig/fs/buffer.c linux-3.18.8/fs/buffer.c
+--- linux-3.18.8.orig/fs/buffer.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/buffer.c	2015-03-03 08:05:18.000000000 +0100
+@@ -301,8 +301,7 @@
+ 	 * decide that the page is now completely done.
+ 	 */
+ 	first = page_buffers(page);
+-	local_irq_save(flags);
+-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
++	flags = bh_uptodate_lock_irqsave(first);
+ 	clear_buffer_async_read(bh);
+ 	unlock_buffer(bh);
+ 	tmp = bh;
+@@ -315,8 +314,7 @@
+ 		}
+ 		tmp = tmp->b_this_page;
+ 	} while (tmp != bh);
+-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+-	local_irq_restore(flags);
++	bh_uptodate_unlock_irqrestore(first, flags);
+ 
+ 	/*
+ 	 * If none of the buffers had errors and they are all
+@@ -328,9 +326,7 @@
+ 	return;
+ 
+ still_busy:
+-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+-	local_irq_restore(flags);
+-	return;
++	bh_uptodate_unlock_irqrestore(first, flags);
+ }
+ 
+ /*
+@@ -358,8 +354,7 @@
+ 	}
+ 
+ 	first = page_buffers(page);
+-	local_irq_save(flags);
+-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
++	flags = bh_uptodate_lock_irqsave(first);
+ 
+ 	clear_buffer_async_write(bh);
+ 	unlock_buffer(bh);
+@@ -371,15 +366,12 @@
+ 		}
+ 		tmp = tmp->b_this_page;
+ 	}
+-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+-	local_irq_restore(flags);
++	bh_uptodate_unlock_irqrestore(first, flags);
+ 	end_page_writeback(page);
+ 	return;
+ 
+ still_busy:
+-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+-	local_irq_restore(flags);
+-	return;
++	bh_uptodate_unlock_irqrestore(first, flags);
+ }
+ EXPORT_SYMBOL(end_buffer_async_write);
+ 
+@@ -3325,6 +3317,7 @@
+ 	struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags);
+ 	if (ret) {
+ 		INIT_LIST_HEAD(&ret->b_assoc_buffers);
++		buffer_head_init_locks(ret);
+ 		preempt_disable();
+ 		__this_cpu_inc(bh_accounting.nr);
+ 		recalc_bh_state();
+diff -Nur linux-3.18.8.orig/fs/dcache.c linux-3.18.8/fs/dcache.c
+--- linux-3.18.8.orig/fs/dcache.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/dcache.c	2015-03-03 08:05:18.000000000 +0100
+@@ -19,6 +19,7 @@
+ #include <linux/mm.h>
+ #include <linux/fs.h>
+ #include <linux/fsnotify.h>
++#include <linux/delay.h>
+ #include <linux/slab.h>
+ #include <linux/init.h>
+ #include <linux/hash.h>
+@@ -552,7 +553,7 @@
+ 
+ failed:
+ 	spin_unlock(&dentry->d_lock);
+-	cpu_relax();
++	cpu_chill();
+ 	return dentry; /* try again with same dentry */
+ }
+ 
+@@ -2285,7 +2286,7 @@
+ 	if (dentry->d_lockref.count == 1) {
+ 		if (!spin_trylock(&inode->i_lock)) {
+ 			spin_unlock(&dentry->d_lock);
+-			cpu_relax();
++			cpu_chill();
+ 			goto again;
+ 		}
+ 		dentry->d_flags &= ~DCACHE_CANT_MOUNT;
+diff -Nur linux-3.18.8.orig/fs/eventpoll.c linux-3.18.8/fs/eventpoll.c
+--- linux-3.18.8.orig/fs/eventpoll.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/eventpoll.c	2015-03-03 08:05:18.000000000 +0100
+@@ -505,12 +505,12 @@
+  */
+ static void ep_poll_safewake(wait_queue_head_t *wq)
+ {
+-	int this_cpu = get_cpu();
++	int this_cpu = get_cpu_light();
+ 
+ 	ep_call_nested(&poll_safewake_ncalls, EP_MAX_NESTS,
+ 		       ep_poll_wakeup_proc, NULL, wq, (void *) (long) this_cpu);
+ 
+-	put_cpu();
++	put_cpu_light();
+ }
+ 
+ static void ep_remove_wait_queue(struct eppoll_entry *pwq)
+diff -Nur linux-3.18.8.orig/fs/exec.c linux-3.18.8/fs/exec.c
+--- linux-3.18.8.orig/fs/exec.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/exec.c	2015-03-03 08:05:18.000000000 +0100
+@@ -841,12 +841,14 @@
+ 		}
+ 	}
+ 	task_lock(tsk);
++	preempt_disable_rt();
+ 	active_mm = tsk->active_mm;
+ 	tsk->mm = mm;
+ 	tsk->active_mm = mm;
+ 	activate_mm(active_mm, mm);
+ 	tsk->mm->vmacache_seqnum = 0;
+ 	vmacache_flush(tsk);
++	preempt_enable_rt();
+ 	task_unlock(tsk);
+ 	if (old_mm) {
+ 		up_read(&old_mm->mmap_sem);
+diff -Nur linux-3.18.8.orig/fs/jbd/checkpoint.c linux-3.18.8/fs/jbd/checkpoint.c
+--- linux-3.18.8.orig/fs/jbd/checkpoint.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/jbd/checkpoint.c	2015-03-03 08:05:18.000000000 +0100
+@@ -129,6 +129,8 @@
+ 		if (journal->j_flags & JFS_ABORT)
+ 			return;
+ 		spin_unlock(&journal->j_state_lock);
++		if (current->plug)
++			io_schedule();
+ 		mutex_lock(&journal->j_checkpoint_mutex);
+ 
+ 		/*
+diff -Nur linux-3.18.8.orig/fs/jbd2/checkpoint.c linux-3.18.8/fs/jbd2/checkpoint.c
+--- linux-3.18.8.orig/fs/jbd2/checkpoint.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/jbd2/checkpoint.c	2015-03-03 08:05:18.000000000 +0100
+@@ -116,6 +116,8 @@
+ 	nblocks = jbd2_space_needed(journal);
+ 	while (jbd2_log_space_left(journal) < nblocks) {
+ 		write_unlock(&journal->j_state_lock);
++		if (current->plug)
++			io_schedule();
+ 		mutex_lock(&journal->j_checkpoint_mutex);
+ 
+ 		/*
+diff -Nur linux-3.18.8.orig/fs/namespace.c linux-3.18.8/fs/namespace.c
+--- linux-3.18.8.orig/fs/namespace.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/namespace.c	2015-03-03 08:05:18.000000000 +0100
+@@ -14,6 +14,7 @@
+ #include <linux/mnt_namespace.h>
+ #include <linux/user_namespace.h>
+ #include <linux/namei.h>
++#include <linux/delay.h>
+ #include <linux/security.h>
+ #include <linux/idr.h>
+ #include <linux/init.h>		/* init_rootfs */
+@@ -344,8 +345,11 @@
+ 	 * incremented count after it has set MNT_WRITE_HOLD.
+ 	 */
+ 	smp_mb();
+-	while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD)
+-		cpu_relax();
++	while (ACCESS_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
++		preempt_enable();
++		cpu_chill();
++		preempt_disable();
++	}
+ 	/*
+ 	 * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
+ 	 * be set to match its requirements. So we must not load that until
+diff -Nur linux-3.18.8.orig/fs/ntfs/aops.c linux-3.18.8/fs/ntfs/aops.c
+--- linux-3.18.8.orig/fs/ntfs/aops.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/ntfs/aops.c	2015-03-03 08:05:18.000000000 +0100
+@@ -107,8 +107,7 @@
+ 				"0x%llx.", (unsigned long long)bh->b_blocknr);
+ 	}
+ 	first = page_buffers(page);
+-	local_irq_save(flags);
+-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
++	flags = bh_uptodate_lock_irqsave(first);
+ 	clear_buffer_async_read(bh);
+ 	unlock_buffer(bh);
+ 	tmp = bh;
+@@ -123,8 +122,7 @@
+ 		}
+ 		tmp = tmp->b_this_page;
+ 	} while (tmp != bh);
+-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+-	local_irq_restore(flags);
++	bh_uptodate_unlock_irqrestore(first, flags);
+ 	/*
+ 	 * If none of the buffers had errors then we can set the page uptodate,
+ 	 * but we first have to perform the post read mst fixups, if the
+@@ -145,13 +143,13 @@
+ 		recs = PAGE_CACHE_SIZE / rec_size;
+ 		/* Should have been verified before we got here... */
+ 		BUG_ON(!recs);
+-		local_irq_save(flags);
++		local_irq_save_nort(flags);
+ 		kaddr = kmap_atomic(page);
+ 		for (i = 0; i < recs; i++)
+ 			post_read_mst_fixup((NTFS_RECORD*)(kaddr +
+ 					i * rec_size), rec_size);
+ 		kunmap_atomic(kaddr);
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ 		flush_dcache_page(page);
+ 		if (likely(page_uptodate && !PageError(page)))
+ 			SetPageUptodate(page);
+@@ -159,9 +157,7 @@
+ 	unlock_page(page);
+ 	return;
+ still_busy:
+-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+-	local_irq_restore(flags);
+-	return;
++	bh_uptodate_unlock_irqrestore(first, flags);
+ }
+ 
+ /**
+diff -Nur linux-3.18.8.orig/fs/timerfd.c linux-3.18.8/fs/timerfd.c
+--- linux-3.18.8.orig/fs/timerfd.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/fs/timerfd.c	2015-03-03 08:05:18.000000000 +0100
+@@ -449,7 +449,10 @@
+ 				break;
+ 		}
+ 		spin_unlock_irq(&ctx->wqh.lock);
+-		cpu_relax();
++		if (isalarm(ctx))
++			hrtimer_wait_for_timer(&ctx->t.alarm.timer);
++		else
++			hrtimer_wait_for_timer(&ctx->t.tmr);
+ 	}
+ 
+ 	/*
+diff -Nur linux-3.18.8.orig/include/acpi/platform/aclinux.h linux-3.18.8/include/acpi/platform/aclinux.h
+--- linux-3.18.8.orig/include/acpi/platform/aclinux.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/acpi/platform/aclinux.h	2015-03-03 08:05:18.000000000 +0100
+@@ -123,6 +123,7 @@
+ 
+ #define acpi_cache_t                        struct kmem_cache
+ #define acpi_spinlock                       spinlock_t *
++#define acpi_raw_spinlock		raw_spinlock_t *
+ #define acpi_cpu_flags                      unsigned long
+ 
+ /* Use native linux version of acpi_os_allocate_zeroed */
+@@ -141,6 +142,20 @@
+ #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_get_thread_id
+ #define ACPI_USE_ALTERNATE_PROTOTYPE_acpi_os_create_lock
+ 
++#define acpi_os_create_raw_lock(__handle)			\
++({								\
++	 raw_spinlock_t *lock = ACPI_ALLOCATE(sizeof(*lock));	\
++								\
++	 if (lock) {						\
++		*(__handle) = lock;				\
++		raw_spin_lock_init(*(__handle));		\
++	 }							\
++	 lock ? AE_OK : AE_NO_MEMORY;				\
++ })
++
++#define acpi_os_delete_raw_lock(__handle)	kfree(__handle)
++
++
+ /*
+  * OSL interfaces used by debugger/disassembler
+  */
+diff -Nur linux-3.18.8.orig/include/asm-generic/bug.h linux-3.18.8/include/asm-generic/bug.h
+--- linux-3.18.8.orig/include/asm-generic/bug.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/asm-generic/bug.h	2015-03-03 08:05:18.000000000 +0100
+@@ -206,6 +206,20 @@
+ # define WARN_ON_SMP(x)			({0;})
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++# define BUG_ON_RT(c)			BUG_ON(c)
++# define BUG_ON_NONRT(c)		do { } while (0)
++# define WARN_ON_RT(condition)		WARN_ON(condition)
++# define WARN_ON_NONRT(condition)	do { } while (0)
++# define WARN_ON_ONCE_NONRT(condition)	do { } while (0)
++#else
++# define BUG_ON_RT(c)			do { } while (0)
++# define BUG_ON_NONRT(c)		BUG_ON(c)
++# define WARN_ON_RT(condition)		do { } while (0)
++# define WARN_ON_NONRT(condition)	WARN_ON(condition)
++# define WARN_ON_ONCE_NONRT(condition)	WARN_ON_ONCE(condition)
++#endif
++
+ #endif /* __ASSEMBLY__ */
+ 
+ #endif
+diff -Nur linux-3.18.8.orig/include/linux/blkdev.h linux-3.18.8/include/linux/blkdev.h
+--- linux-3.18.8.orig/include/linux/blkdev.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/blkdev.h	2015-03-03 08:05:18.000000000 +0100
+@@ -101,6 +101,7 @@
+ 	struct list_head queuelist;
+ 	union {
+ 		struct call_single_data csd;
++		struct work_struct work;
+ 		unsigned long fifo_time;
+ 	};
+ 
+@@ -478,7 +479,7 @@
+ 	struct throtl_data *td;
+ #endif
+ 	struct rcu_head		rcu_head;
+-	wait_queue_head_t	mq_freeze_wq;
++	struct swait_head	mq_freeze_wq;
+ 	struct percpu_ref	mq_usage_counter;
+ 	struct list_head	all_q_node;
+ 
+diff -Nur linux-3.18.8.orig/include/linux/blk-mq.h linux-3.18.8/include/linux/blk-mq.h
+--- linux-3.18.8.orig/include/linux/blk-mq.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/blk-mq.h	2015-03-03 08:05:18.000000000 +0100
+@@ -169,6 +169,7 @@
+ 
+ struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *, const int ctx_index);
+ struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_tag_set *, unsigned int, int);
++void __blk_mq_complete_request_remote_work(struct work_struct *work);
+ 
+ void blk_mq_start_request(struct request *rq);
+ void blk_mq_end_request(struct request *rq, int error);
+diff -Nur linux-3.18.8.orig/include/linux/bottom_half.h linux-3.18.8/include/linux/bottom_half.h
+--- linux-3.18.8.orig/include/linux/bottom_half.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/bottom_half.h	2015-03-03 08:05:18.000000000 +0100
+@@ -4,6 +4,17 @@
+ #include <linux/preempt.h>
+ #include <linux/preempt_mask.h>
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++
++extern void local_bh_disable(void);
++extern void _local_bh_enable(void);
++extern void local_bh_enable(void);
++extern void local_bh_enable_ip(unsigned long ip);
++extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
++extern void __local_bh_enable_ip(unsigned long ip, unsigned int cnt);
++
++#else
++
+ #ifdef CONFIG_TRACE_IRQFLAGS
+ extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
+ #else
+@@ -31,5 +42,6 @@
+ {
+ 	__local_bh_enable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
+ }
++#endif
+ 
+ #endif /* _LINUX_BH_H */
+diff -Nur linux-3.18.8.orig/include/linux/buffer_head.h linux-3.18.8/include/linux/buffer_head.h
+--- linux-3.18.8.orig/include/linux/buffer_head.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/buffer_head.h	2015-03-03 08:05:18.000000000 +0100
+@@ -75,8 +75,52 @@
+ 	struct address_space *b_assoc_map;	/* mapping this buffer is
+ 						   associated with */
+ 	atomic_t b_count;		/* users using this buffer_head */
++#ifdef CONFIG_PREEMPT_RT_BASE
++	spinlock_t b_uptodate_lock;
++#if defined(CONFIG_JBD) || defined(CONFIG_JBD_MODULE) || \
++	defined(CONFIG_JBD2) || defined(CONFIG_JBD2_MODULE)
++	spinlock_t b_state_lock;
++	spinlock_t b_journal_head_lock;
++#endif
++#endif
+ };
+ 
++static inline unsigned long bh_uptodate_lock_irqsave(struct buffer_head *bh)
++{
++	unsigned long flags;
++
++#ifndef CONFIG_PREEMPT_RT_BASE
++	local_irq_save(flags);
++	bit_spin_lock(BH_Uptodate_Lock, &bh->b_state);
++#else
++	spin_lock_irqsave(&bh->b_uptodate_lock, flags);
++#endif
++	return flags;
++}
++
++static inline void
++bh_uptodate_unlock_irqrestore(struct buffer_head *bh, unsigned long flags)
++{
++#ifndef CONFIG_PREEMPT_RT_BASE
++	bit_spin_unlock(BH_Uptodate_Lock, &bh->b_state);
++	local_irq_restore(flags);
++#else
++	spin_unlock_irqrestore(&bh->b_uptodate_lock, flags);
++#endif
++}
++
++static inline void buffer_head_init_locks(struct buffer_head *bh)
++{
++#ifdef CONFIG_PREEMPT_RT_BASE
++	spin_lock_init(&bh->b_uptodate_lock);
++#if defined(CONFIG_JBD) || defined(CONFIG_JBD_MODULE) || \
++	defined(CONFIG_JBD2) || defined(CONFIG_JBD2_MODULE)
++	spin_lock_init(&bh->b_state_lock);
++	spin_lock_init(&bh->b_journal_head_lock);
++#endif
++#endif
++}
++
+ /*
+  * macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
+  * and buffer_foo() functions.
+diff -Nur linux-3.18.8.orig/include/linux/cgroup.h linux-3.18.8/include/linux/cgroup.h
+--- linux-3.18.8.orig/include/linux/cgroup.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/cgroup.h	2015-03-03 08:05:18.000000000 +0100
+@@ -22,6 +22,7 @@
+ #include <linux/seq_file.h>
+ #include <linux/kernfs.h>
+ #include <linux/wait.h>
++#include <linux/work-simple.h>
+ 
+ #ifdef CONFIG_CGROUPS
+ 
+@@ -91,6 +92,7 @@
+ 	/* percpu_ref killing and RCU release */
+ 	struct rcu_head rcu_head;
+ 	struct work_struct destroy_work;
++	struct swork_event destroy_swork;
+ };
+ 
+ /* bits in struct cgroup_subsys_state flags field */
+diff -Nur linux-3.18.8.orig/include/linux/completion.h linux-3.18.8/include/linux/completion.h
+--- linux-3.18.8.orig/include/linux/completion.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/completion.h	2015-03-03 08:05:18.000000000 +0100
+@@ -7,8 +7,7 @@
+  * Atomic wait-for-completion handler data structures.
+  * See kernel/sched/completion.c for details.
+  */
+-
+-#include <linux/wait.h>
++#include <linux/wait-simple.h>
+ 
+ /*
+  * struct completion - structure used to maintain state for a "completion"
+@@ -24,11 +23,11 @@
+  */
+ struct completion {
+ 	unsigned int done;
+-	wait_queue_head_t wait;
++	struct swait_head wait;
+ };
+ 
+ #define COMPLETION_INITIALIZER(work) \
+-	{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
++	{ 0, SWAIT_HEAD_INITIALIZER((work).wait) }
+ 
+ #define COMPLETION_INITIALIZER_ONSTACK(work) \
+ 	({ init_completion(&work); work; })
+@@ -73,7 +72,7 @@
+ static inline void init_completion(struct completion *x)
+ {
+ 	x->done = 0;
+-	init_waitqueue_head(&x->wait);
++	init_swait_head(&x->wait);
+ }
+ 
+ /**
+diff -Nur linux-3.18.8.orig/include/linux/cpu.h linux-3.18.8/include/linux/cpu.h
+--- linux-3.18.8.orig/include/linux/cpu.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/cpu.h	2015-03-03 08:05:18.000000000 +0100
+@@ -217,6 +217,8 @@
+ extern void put_online_cpus(void);
+ extern void cpu_hotplug_disable(void);
+ extern void cpu_hotplug_enable(void);
++extern void pin_current_cpu(void);
++extern void unpin_current_cpu(void);
+ #define hotcpu_notifier(fn, pri)	cpu_notifier(fn, pri)
+ #define __hotcpu_notifier(fn, pri)	__cpu_notifier(fn, pri)
+ #define register_hotcpu_notifier(nb)	register_cpu_notifier(nb)
+@@ -235,6 +237,8 @@
+ #define put_online_cpus()	do { } while (0)
+ #define cpu_hotplug_disable()	do { } while (0)
+ #define cpu_hotplug_enable()	do { } while (0)
++static inline void pin_current_cpu(void) { }
++static inline void unpin_current_cpu(void) { }
+ #define hotcpu_notifier(fn, pri)	do { (void)(fn); } while (0)
+ #define __hotcpu_notifier(fn, pri)	do { (void)(fn); } while (0)
+ /* These aren't inline functions due to a GCC bug. */
+diff -Nur linux-3.18.8.orig/include/linux/delay.h linux-3.18.8/include/linux/delay.h
+--- linux-3.18.8.orig/include/linux/delay.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/delay.h	2015-03-03 08:05:18.000000000 +0100
+@@ -52,4 +52,10 @@
+ 	msleep(seconds * 1000);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++extern void cpu_chill(void);
++#else
++# define cpu_chill()	cpu_relax()
++#endif
++
+ #endif /* defined(_LINUX_DELAY_H) */
+diff -Nur linux-3.18.8.orig/include/linux/ftrace_event.h linux-3.18.8/include/linux/ftrace_event.h
+--- linux-3.18.8.orig/include/linux/ftrace_event.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/ftrace_event.h	2015-03-03 08:05:18.000000000 +0100
+@@ -61,6 +61,9 @@
+ 	unsigned char		flags;
+ 	unsigned char		preempt_count;
+ 	int			pid;
++	unsigned short		migrate_disable;
++	unsigned short		padding;
++	unsigned char		preempt_lazy_count;
+ };
+ 
+ #define FTRACE_MAX_EVENT						\
+diff -Nur linux-3.18.8.orig/include/linux/highmem.h linux-3.18.8/include/linux/highmem.h
+--- linux-3.18.8.orig/include/linux/highmem.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/highmem.h	2015-03-03 08:05:18.000000000 +0100
+@@ -7,6 +7,7 @@
+ #include <linux/mm.h>
+ #include <linux/uaccess.h>
+ #include <linux/hardirq.h>
++#include <linux/sched.h>
+ 
+ #include <asm/cacheflush.h>
+ 
+@@ -85,32 +86,51 @@
+ 
+ #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ DECLARE_PER_CPU(int, __kmap_atomic_idx);
++#endif
+ 
+ static inline int kmap_atomic_idx_push(void)
+ {
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
+ 
+-#ifdef CONFIG_DEBUG_HIGHMEM
++# ifdef CONFIG_DEBUG_HIGHMEM
+ 	WARN_ON_ONCE(in_irq() && !irqs_disabled());
+ 	BUG_ON(idx >= KM_TYPE_NR);
+-#endif
++# endif
+ 	return idx;
++#else
++	current->kmap_idx++;
++	BUG_ON(current->kmap_idx > KM_TYPE_NR);
++	return current->kmap_idx - 1;
++#endif
+ }
+ 
+ static inline int kmap_atomic_idx(void)
+ {
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	return __this_cpu_read(__kmap_atomic_idx) - 1;
++#else
++	return current->kmap_idx - 1;
++#endif
+ }
+ 
+ static inline void kmap_atomic_idx_pop(void)
+ {
+-#ifdef CONFIG_DEBUG_HIGHMEM
++#ifndef CONFIG_PREEMPT_RT_FULL
++# ifdef CONFIG_DEBUG_HIGHMEM
+ 	int idx = __this_cpu_dec_return(__kmap_atomic_idx);
+ 
+ 	BUG_ON(idx < 0);
+-#else
++# else
+ 	__this_cpu_dec(__kmap_atomic_idx);
++# endif
++#else
++	current->kmap_idx--;
++# ifdef CONFIG_DEBUG_HIGHMEM
++	BUG_ON(current->kmap_idx < 0);
++# endif
+ #endif
+ }
+ 
+diff -Nur linux-3.18.8.orig/include/linux/hrtimer.h linux-3.18.8/include/linux/hrtimer.h
+--- linux-3.18.8.orig/include/linux/hrtimer.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/hrtimer.h	2015-03-03 08:05:18.000000000 +0100
+@@ -111,6 +111,11 @@
+ 	enum hrtimer_restart		(*function)(struct hrtimer *);
+ 	struct hrtimer_clock_base	*base;
+ 	unsigned long			state;
++	struct list_head		cb_entry;
++	int				irqsafe;
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++	ktime_t				praecox;
++#endif
+ #ifdef CONFIG_TIMER_STATS
+ 	int				start_pid;
+ 	void				*start_site;
+@@ -147,6 +152,7 @@
+ 	int			index;
+ 	clockid_t		clockid;
+ 	struct timerqueue_head	active;
++	struct list_head	expired;
+ 	ktime_t			resolution;
+ 	ktime_t			(*get_time)(void);
+ 	ktime_t			softirq_time;
+@@ -192,6 +198,9 @@
+ 	unsigned long			nr_hangs;
+ 	ktime_t				max_hang_time;
+ #endif
++#ifdef CONFIG_PREEMPT_RT_BASE
++	wait_queue_head_t		wait;
++#endif
+ 	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];
+ };
+ 
+@@ -379,6 +388,13 @@
+ 	return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
+ }
+ 
++/* Softirq preemption could deadlock timer removal */
++#ifdef CONFIG_PREEMPT_RT_BASE
++  extern void hrtimer_wait_for_timer(const struct hrtimer *timer);
++#else
++# define hrtimer_wait_for_timer(timer)	do { cpu_relax(); } while (0)
++#endif
++
+ /* Query timers: */
+ extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
+ extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
+diff -Nur linux-3.18.8.orig/include/linux/idr.h linux-3.18.8/include/linux/idr.h
+--- linux-3.18.8.orig/include/linux/idr.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/idr.h	2015-03-03 08:05:18.000000000 +0100
+@@ -95,10 +95,14 @@
+  * Each idr_preload() should be matched with an invocation of this
+  * function.  See idr_preload() for details.
+  */
++#ifdef CONFIG_PREEMPT_RT_FULL
++void idr_preload_end(void);
++#else
+ static inline void idr_preload_end(void)
+ {
+ 	preempt_enable();
+ }
++#endif
+ 
+ /**
+  * idr_find - return pointer for given id
+diff -Nur linux-3.18.8.orig/include/linux/init_task.h linux-3.18.8/include/linux/init_task.h
+--- linux-3.18.8.orig/include/linux/init_task.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/init_task.h	2015-03-03 08:05:18.000000000 +0100
+@@ -147,9 +147,16 @@
+ # define INIT_PERF_EVENTS(tsk)
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++# define INIT_TIMER_LIST		.posix_timer_list = NULL,
++#else
++# define INIT_TIMER_LIST
++#endif
++
+ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+ # define INIT_VTIME(tsk)						\
+-	.vtime_seqlock = __SEQLOCK_UNLOCKED(tsk.vtime_seqlock),	\
++	.vtime_lock = __RAW_SPIN_LOCK_UNLOCKED(tsk.vtime_lock),	\
++	.vtime_seq = SEQCNT_ZERO(tsk.vtime_seq),			\
+ 	.vtime_snap = 0,				\
+ 	.vtime_snap_whence = VTIME_SYS,
+ #else
+@@ -219,6 +226,7 @@
+ 	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\
+ 	.pi_lock	= __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock),	\
+ 	.timer_slack_ns = 50000, /* 50 usec default slack */		\
++	INIT_TIMER_LIST							\
+ 	.pids = {							\
+ 		[PIDTYPE_PID]  = INIT_PID_LINK(PIDTYPE_PID),		\
+ 		[PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID),		\
+diff -Nur linux-3.18.8.orig/include/linux/interrupt.h linux-3.18.8/include/linux/interrupt.h
+--- linux-3.18.8.orig/include/linux/interrupt.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/interrupt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -57,6 +57,7 @@
+  * IRQF_NO_THREAD - Interrupt cannot be threaded
+  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
+  *                resume time.
++ * IRQF_NO_SOFTIRQ_CALL - Do not process softirqs in the irq thread context (RT)
+  */
+ #define IRQF_DISABLED		0x00000020
+ #define IRQF_SHARED		0x00000080
+@@ -70,6 +71,7 @@
+ #define IRQF_FORCE_RESUME	0x00008000
+ #define IRQF_NO_THREAD		0x00010000
+ #define IRQF_EARLY_RESUME	0x00020000
++#define IRQF_NO_SOFTIRQ_CALL	0x00080000
+ 
+ #define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
+ 
+@@ -180,7 +182,7 @@
+ #ifdef CONFIG_LOCKDEP
+ # define local_irq_enable_in_hardirq()	do { } while (0)
+ #else
+-# define local_irq_enable_in_hardirq()	local_irq_enable()
++# define local_irq_enable_in_hardirq()	local_irq_enable_nort()
+ #endif
+ 
+ extern void disable_irq_nosync(unsigned int irq);
+@@ -210,6 +212,7 @@
+ 	unsigned int irq;
+ 	struct kref kref;
+ 	struct work_struct work;
++	struct list_head list;
+ 	void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
+ 	void (*release)(struct kref *ref);
+ };
+@@ -358,9 +361,13 @@
+ 
+ 
+ #ifdef CONFIG_IRQ_FORCED_THREADING
++# ifndef CONFIG_PREEMPT_RT_BASE
+ extern bool force_irqthreads;
++# else
++#  define force_irqthreads	(true)
++# endif
+ #else
+-#define force_irqthreads	(0)
++#define force_irqthreads	(false)
+ #endif
+ 
+ #ifndef __ARCH_SET_SOFTIRQ_PENDING
+@@ -416,9 +423,10 @@
+ 	void	(*action)(struct softirq_action *);
+ };
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ asmlinkage void do_softirq(void);
+ asmlinkage void __do_softirq(void);
+-
++static inline void thread_do_softirq(void) { do_softirq(); }
+ #ifdef __ARCH_HAS_DO_SOFTIRQ
+ void do_softirq_own_stack(void);
+ #else
+@@ -427,6 +435,9 @@
+ 	__do_softirq();
+ }
+ #endif
++#else
++extern void thread_do_softirq(void);
++#endif
+ 
+ extern void open_softirq(int nr, void (*action)(struct softirq_action *));
+ extern void softirq_init(void);
+@@ -434,6 +445,7 @@
+ 
+ extern void raise_softirq_irqoff(unsigned int nr);
+ extern void raise_softirq(unsigned int nr);
++extern void softirq_check_pending_idle(void);
+ 
+ DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
+ 
+@@ -455,8 +467,9 @@
+      to be executed on some cpu at least once after this.
+    * If the tasklet is already scheduled, but its execution is still not
+      started, it will be executed only once.
+-   * If this tasklet is already running on another CPU (or schedule is called
+-     from tasklet itself), it is rescheduled for later.
++   * If this tasklet is already running on another CPU, it is rescheduled
++     for later.
++   * Schedule must not be called from the tasklet itself (a lockup occurs)
+    * Tasklet is strictly serialized wrt itself, but not
+      wrt another tasklets. If client needs some intertask synchronization,
+      he makes it with spinlocks.
+@@ -481,27 +494,36 @@
+ enum
+ {
+ 	TASKLET_STATE_SCHED,	/* Tasklet is scheduled for execution */
+-	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
++	TASKLET_STATE_RUN,	/* Tasklet is running (SMP only) */
++	TASKLET_STATE_PENDING	/* Tasklet is pending */
+ };
+ 
+-#ifdef CONFIG_SMP
++#define TASKLET_STATEF_SCHED	(1 << TASKLET_STATE_SCHED)
++#define TASKLET_STATEF_RUN	(1 << TASKLET_STATE_RUN)
++#define TASKLET_STATEF_PENDING	(1 << TASKLET_STATE_PENDING)
++
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
+ static inline int tasklet_trylock(struct tasklet_struct *t)
+ {
+ 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
+ }
+ 
++static inline int tasklet_tryunlock(struct tasklet_struct *t)
++{
++	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
++}
++
+ static inline void tasklet_unlock(struct tasklet_struct *t)
+ {
+ 	smp_mb__before_atomic();
+ 	clear_bit(TASKLET_STATE_RUN, &(t)->state);
+ }
+ 
+-static inline void tasklet_unlock_wait(struct tasklet_struct *t)
+-{
+-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
+-}
++extern void tasklet_unlock_wait(struct tasklet_struct *t);
++
+ #else
+ #define tasklet_trylock(t) 1
++#define tasklet_tryunlock(t)	1
+ #define tasklet_unlock_wait(t) do { } while (0)
+ #define tasklet_unlock(t) do { } while (0)
+ #endif
+@@ -550,17 +572,8 @@
+ 	smp_mb();
+ }
+ 
+-static inline void tasklet_enable(struct tasklet_struct *t)
+-{
+-	smp_mb__before_atomic();
+-	atomic_dec(&t->count);
+-}
+-
+-static inline void tasklet_hi_enable(struct tasklet_struct *t)
+-{
+-	smp_mb__before_atomic();
+-	atomic_dec(&t->count);
+-}
++extern void tasklet_enable(struct tasklet_struct *t);
++extern void tasklet_hi_enable(struct tasklet_struct *t);
+ 
+ extern void tasklet_kill(struct tasklet_struct *t);
+ extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
+@@ -592,6 +605,12 @@
+ 	tasklet_kill(&ttimer->tasklet);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++extern void softirq_early_init(void);
++#else
++static inline void softirq_early_init(void) { }
++#endif
++
+ /*
+  * Autoprobing for irqs:
+  *
+diff -Nur linux-3.18.8.orig/include/linux/irqdesc.h linux-3.18.8/include/linux/irqdesc.h
+--- linux-3.18.8.orig/include/linux/irqdesc.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/irqdesc.h	2015-03-03 08:05:18.000000000 +0100
+@@ -63,6 +63,7 @@
+ 	unsigned int		irqs_unhandled;
+ 	atomic_t		threads_handled;
+ 	int			threads_handled_last;
++	u64			random_ip;
+ 	raw_spinlock_t		lock;
+ 	struct cpumask		*percpu_enabled;
+ #ifdef CONFIG_SMP
+diff -Nur linux-3.18.8.orig/include/linux/irqflags.h linux-3.18.8/include/linux/irqflags.h
+--- linux-3.18.8.orig/include/linux/irqflags.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/irqflags.h	2015-03-03 08:05:18.000000000 +0100
+@@ -25,8 +25,6 @@
+ # define trace_softirqs_enabled(p)	((p)->softirqs_enabled)
+ # define trace_hardirq_enter()	do { current->hardirq_context++; } while (0)
+ # define trace_hardirq_exit()	do { current->hardirq_context--; } while (0)
+-# define lockdep_softirq_enter()	do { current->softirq_context++; } while (0)
+-# define lockdep_softirq_exit()	do { current->softirq_context--; } while (0)
+ # define INIT_TRACE_IRQFLAGS	.softirqs_enabled = 1,
+ #else
+ # define trace_hardirqs_on()		do { } while (0)
+@@ -39,9 +37,15 @@
+ # define trace_softirqs_enabled(p)	0
+ # define trace_hardirq_enter()		do { } while (0)
+ # define trace_hardirq_exit()		do { } while (0)
++# define INIT_TRACE_IRQFLAGS
++#endif
++
++#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT_FULL)
++# define lockdep_softirq_enter() do { current->softirq_context++; } while (0)
++# define lockdep_softirq_exit()	 do { current->softirq_context--; } while (0)
++#else
+ # define lockdep_softirq_enter()	do { } while (0)
+ # define lockdep_softirq_exit()		do { } while (0)
+-# define INIT_TRACE_IRQFLAGS
+ #endif
+ 
+ #if defined(CONFIG_IRQSOFF_TRACER) || \
+@@ -147,4 +151,23 @@
+ 
+ #endif /* CONFIG_TRACE_IRQFLAGS_SUPPORT */
+ 
++/*
++ * local_irq* variants depending on RT/!RT
++ */
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define local_irq_disable_nort()	do { } while (0)
++# define local_irq_enable_nort()	do { } while (0)
++# define local_irq_save_nort(flags)	local_save_flags(flags)
++# define local_irq_restore_nort(flags)	(void)(flags)
++# define local_irq_disable_rt()		local_irq_disable()
++# define local_irq_enable_rt()		local_irq_enable()
++#else
++# define local_irq_disable_nort()	local_irq_disable()
++# define local_irq_enable_nort()	local_irq_enable()
++# define local_irq_save_nort(flags)	local_irq_save(flags)
++# define local_irq_restore_nort(flags)	local_irq_restore(flags)
++# define local_irq_disable_rt()		do { } while (0)
++# define local_irq_enable_rt()		do { } while (0)
++#endif
++
+ #endif
+diff -Nur linux-3.18.8.orig/include/linux/irq.h linux-3.18.8/include/linux/irq.h
+--- linux-3.18.8.orig/include/linux/irq.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/irq.h	2015-03-03 08:05:18.000000000 +0100
+@@ -73,6 +73,7 @@
+  * IRQ_IS_POLLED		- Always polled by another interrupt. Exclude
+  *				  it from the spurious interrupt detection
+  *				  mechanism and from core side polling.
++ * IRQ_NO_SOFTIRQ_CALL		- No softirq processing in the irq thread context (RT)
+  */
+ enum {
+ 	IRQ_TYPE_NONE		= 0x00000000,
+@@ -98,13 +99,14 @@
+ 	IRQ_NOTHREAD		= (1 << 16),
+ 	IRQ_PER_CPU_DEVID	= (1 << 17),
+ 	IRQ_IS_POLLED		= (1 << 18),
++	IRQ_NO_SOFTIRQ_CALL     = (1 << 19),
+ };
+ 
+ #define IRQF_MODIFY_MASK	\
+ 	(IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \
+ 	 IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \
+ 	 IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \
+-	 IRQ_IS_POLLED)
++	 IRQ_IS_POLLED | IRQ_NO_SOFTIRQ_CALL)
+ 
+ #define IRQ_NO_BALANCING_MASK	(IRQ_PER_CPU | IRQ_NO_BALANCING)
+ 
+diff -Nur linux-3.18.8.orig/include/linux/irq_work.h linux-3.18.8/include/linux/irq_work.h
+--- linux-3.18.8.orig/include/linux/irq_work.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/irq_work.h	2015-03-03 08:05:18.000000000 +0100
+@@ -16,6 +16,7 @@
+ #define IRQ_WORK_BUSY		2UL
+ #define IRQ_WORK_FLAGS		3UL
+ #define IRQ_WORK_LAZY		4UL /* Doesn't want IPI, wait for tick */
++#define IRQ_WORK_HARD_IRQ	8UL /* Run hard IRQ context, even on RT */
+ 
+ struct irq_work {
+ 	unsigned long flags;
+diff -Nur linux-3.18.8.orig/include/linux/jbd_common.h linux-3.18.8/include/linux/jbd_common.h
+--- linux-3.18.8.orig/include/linux/jbd_common.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/jbd_common.h	2015-03-03 08:05:18.000000000 +0100
+@@ -15,32 +15,56 @@
+ 
+ static inline void jbd_lock_bh_state(struct buffer_head *bh)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	bit_spin_lock(BH_State, &bh->b_state);
++#else
++	spin_lock(&bh->b_state_lock);
++#endif
+ }
+ 
+ static inline int jbd_trylock_bh_state(struct buffer_head *bh)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	return bit_spin_trylock(BH_State, &bh->b_state);
++#else
++	return spin_trylock(&bh->b_state_lock);
++#endif
+ }
+ 
+ static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	return bit_spin_is_locked(BH_State, &bh->b_state);
++#else
++	return spin_is_locked(&bh->b_state_lock);
++#endif
+ }
+ 
+ static inline void jbd_unlock_bh_state(struct buffer_head *bh)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	bit_spin_unlock(BH_State, &bh->b_state);
++#else
++	spin_unlock(&bh->b_state_lock);
++#endif
+ }
+ 
+ static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	bit_spin_lock(BH_JournalHead, &bh->b_state);
++#else
++	spin_lock(&bh->b_journal_head_lock);
++#endif
+ }
+ 
+ static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	bit_spin_unlock(BH_JournalHead, &bh->b_state);
++#else
++	spin_unlock(&bh->b_journal_head_lock);
++#endif
+ }
+ 
+ #endif
+diff -Nur linux-3.18.8.orig/include/linux/jump_label.h linux-3.18.8/include/linux/jump_label.h
+--- linux-3.18.8.orig/include/linux/jump_label.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/jump_label.h	2015-03-03 08:05:18.000000000 +0100
+@@ -55,7 +55,8 @@
+ 				    "%s used before call to jump_label_init", \
+ 				    __func__)
+ 
+-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
++#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) && \
++	!defined(CONFIG_PREEMPT_BASE)
+ 
+ struct static_key {
+ 	atomic_t enabled;
+diff -Nur linux-3.18.8.orig/include/linux/kdb.h linux-3.18.8/include/linux/kdb.h
+--- linux-3.18.8.orig/include/linux/kdb.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/kdb.h	2015-03-03 08:05:18.000000000 +0100
+@@ -116,7 +116,7 @@
+ extern __printf(1, 0) int vkdb_printf(const char *fmt, va_list args);
+ extern __printf(1, 2) int kdb_printf(const char *, ...);
+ typedef __printf(1, 2) int (*kdb_printf_t)(const char *, ...);
+-
++#define in_kdb_printk() (kdb_trap_printk)
+ extern void kdb_init(int level);
+ 
+ /* Access to kdb specific polling devices */
+@@ -151,6 +151,7 @@
+ extern int kdb_unregister(char *);
+ #else /* ! CONFIG_KGDB_KDB */
+ static inline __printf(1, 2) int kdb_printf(const char *fmt, ...) { return 0; }
++#define in_kdb_printk() (0)
+ static inline void kdb_init(int level) {}
+ static inline int kdb_register(char *cmd, kdb_func_t func, char *usage,
+ 			       char *help, short minlen) { return 0; }
+diff -Nur linux-3.18.8.orig/include/linux/kernel.h linux-3.18.8/include/linux/kernel.h
+--- linux-3.18.8.orig/include/linux/kernel.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/kernel.h	2015-03-03 08:05:18.000000000 +0100
+@@ -451,6 +451,7 @@
+ 	SYSTEM_HALT,
+ 	SYSTEM_POWER_OFF,
+ 	SYSTEM_RESTART,
++	SYSTEM_SUSPEND,
+ } system_state;
+ 
+ #define TAINT_PROPRIETARY_MODULE	0
+diff -Nur linux-3.18.8.orig/include/linux/lglock.h linux-3.18.8/include/linux/lglock.h
+--- linux-3.18.8.orig/include/linux/lglock.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/lglock.h	2015-03-03 08:05:18.000000000 +0100
+@@ -34,22 +34,39 @@
+ #endif
+ 
+ struct lglock {
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	arch_spinlock_t __percpu *lock;
++#else
++	struct rt_mutex __percpu *lock;
++#endif
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 	struct lock_class_key lock_key;
+ 	struct lockdep_map    lock_dep_map;
+ #endif
+ };
+ 
+-#define DEFINE_LGLOCK(name)						\
++#ifndef CONFIG_PREEMPT_RT_FULL
++# define DEFINE_LGLOCK(name)						\
+ 	static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock)		\
+ 	= __ARCH_SPIN_LOCK_UNLOCKED;					\
+ 	struct lglock name = { .lock = &name ## _lock }
+ 
+-#define DEFINE_STATIC_LGLOCK(name)					\
++# define DEFINE_STATIC_LGLOCK(name)					\
+ 	static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock)		\
+ 	= __ARCH_SPIN_LOCK_UNLOCKED;					\
+ 	static struct lglock name = { .lock = &name ## _lock }
++#else
++
++# define DEFINE_LGLOCK(name)						\
++	static DEFINE_PER_CPU(struct rt_mutex, name ## _lock)		\
++	= __RT_MUTEX_INITIALIZER( name ## _lock);			\
++	struct lglock name = { .lock = &name ## _lock }
++
++# define DEFINE_STATIC_LGLOCK(name)					\
++	static DEFINE_PER_CPU(struct rt_mutex, name ## _lock)		\
++	= __RT_MUTEX_INITIALIZER( name ## _lock);			\
++	static struct lglock name = { .lock = &name ## _lock }
++#endif
+ 
+ void lg_lock_init(struct lglock *lg, char *name);
+ void lg_local_lock(struct lglock *lg);
+@@ -59,6 +76,12 @@
+ void lg_global_lock(struct lglock *lg);
+ void lg_global_unlock(struct lglock *lg);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++#define lg_global_trylock_relax(name)	lg_global_lock(name)
++#else
++void lg_global_trylock_relax(struct lglock *lg);
++#endif
++
+ #else
+ /* When !CONFIG_SMP, map lglock to spinlock */
+ #define lglock spinlock
+diff -Nur linux-3.18.8.orig/include/linux/list_bl.h linux-3.18.8/include/linux/list_bl.h
+--- linux-3.18.8.orig/include/linux/list_bl.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/list_bl.h	2015-03-03 08:05:18.000000000 +0100
+@@ -2,6 +2,7 @@
+ #define _LINUX_LIST_BL_H
+ 
+ #include <linux/list.h>
++#include <linux/spinlock.h>
+ #include <linux/bit_spinlock.h>
+ 
+ /*
+@@ -32,13 +33,22 @@
+ 
+ struct hlist_bl_head {
+ 	struct hlist_bl_node *first;
++#ifdef CONFIG_PREEMPT_RT_BASE
++	raw_spinlock_t lock;
++#endif
+ };
+ 
+ struct hlist_bl_node {
+ 	struct hlist_bl_node *next, **pprev;
+ };
+-#define INIT_HLIST_BL_HEAD(ptr) \
+-	((ptr)->first = NULL)
++
++static inline void INIT_HLIST_BL_HEAD(struct hlist_bl_head *h)
++{
++	h->first = NULL;
++#ifdef CONFIG_PREEMPT_RT_BASE
++	raw_spin_lock_init(&h->lock);
++#endif
++}
+ 
+ static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h)
+ {
+@@ -117,12 +127,26 @@
+ 
+ static inline void hlist_bl_lock(struct hlist_bl_head *b)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	bit_spin_lock(0, (unsigned long *)b);
++#else
++	raw_spin_lock(&b->lock);
++#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
++	__set_bit(0, (unsigned long *)b);
++#endif
++#endif
+ }
+ 
+ static inline void hlist_bl_unlock(struct hlist_bl_head *b)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	__bit_spin_unlock(0, (unsigned long *)b);
++#else
++#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
++	__clear_bit(0, (unsigned long *)b);
++#endif
++	raw_spin_unlock(&b->lock);
++#endif
+ }
+ 
+ static inline bool hlist_bl_is_locked(struct hlist_bl_head *b)
+diff -Nur linux-3.18.8.orig/include/linux/locallock.h linux-3.18.8/include/linux/locallock.h
+--- linux-3.18.8.orig/include/linux/locallock.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/locallock.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,270 @@
++#ifndef _LINUX_LOCALLOCK_H
++#define _LINUX_LOCALLOCK_H
++
++#include <linux/percpu.h>
++#include <linux/spinlock.h>
++
++#ifdef CONFIG_PREEMPT_RT_BASE
++
++#ifdef CONFIG_DEBUG_SPINLOCK
++# define LL_WARN(cond)	WARN_ON(cond)
++#else
++# define LL_WARN(cond)	do { } while (0)
++#endif
++
++/*
++ * per cpu lock based substitute for local_irq_*()
++ */
++struct local_irq_lock {
++	spinlock_t		lock;
++	struct task_struct	*owner;
++	int			nestcnt;
++	unsigned long		flags;
++};
++
++#define DEFINE_LOCAL_IRQ_LOCK(lvar)					\
++	DEFINE_PER_CPU(struct local_irq_lock, lvar) = {			\
++		.lock = __SPIN_LOCK_UNLOCKED((lvar).lock) }
++
++#define DECLARE_LOCAL_IRQ_LOCK(lvar)					\
++	DECLARE_PER_CPU(struct local_irq_lock, lvar)
++
++#define local_irq_lock_init(lvar)					\
++	do {								\
++		int __cpu;						\
++		for_each_possible_cpu(__cpu)				\
++			spin_lock_init(&per_cpu(lvar, __cpu).lock);	\
++	} while (0)
++
++/*
++ * spin_lock|trylock|unlock_local flavour that does not migrate disable
++ * used for __local_lock|trylock|unlock where get_local_var/put_local_var
++ * already takes care of the migrate_disable/enable
++ * for CONFIG_PREEMPT_BASE map to the normal spin_* calls.
++ */
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define spin_lock_local(lock)			rt_spin_lock(lock)
++# define spin_trylock_local(lock)		rt_spin_trylock(lock)
++# define spin_unlock_local(lock)		rt_spin_unlock(lock)
++#else
++# define spin_lock_local(lock)			spin_lock(lock)
++# define spin_trylock_local(lock)		spin_trylock(lock)
++# define spin_unlock_local(lock)		spin_unlock(lock)
++#endif
++
++static inline void __local_lock(struct local_irq_lock *lv)
++{
++	if (lv->owner != current) {
++		spin_lock_local(&lv->lock);
++		LL_WARN(lv->owner);
++		LL_WARN(lv->nestcnt);
++		lv->owner = current;
++	}
++	lv->nestcnt++;
++}
++
++#define local_lock(lvar)					\
++	do { __local_lock(&get_local_var(lvar)); } while (0)
++
++static inline int __local_trylock(struct local_irq_lock *lv)
++{
++	if (lv->owner != current && spin_trylock_local(&lv->lock)) {
++		LL_WARN(lv->owner);
++		LL_WARN(lv->nestcnt);
++		lv->owner = current;
++		lv->nestcnt = 1;
++		return 1;
++	}
++	return 0;
++}
++
++#define local_trylock(lvar)						\
++	({								\
++		int __locked;						\
++		__locked = __local_trylock(&get_local_var(lvar));	\
++		if (!__locked)						\
++			put_local_var(lvar);				\
++		__locked;						\
++	})
++
++static inline void __local_unlock(struct local_irq_lock *lv)
++{
++	LL_WARN(lv->nestcnt == 0);
++	LL_WARN(lv->owner != current);
++	if (--lv->nestcnt)
++		return;
++
++	lv->owner = NULL;
++	spin_unlock_local(&lv->lock);
++}
++
++#define local_unlock(lvar)					\
++	do {							\
++		__local_unlock(&__get_cpu_var(lvar));		\
++		put_local_var(lvar);				\
++	} while (0)
++
++static inline void __local_lock_irq(struct local_irq_lock *lv)
++{
++	spin_lock_irqsave(&lv->lock, lv->flags);
++	LL_WARN(lv->owner);
++	LL_WARN(lv->nestcnt);
++	lv->owner = current;
++	lv->nestcnt = 1;
++}
++
++#define local_lock_irq(lvar)						\
++	do { __local_lock_irq(&get_local_var(lvar)); } while (0)
++
++#define local_lock_irq_on(lvar, cpu)					\
++	do { __local_lock_irq(&per_cpu(lvar, cpu)); } while (0)
++
++static inline void __local_unlock_irq(struct local_irq_lock *lv)
++{
++	LL_WARN(!lv->nestcnt);
++	LL_WARN(lv->owner != current);
++	lv->owner = NULL;
++	lv->nestcnt = 0;
++	spin_unlock_irq(&lv->lock);
++}
++
++#define local_unlock_irq(lvar)						\
++	do {								\
++		__local_unlock_irq(&__get_cpu_var(lvar));		\
++		put_local_var(lvar);					\
++	} while (0)
++
++#define local_unlock_irq_on(lvar, cpu)					\
++	do {								\
++		__local_unlock_irq(&per_cpu(lvar, cpu));		\
++	} while (0)
++
++static inline int __local_lock_irqsave(struct local_irq_lock *lv)
++{
++	if (lv->owner != current) {
++		__local_lock_irq(lv);
++		return 0;
++	} else {
++		lv->nestcnt++;
++		return 1;
++	}
++}
++
++#define local_lock_irqsave(lvar, _flags)				\
++	do {								\
++		if (__local_lock_irqsave(&get_local_var(lvar)))		\
++			put_local_var(lvar);				\
++		_flags = __get_cpu_var(lvar).flags;			\
++	} while (0)
++
++#define local_lock_irqsave_on(lvar, _flags, cpu)			\
++	do {								\
++		__local_lock_irqsave(&per_cpu(lvar, cpu));		\
++		_flags = per_cpu(lvar, cpu).flags;			\
++	} while (0)
++
++static inline int __local_unlock_irqrestore(struct local_irq_lock *lv,
++					    unsigned long flags)
++{
++	LL_WARN(!lv->nestcnt);
++	LL_WARN(lv->owner != current);
++	if (--lv->nestcnt)
++		return 0;
++
++	lv->owner = NULL;
++	spin_unlock_irqrestore(&lv->lock, lv->flags);
++	return 1;
++}
++
++#define local_unlock_irqrestore(lvar, flags)				\
++	do {								\
++		if (__local_unlock_irqrestore(&__get_cpu_var(lvar), flags)) \
++			put_local_var(lvar);				\
++	} while (0)
++
++#define local_unlock_irqrestore_on(lvar, flags, cpu)			\
++	do {								\
++		__local_unlock_irqrestore(&per_cpu(lvar, cpu), flags);	\
++	} while (0)
++
++#define local_spin_trylock_irq(lvar, lock)				\
++	({								\
++		int __locked;						\
++		local_lock_irq(lvar);					\
++		__locked = spin_trylock(lock);				\
++		if (!__locked)						\
++			local_unlock_irq(lvar);				\
++		__locked;						\
++	})
++
++#define local_spin_lock_irq(lvar, lock)					\
++	do {								\
++		local_lock_irq(lvar);					\
++		spin_lock(lock);					\
++	} while (0)
++
++#define local_spin_unlock_irq(lvar, lock)				\
++	do {								\
++		spin_unlock(lock);					\
++		local_unlock_irq(lvar);					\
++	} while (0)
++
++#define local_spin_lock_irqsave(lvar, lock, flags)			\
++	do {								\
++		local_lock_irqsave(lvar, flags);			\
++		spin_lock(lock);					\
++	} while (0)
++
++#define local_spin_unlock_irqrestore(lvar, lock, flags)			\
++	do {								\
++		spin_unlock(lock);					\
++		local_unlock_irqrestore(lvar, flags);			\
++	} while (0)
++
++#define get_locked_var(lvar, var)					\
++	(*({								\
++		local_lock(lvar);					\
++		&__get_cpu_var(var);					\
++	}))
++
++#define put_locked_var(lvar, var)	local_unlock(lvar);
++
++#define local_lock_cpu(lvar)						\
++	({								\
++		local_lock(lvar);					\
++		smp_processor_id();					\
++	})
++
++#define local_unlock_cpu(lvar)			local_unlock(lvar)
++
++#else /* PREEMPT_RT_BASE */
++
++#define DEFINE_LOCAL_IRQ_LOCK(lvar)		__typeof__(const int) lvar
++#define DECLARE_LOCAL_IRQ_LOCK(lvar)		extern __typeof__(const int) lvar
++
++static inline void local_irq_lock_init(int lvar) { }
++
++#define local_lock(lvar)			preempt_disable()
++#define local_unlock(lvar)			preempt_enable()
++#define local_lock_irq(lvar)			local_irq_disable()
++#define local_unlock_irq(lvar)			local_irq_enable()
++#define local_lock_irqsave(lvar, flags)		local_irq_save(flags)
++#define local_unlock_irqrestore(lvar, flags)	local_irq_restore(flags)
++
++#define local_spin_trylock_irq(lvar, lock)	spin_trylock_irq(lock)
++#define local_spin_lock_irq(lvar, lock)		spin_lock_irq(lock)
++#define local_spin_unlock_irq(lvar, lock)	spin_unlock_irq(lock)
++#define local_spin_lock_irqsave(lvar, lock, flags)	\
++	spin_lock_irqsave(lock, flags)
++#define local_spin_unlock_irqrestore(lvar, lock, flags)	\
++	spin_unlock_irqrestore(lock, flags)
++
++#define get_locked_var(lvar, var)		get_cpu_var(var)
++#define put_locked_var(lvar, var)		put_cpu_var(var)
++
++#define local_lock_cpu(lvar)			get_cpu()
++#define local_unlock_cpu(lvar)			put_cpu()
++
++#endif
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/mm_types.h linux-3.18.8/include/linux/mm_types.h
+--- linux-3.18.8.orig/include/linux/mm_types.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/mm_types.h	2015-03-03 08:05:18.000000000 +0100
+@@ -11,6 +11,7 @@
+ #include <linux/completion.h>
+ #include <linux/cpumask.h>
+ #include <linux/page-debug-flags.h>
++#include <linux/rcupdate.h>
+ #include <linux/uprobes.h>
+ #include <linux/page-flags-layout.h>
+ #include <asm/page.h>
+@@ -454,6 +455,9 @@
+ 	bool tlb_flush_pending;
+ #endif
+ 	struct uprobes_state uprobes_state;
++#ifdef CONFIG_PREEMPT_RT_BASE
++	struct rcu_head delayed_drop;
++#endif
+ };
+ 
+ static inline void mm_init_cpumask(struct mm_struct *mm)
+diff -Nur linux-3.18.8.orig/include/linux/mutex.h linux-3.18.8/include/linux/mutex.h
+--- linux-3.18.8.orig/include/linux/mutex.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/mutex.h	2015-03-03 08:05:18.000000000 +0100
+@@ -19,6 +19,17 @@
+ #include <asm/processor.h>
+ #include <linux/osq_lock.h>
+ 
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
++	, .dep_map = { .name = #lockname }
++#else
++# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
++#endif
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++# include <linux/mutex_rt.h>
++#else
++
+ /*
+  * Simple, straightforward mutexes with strict semantics:
+  *
+@@ -100,13 +111,6 @@
+ static inline void mutex_destroy(struct mutex *lock) {}
+ #endif
+ 
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
+-		, .dep_map = { .name = #lockname }
+-#else
+-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
+-#endif
+-
+ #define __MUTEX_INITIALIZER(lockname) \
+ 		{ .count = ATOMIC_INIT(1) \
+ 		, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
+@@ -174,6 +178,8 @@
+ extern int mutex_trylock(struct mutex *lock);
+ extern void mutex_unlock(struct mutex *lock);
+ 
++#endif /* !PREEMPT_RT_FULL */
++
+ extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
+ 
+ #endif /* __LINUX_MUTEX_H */
+diff -Nur linux-3.18.8.orig/include/linux/mutex_rt.h linux-3.18.8/include/linux/mutex_rt.h
+--- linux-3.18.8.orig/include/linux/mutex_rt.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/mutex_rt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,84 @@
++#ifndef __LINUX_MUTEX_RT_H
++#define __LINUX_MUTEX_RT_H
++
++#ifndef __LINUX_MUTEX_H
++#error "Please include mutex.h"
++#endif
++
++#include <linux/rtmutex.h>
++
++/* FIXME: Just for __lockfunc */
++#include <linux/spinlock.h>
++
++struct mutex {
++	struct rt_mutex		lock;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++};
++
++#define __MUTEX_INITIALIZER(mutexname)					\
++	{								\
++		.lock = __RT_MUTEX_INITIALIZER(mutexname.lock)		\
++		__DEP_MAP_MUTEX_INITIALIZER(mutexname)			\
++	}
++
++#define DEFINE_MUTEX(mutexname)						\
++	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
++
++extern void __mutex_do_init(struct mutex *lock, const char *name, struct lock_class_key *key);
++extern void __lockfunc _mutex_lock(struct mutex *lock);
++extern int __lockfunc _mutex_lock_interruptible(struct mutex *lock);
++extern int __lockfunc _mutex_lock_killable(struct mutex *lock);
++extern void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass);
++extern void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock);
++extern int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass);
++extern int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass);
++extern int __lockfunc _mutex_trylock(struct mutex *lock);
++extern void __lockfunc _mutex_unlock(struct mutex *lock);
++
++#define mutex_is_locked(l)		rt_mutex_is_locked(&(l)->lock)
++#define mutex_lock(l)			_mutex_lock(l)
++#define mutex_lock_interruptible(l)	_mutex_lock_interruptible(l)
++#define mutex_lock_killable(l)		_mutex_lock_killable(l)
++#define mutex_trylock(l)		_mutex_trylock(l)
++#define mutex_unlock(l)			_mutex_unlock(l)
++#define mutex_destroy(l)		rt_mutex_destroy(&(l)->lock)
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define mutex_lock_nested(l, s)	_mutex_lock_nested(l, s)
++# define mutex_lock_interruptible_nested(l, s) \
++					_mutex_lock_interruptible_nested(l, s)
++# define mutex_lock_killable_nested(l, s) \
++					_mutex_lock_killable_nested(l, s)
++
++# define mutex_lock_nest_lock(lock, nest_lock)				\
++do {									\
++	typecheck(struct lockdep_map *, &(nest_lock)->dep_map);		\
++	_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map);		\
++} while (0)
++
++#else
++# define mutex_lock_nested(l, s)	_mutex_lock(l)
++# define mutex_lock_interruptible_nested(l, s) \
++					_mutex_lock_interruptible(l)
++# define mutex_lock_killable_nested(l, s) \
++					_mutex_lock_killable(l)
++# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
++#endif
++
++# define mutex_init(mutex)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	rt_mutex_init(&(mutex)->lock);			\
++	__mutex_do_init((mutex), #mutex, &__key);	\
++} while (0)
++
++# define __mutex_init(mutex, name, key)			\
++do {							\
++	rt_mutex_init(&(mutex)->lock);			\
++	__mutex_do_init((mutex), name, key);		\
++} while (0)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/netdevice.h linux-3.18.8/include/linux/netdevice.h
+--- linux-3.18.8.orig/include/linux/netdevice.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/netdevice.h	2015-03-03 08:05:18.000000000 +0100
+@@ -2345,6 +2345,7 @@
+ 	unsigned int		dropped;
+ 	struct sk_buff_head	input_pkt_queue;
+ 	struct napi_struct	backlog;
++	struct sk_buff_head	tofree_queue;
+ 
+ #ifdef CONFIG_NET_FLOW_LIMIT
+ 	struct sd_flow_limit __rcu *flow_limit;
+diff -Nur linux-3.18.8.orig/include/linux/netfilter/x_tables.h linux-3.18.8/include/linux/netfilter/x_tables.h
+--- linux-3.18.8.orig/include/linux/netfilter/x_tables.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/netfilter/x_tables.h	2015-03-03 08:05:18.000000000 +0100
+@@ -3,6 +3,7 @@
+ 
+ 
+ #include <linux/netdevice.h>
++#include <linux/locallock.h>
+ #include <uapi/linux/netfilter/x_tables.h>
+ 
+ /**
+@@ -282,6 +283,8 @@
+  */
+ DECLARE_PER_CPU(seqcount_t, xt_recseq);
+ 
++DECLARE_LOCAL_IRQ_LOCK(xt_write_lock);
++
+ /**
+  * xt_write_recseq_begin - start of a write section
+  *
+@@ -296,6 +299,9 @@
+ {
+ 	unsigned int addend;
+ 
++	/* RT protection */
++	local_lock(xt_write_lock);
++
+ 	/*
+ 	 * Low order bit of sequence is set if we already
+ 	 * called xt_write_recseq_begin().
+@@ -326,6 +332,7 @@
+ 	/* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
+ 	smp_wmb();
+ 	__this_cpu_add(xt_recseq.sequence, addend);
++	local_unlock(xt_write_lock);
+ }
+ 
+ /*
+diff -Nur linux-3.18.8.orig/include/linux/notifier.h linux-3.18.8/include/linux/notifier.h
+--- linux-3.18.8.orig/include/linux/notifier.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/notifier.h	2015-03-03 08:05:18.000000000 +0100
+@@ -6,7 +6,7 @@
+  *
+  *				Alan Cox <Alan.Cox@linux.org>
+  */
+- 
++
+ #ifndef _LINUX_NOTIFIER_H
+ #define _LINUX_NOTIFIER_H
+ #include <linux/errno.h>
+@@ -42,9 +42,7 @@
+  * in srcu_notifier_call_chain(): no cache bounces and no memory barriers.
+  * As compensation, srcu_notifier_chain_unregister() is rather expensive.
+  * SRCU notifier chains should be used when the chain will be called very
+- * often but notifier_blocks will seldom be removed.  Also, SRCU notifier
+- * chains are slightly more difficult to use because they require special
+- * runtime initialization.
++ * often but notifier_blocks will seldom be removed.
+  */
+ 
+ typedef	int (*notifier_fn_t)(struct notifier_block *nb,
+@@ -88,7 +86,7 @@
+ 		(name)->head = NULL;		\
+ 	} while (0)
+ 
+-/* srcu_notifier_heads must be initialized and cleaned up dynamically */
++/* srcu_notifier_heads must be cleaned up dynamically */
+ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
+ #define srcu_cleanup_notifier_head(name)	\
+ 		cleanup_srcu_struct(&(name)->srcu);
+@@ -101,7 +99,13 @@
+ 		.head = NULL }
+ #define RAW_NOTIFIER_INIT(name)	{				\
+ 		.head = NULL }
+-/* srcu_notifier_heads cannot be initialized statically */
++
++#define SRCU_NOTIFIER_INIT(name, pcpu)				\
++	{							\
++		.mutex = __MUTEX_INITIALIZER(name.mutex),	\
++		.head = NULL,					\
++		.srcu = __SRCU_STRUCT_INIT(name.srcu, pcpu),	\
++	}
+ 
+ #define ATOMIC_NOTIFIER_HEAD(name)				\
+ 	struct atomic_notifier_head name =			\
+@@ -113,6 +117,18 @@
+ 	struct raw_notifier_head name =				\
+ 		RAW_NOTIFIER_INIT(name)
+ 
++#define _SRCU_NOTIFIER_HEAD(name, mod)				\
++	static DEFINE_PER_CPU(struct srcu_struct_array,		\
++			name##_head_srcu_array);		\
++	mod struct srcu_notifier_head name =			\
++			SRCU_NOTIFIER_INIT(name, name##_head_srcu_array)
++
++#define SRCU_NOTIFIER_HEAD(name)				\
++	_SRCU_NOTIFIER_HEAD(name, )
++
++#define SRCU_NOTIFIER_HEAD_STATIC(name)				\
++	_SRCU_NOTIFIER_HEAD(name, static)
++
+ #ifdef __KERNEL__
+ 
+ extern int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
+@@ -182,12 +198,12 @@
+ 
+ /*
+  *	Declared notifiers so far. I can imagine quite a few more chains
+- *	over time (eg laptop power reset chains, reboot chain (to clean 
++ *	over time (eg laptop power reset chains, reboot chain (to clean
+  *	device units up), device [un]mount chain, module load/unload chain,
+- *	low memory chain, screenblank chain (for plug in modular screenblankers) 
++ *	low memory chain, screenblank chain (for plug in modular screenblankers)
+  *	VC switch chains (for loadable kernel svgalib VC switch helpers) etc...
+  */
+- 
++
+ /* CPU notfiers are defined in include/linux/cpu.h. */
+ 
+ /* netdevice notifiers are defined in include/linux/netdevice.h */
+diff -Nur linux-3.18.8.orig/include/linux/percpu.h linux-3.18.8/include/linux/percpu.h
+--- linux-3.18.8.orig/include/linux/percpu.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/percpu.h	2015-03-03 08:05:18.000000000 +0100
+@@ -23,6 +23,35 @@
+ 	 PERCPU_MODULE_RESERVE)
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++
++#define get_local_var(var) (*({		\
++	       migrate_disable();	\
++	       &__get_cpu_var(var);	}))
++
++#define put_local_var(var) do {	\
++	(void)&(var);		\
++	migrate_enable();	\
++} while (0)
++
++# define get_local_ptr(var) ({		\
++		migrate_disable();	\
++		this_cpu_ptr(var);	})
++
++# define put_local_ptr(var) do {	\
++	(void)(var);			\
++	migrate_enable();		\
++} while (0)
++
++#else
++
++#define get_local_var(var)	get_cpu_var(var)
++#define put_local_var(var)	put_cpu_var(var)
++#define get_local_ptr(var)	get_cpu_ptr(var)
++#define put_local_ptr(var)	put_cpu_ptr(var)
++
++#endif
++
+ /* minimum unit size, also is the maximum supported allocation size */
+ #define PCPU_MIN_UNIT_SIZE		PFN_ALIGN(32 << 10)
+ 
+diff -Nur linux-3.18.8.orig/include/linux/pid.h linux-3.18.8/include/linux/pid.h
+--- linux-3.18.8.orig/include/linux/pid.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/pid.h	2015-03-03 08:05:18.000000000 +0100
+@@ -2,6 +2,7 @@
+ #define _LINUX_PID_H
+ 
+ #include <linux/rcupdate.h>
++#include <linux/atomic.h>
+ 
+ enum pid_type
+ {
+diff -Nur linux-3.18.8.orig/include/linux/preempt.h linux-3.18.8/include/linux/preempt.h
+--- linux-3.18.8.orig/include/linux/preempt.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/preempt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -33,6 +33,20 @@
+ #define preempt_count_inc() preempt_count_add(1)
+ #define preempt_count_dec() preempt_count_sub(1)
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++#define add_preempt_lazy_count(val)	do { preempt_lazy_count() += (val); } while (0)
++#define sub_preempt_lazy_count(val)	do { preempt_lazy_count() -= (val); } while (0)
++#define inc_preempt_lazy_count()	add_preempt_lazy_count(1)
++#define dec_preempt_lazy_count()	sub_preempt_lazy_count(1)
++#define preempt_lazy_count()		(current_thread_info()->preempt_lazy_count)
++#else
++#define add_preempt_lazy_count(val)	do { } while (0)
++#define sub_preempt_lazy_count(val)	do { } while (0)
++#define inc_preempt_lazy_count()	do { } while (0)
++#define dec_preempt_lazy_count()	do { } while (0)
++#define preempt_lazy_count()		(0)
++#endif
++
+ #ifdef CONFIG_PREEMPT_COUNT
+ 
+ #define preempt_disable() \
+@@ -41,13 +55,25 @@
+ 	barrier(); \
+ } while (0)
+ 
++#define preempt_lazy_disable() \
++do { \
++	inc_preempt_lazy_count(); \
++	barrier(); \
++} while (0)
++
+ #define sched_preempt_enable_no_resched() \
+ do { \
+ 	barrier(); \
+ 	preempt_count_dec(); \
+ } while (0)
+ 
+-#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
++#ifdef CONFIG_PREEMPT_RT_BASE
++# define preempt_enable_no_resched() sched_preempt_enable_no_resched()
++# define preempt_check_resched_rt() preempt_check_resched()
++#else
++# define preempt_enable_no_resched() preempt_enable()
++# define preempt_check_resched_rt() barrier();
++#endif
+ 
+ #ifdef CONFIG_PREEMPT
+ #define preempt_enable() \
+@@ -63,6 +89,13 @@
+ 		__preempt_schedule(); \
+ } while (0)
+ 
++#define preempt_lazy_enable() \
++do { \
++	dec_preempt_lazy_count(); \
++	barrier(); \
++	preempt_check_resched(); \
++} while (0)
++
+ #else
+ #define preempt_enable() \
+ do { \
+@@ -121,6 +154,7 @@
+ #define preempt_disable_notrace()		barrier()
+ #define preempt_enable_no_resched_notrace()	barrier()
+ #define preempt_enable_notrace()		barrier()
++#define preempt_check_resched_rt()		barrier()
+ 
+ #endif /* CONFIG_PREEMPT_COUNT */
+ 
+@@ -140,10 +174,31 @@
+ } while (0)
+ #define preempt_fold_need_resched() \
+ do { \
+-	if (tif_need_resched()) \
++	if (tif_need_resched_now()) \
+ 		set_preempt_need_resched(); \
+ } while (0)
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define preempt_disable_rt()		preempt_disable()
++# define preempt_enable_rt()		preempt_enable()
++# define preempt_disable_nort()		barrier()
++# define preempt_enable_nort()		barrier()
++# ifdef CONFIG_SMP
++   extern void migrate_disable(void);
++   extern void migrate_enable(void);
++# else /* CONFIG_SMP */
++#  define migrate_disable()		barrier()
++#  define migrate_enable()		barrier()
++# endif /* CONFIG_SMP */
++#else
++# define preempt_disable_rt()		barrier()
++# define preempt_enable_rt()		barrier()
++# define preempt_disable_nort()		preempt_disable()
++# define preempt_enable_nort()		preempt_enable()
++# define migrate_disable()		preempt_disable()
++# define migrate_enable()		preempt_enable()
++#endif
++
+ #ifdef CONFIG_PREEMPT_NOTIFIERS
+ 
+ struct preempt_notifier;
+diff -Nur linux-3.18.8.orig/include/linux/preempt_mask.h linux-3.18.8/include/linux/preempt_mask.h
+--- linux-3.18.8.orig/include/linux/preempt_mask.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/preempt_mask.h	2015-03-03 08:05:18.000000000 +0100
+@@ -44,16 +44,26 @@
+ #define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)
+ #define NMI_OFFSET	(1UL << NMI_SHIFT)
+ 
+-#define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)
++#ifndef CONFIG_PREEMPT_RT_FULL
++# define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)
++#else
++# define SOFTIRQ_DISABLE_OFFSET	(0)
++#endif
+ 
+ #define PREEMPT_ACTIVE_BITS	1
+ #define PREEMPT_ACTIVE_SHIFT	(NMI_SHIFT + NMI_BITS)
+ #define PREEMPT_ACTIVE	(__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
+ 
+ #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
+-#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
+ #define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
+ 				 | NMI_MASK))
++#ifndef CONFIG_PREEMPT_RT_FULL
++# define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
++# define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
++#else
++# define softirq_count()	(0UL)
++extern int in_serving_softirq(void);
++#endif
+ 
+ /*
+  * Are we doing bottom half or hardware interrupt processing?
+@@ -64,7 +74,6 @@
+ #define in_irq()		(hardirq_count())
+ #define in_softirq()		(softirq_count())
+ #define in_interrupt()		(irq_count())
+-#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
+ 
+ /*
+  * Are we in NMI context?
+diff -Nur linux-3.18.8.orig/include/linux/printk.h linux-3.18.8/include/linux/printk.h
+--- linux-3.18.8.orig/include/linux/printk.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/printk.h	2015-03-03 08:05:18.000000000 +0100
+@@ -119,9 +119,11 @@
+ extern asmlinkage __printf(1, 2)
+ void early_printk(const char *fmt, ...);
+ void early_vprintk(const char *fmt, va_list ap);
++extern void printk_kill(void);
+ #else
+ static inline __printf(1, 2) __cold
+ void early_printk(const char *s, ...) { }
++static inline void printk_kill(void) { }
+ #endif
+ 
+ #ifdef CONFIG_PRINTK
+@@ -155,7 +157,6 @@
+ #define printk_ratelimit() __printk_ratelimit(__func__)
+ extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
+ 				   unsigned int interval_msec);
+-
+ extern int printk_delay_msec;
+ extern int dmesg_restrict;
+ extern int kptr_restrict;
+diff -Nur linux-3.18.8.orig/include/linux/radix-tree.h linux-3.18.8/include/linux/radix-tree.h
+--- linux-3.18.8.orig/include/linux/radix-tree.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/radix-tree.h	2015-03-03 08:05:18.000000000 +0100
+@@ -277,8 +277,13 @@
+ unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
+ 			void ***results, unsigned long *indices,
+ 			unsigned long first_index, unsigned int max_items);
++#ifndef CONFIG_PREEMPT_RT_FULL
+ int radix_tree_preload(gfp_t gfp_mask);
+ int radix_tree_maybe_preload(gfp_t gfp_mask);
++#else
++static inline int radix_tree_preload(gfp_t gm) { return 0; }
++static inline int radix_tree_maybe_preload(gfp_t gfp_mask) { return 0; }
++#endif
+ void radix_tree_init(void);
+ void *radix_tree_tag_set(struct radix_tree_root *root,
+ 			unsigned long index, unsigned int tag);
+@@ -303,7 +308,7 @@
+ 
+ static inline void radix_tree_preload_end(void)
+ {
+-	preempt_enable();
++	preempt_enable_nort();
+ }
+ 
+ /**
+diff -Nur linux-3.18.8.orig/include/linux/random.h linux-3.18.8/include/linux/random.h
+--- linux-3.18.8.orig/include/linux/random.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/random.h	2015-03-03 08:05:18.000000000 +0100
+@@ -11,7 +11,7 @@
+ extern void add_device_randomness(const void *, unsigned int);
+ extern void add_input_randomness(unsigned int type, unsigned int code,
+ 				 unsigned int value);
+-extern void add_interrupt_randomness(int irq, int irq_flags);
++extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip);
+ 
+ extern void get_random_bytes(void *buf, int nbytes);
+ extern void get_random_bytes_arch(void *buf, int nbytes);
+diff -Nur linux-3.18.8.orig/include/linux/rcupdate.h linux-3.18.8/include/linux/rcupdate.h
+--- linux-3.18.8.orig/include/linux/rcupdate.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/rcupdate.h	2015-03-03 08:05:18.000000000 +0100
+@@ -147,6 +147,9 @@
+ 
+ #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++#define call_rcu_bh	call_rcu
++#else
+ /**
+  * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
+  * @head: structure to be used for queueing the RCU updates.
+@@ -170,6 +173,7 @@
+  */
+ void call_rcu_bh(struct rcu_head *head,
+ 		 void (*func)(struct rcu_head *head));
++#endif
+ 
+ /**
+  * call_rcu_sched() - Queue an RCU for invocation after sched grace period.
+@@ -231,6 +235,11 @@
+  * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
+  */
+ #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
++#ifndef CONFIG_PREEMPT_RT_FULL
++#define sched_rcu_preempt_depth()	rcu_preempt_depth()
++#else
++static inline int sched_rcu_preempt_depth(void) { return 0; }
++#endif
+ 
+ #else /* #ifdef CONFIG_PREEMPT_RCU */
+ 
+@@ -254,6 +263,8 @@
+ 	return 0;
+ }
+ 
++#define sched_rcu_preempt_depth()	rcu_preempt_depth()
++
+ #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+ 
+ /* Internal to kernel */
+@@ -430,7 +441,14 @@
+ int debug_lockdep_rcu_enabled(void);
+ 
+ int rcu_read_lock_held(void);
++#ifdef CONFIG_PREEMPT_RT_FULL
++static inline int rcu_read_lock_bh_held(void)
++{
++	return rcu_read_lock_held();
++}
++#else
+ int rcu_read_lock_bh_held(void);
++#endif
+ 
+ /**
+  * rcu_read_lock_sched_held() - might we be in RCU-sched read-side critical section?
+@@ -955,10 +973,14 @@
+ static inline void rcu_read_lock_bh(void)
+ {
+ 	local_bh_disable();
++#ifdef CONFIG_PREEMPT_RT_FULL
++	rcu_read_lock();
++#else
+ 	__acquire(RCU_BH);
+ 	rcu_lock_acquire(&rcu_bh_lock_map);
+ 	rcu_lockdep_assert(rcu_is_watching(),
+ 			   "rcu_read_lock_bh() used illegally while idle");
++#endif
+ }
+ 
+ /*
+@@ -968,10 +990,14 @@
+  */
+ static inline void rcu_read_unlock_bh(void)
+ {
++#ifdef CONFIG_PREEMPT_RT_FULL
++	rcu_read_unlock();
++#else
+ 	rcu_lockdep_assert(rcu_is_watching(),
+ 			   "rcu_read_unlock_bh() used illegally while idle");
+ 	rcu_lock_release(&rcu_bh_lock_map);
+ 	__release(RCU_BH);
++#endif
+ 	local_bh_enable();
+ }
+ 
+diff -Nur linux-3.18.8.orig/include/linux/rcutree.h linux-3.18.8/include/linux/rcutree.h
+--- linux-3.18.8.orig/include/linux/rcutree.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/rcutree.h	2015-03-03 08:05:18.000000000 +0100
+@@ -46,7 +46,11 @@
+ 	rcu_note_context_switch(cpu);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define synchronize_rcu_bh	synchronize_rcu
++#else
+ void synchronize_rcu_bh(void);
++#endif
+ void synchronize_sched_expedited(void);
+ void synchronize_rcu_expedited(void);
+ 
+@@ -74,7 +78,11 @@
+ }
+ 
+ void rcu_barrier(void);
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define rcu_barrier_bh                rcu_barrier
++#else
+ void rcu_barrier_bh(void);
++#endif
+ void rcu_barrier_sched(void);
+ unsigned long get_state_synchronize_rcu(void);
+ void cond_synchronize_rcu(unsigned long oldstate);
+@@ -82,12 +90,10 @@
+ extern unsigned long rcutorture_testseq;
+ extern unsigned long rcutorture_vernum;
+ long rcu_batches_completed(void);
+-long rcu_batches_completed_bh(void);
+ long rcu_batches_completed_sched(void);
+ void show_rcu_gp_kthreads(void);
+ 
+ void rcu_force_quiescent_state(void);
+-void rcu_bh_force_quiescent_state(void);
+ void rcu_sched_force_quiescent_state(void);
+ 
+ void exit_rcu(void);
+@@ -97,4 +103,12 @@
+ 
+ bool rcu_is_watching(void);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++void rcu_bh_force_quiescent_state(void);
++long rcu_batches_completed_bh(void);
++#else
++# define rcu_bh_force_quiescent_state	rcu_force_quiescent_state
++# define rcu_batches_completed_bh	rcu_batches_completed
++#endif
++
+ #endif /* __LINUX_RCUTREE_H */
+diff -Nur linux-3.18.8.orig/include/linux/rtmutex.h linux-3.18.8/include/linux/rtmutex.h
+--- linux-3.18.8.orig/include/linux/rtmutex.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/rtmutex.h	2015-03-03 08:05:18.000000000 +0100
+@@ -14,10 +14,14 @@
+ 
+ #include <linux/linkage.h>
+ #include <linux/rbtree.h>
+-#include <linux/spinlock_types.h>
++#include <linux/spinlock_types_raw.h>
+ 
+ extern int max_lock_depth; /* for sysctl */
+ 
++#ifdef CONFIG_DEBUG_MUTEXES
++#include <linux/debug_locks.h>
++#endif
++
+ /**
+  * The rt_mutex structure
+  *
+@@ -31,8 +35,8 @@
+ 	struct rb_root          waiters;
+ 	struct rb_node          *waiters_leftmost;
+ 	struct task_struct	*owner;
+-#ifdef CONFIG_DEBUG_RT_MUTEXES
+ 	int			save_state;
++#ifdef CONFIG_DEBUG_RT_MUTEXES
+ 	const char 		*name, *file;
+ 	int			line;
+ 	void			*magic;
+@@ -55,22 +59,33 @@
+ # define rt_mutex_debug_check_no_locks_held(task)	do { } while (0)
+ #endif
+ 
++# define rt_mutex_init(mutex)					\
++	do {							\
++		raw_spin_lock_init(&(mutex)->wait_lock);	\
++		__rt_mutex_init(mutex, #mutex);			\
++	} while (0)
++
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+ # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+ 	, .name = #mutexname, .file = __FILE__, .line = __LINE__
+-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, __func__)
+  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+ #else
+ # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
+-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL)
+ # define rt_mutex_debug_task_free(t)			do { } while (0)
+ #endif
+ 
+-#define __RT_MUTEX_INITIALIZER(mutexname) \
+-	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
++#define __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
++	 .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
+ 	, .waiters = RB_ROOT \
+ 	, .owner = NULL \
+-	__DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
++	__DEBUG_RT_MUTEX_INITIALIZER(mutexname)
++
++#define __RT_MUTEX_INITIALIZER(mutexname) \
++	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname) }
++
++#define __RT_MUTEX_INITIALIZER_SAVE_STATE(mutexname) \
++	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname)    \
++	, .save_state = 1 }
+ 
+ #define DEFINE_RT_MUTEX(mutexname) \
+ 	struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
+@@ -91,6 +106,7 @@
+ 
+ extern void rt_mutex_lock(struct rt_mutex *lock);
+ extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
++extern int rt_mutex_lock_killable(struct rt_mutex *lock);
+ extern int rt_mutex_timed_lock(struct rt_mutex *lock,
+ 			       struct hrtimer_sleeper *timeout);
+ 
+diff -Nur linux-3.18.8.orig/include/linux/rwlock_rt.h linux-3.18.8/include/linux/rwlock_rt.h
+--- linux-3.18.8.orig/include/linux/rwlock_rt.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/rwlock_rt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,99 @@
++#ifndef __LINUX_RWLOCK_RT_H
++#define __LINUX_RWLOCK_RT_H
++
++#ifndef __LINUX_SPINLOCK_H
++#error Do not include directly. Use spinlock.h
++#endif
++
++#define rwlock_init(rwl)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	rt_mutex_init(&(rwl)->lock);			\
++	__rt_rwlock_init(rwl, #rwl, &__key);		\
++} while (0)
++
++extern void __lockfunc rt_write_lock(rwlock_t *rwlock);
++extern void __lockfunc rt_read_lock(rwlock_t *rwlock);
++extern int __lockfunc rt_write_trylock(rwlock_t *rwlock);
++extern int __lockfunc rt_write_trylock_irqsave(rwlock_t *trylock, unsigned long *flags);
++extern int __lockfunc rt_read_trylock(rwlock_t *rwlock);
++extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
++extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
++extern unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock);
++extern unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock);
++extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
++
++#define read_trylock(lock)	__cond_lock(lock, rt_read_trylock(lock))
++#define write_trylock(lock)	__cond_lock(lock, rt_write_trylock(lock))
++
++#define write_trylock_irqsave(lock, flags)	\
++	__cond_lock(lock, rt_write_trylock_irqsave(lock, &flags))
++
++#define read_lock_irqsave(lock, flags)			\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		flags = rt_read_lock_irqsave(lock);	\
++	} while (0)
++
++#define write_lock_irqsave(lock, flags)			\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		flags = rt_write_lock_irqsave(lock);	\
++	} while (0)
++
++#define read_lock(lock)		rt_read_lock(lock)
++
++#define read_lock_bh(lock)				\
++	do {						\
++		local_bh_disable();			\
++		rt_read_lock(lock);			\
++	} while (0)
++
++#define read_lock_irq(lock)	read_lock(lock)
++
++#define write_lock(lock)	rt_write_lock(lock)
++
++#define write_lock_bh(lock)				\
++	do {						\
++		local_bh_disable();			\
++		rt_write_lock(lock);			\
++	} while (0)
++
++#define write_lock_irq(lock)	write_lock(lock)
++
++#define read_unlock(lock)	rt_read_unlock(lock)
++
++#define read_unlock_bh(lock)				\
++	do {						\
++		rt_read_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define read_unlock_irq(lock)	read_unlock(lock)
++
++#define write_unlock(lock)	rt_write_unlock(lock)
++
++#define write_unlock_bh(lock)				\
++	do {						\
++		rt_write_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define write_unlock_irq(lock)	write_unlock(lock)
++
++#define read_unlock_irqrestore(lock, flags)		\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		rt_read_unlock(lock);			\
++	} while (0)
++
++#define write_unlock_irqrestore(lock, flags) \
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		rt_write_unlock(lock);			\
++	} while (0)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/rwlock_types.h linux-3.18.8/include/linux/rwlock_types.h
+--- linux-3.18.8.orig/include/linux/rwlock_types.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/rwlock_types.h	2015-03-03 08:05:18.000000000 +0100
+@@ -1,6 +1,10 @@
+ #ifndef __LINUX_RWLOCK_TYPES_H
+ #define __LINUX_RWLOCK_TYPES_H
+ 
++#if !defined(__LINUX_SPINLOCK_TYPES_H)
++# error "Do not include directly, include spinlock_types.h"
++#endif
++
+ /*
+  * include/linux/rwlock_types.h - generic rwlock type definitions
+  *				  and initializers
+@@ -43,6 +47,7 @@
+ 				RW_DEP_MAP_INIT(lockname) }
+ #endif
+ 
+-#define DEFINE_RWLOCK(x)	rwlock_t x = __RW_LOCK_UNLOCKED(x)
++#define DEFINE_RWLOCK(name) \
++	rwlock_t name __cacheline_aligned_in_smp = __RW_LOCK_UNLOCKED(name)
+ 
+ #endif /* __LINUX_RWLOCK_TYPES_H */
+diff -Nur linux-3.18.8.orig/include/linux/rwlock_types_rt.h linux-3.18.8/include/linux/rwlock_types_rt.h
+--- linux-3.18.8.orig/include/linux/rwlock_types_rt.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/rwlock_types_rt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,33 @@
++#ifndef __LINUX_RWLOCK_TYPES_RT_H
++#define __LINUX_RWLOCK_TYPES_RT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++/*
++ * rwlocks - rtmutex which allows single reader recursion
++ */
++typedef struct {
++	struct rt_mutex		lock;
++	int			read_depth;
++	unsigned int		break_lock;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++} rwlock_t;
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
++#else
++# define RW_DEP_MAP_INIT(lockname)
++#endif
++
++#define __RW_LOCK_UNLOCKED(name) \
++	{ .lock = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.lock),	\
++	  RW_DEP_MAP_INIT(name) }
++
++#define DEFINE_RWLOCK(name) \
++	rwlock_t name __cacheline_aligned_in_smp = __RW_LOCK_UNLOCKED(name)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/rwsem.h linux-3.18.8/include/linux/rwsem.h
+--- linux-3.18.8.orig/include/linux/rwsem.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/rwsem.h	2015-03-03 08:05:18.000000000 +0100
+@@ -18,6 +18,10 @@
+ #include <linux/osq_lock.h>
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++#include <linux/rwsem_rt.h>
++#else /* PREEMPT_RT_FULL */
++
+ struct rw_semaphore;
+ 
+ #ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
+@@ -177,4 +181,6 @@
+ # define up_read_non_owner(sem)			up_read(sem)
+ #endif
+ 
++#endif /* !PREEMPT_RT_FULL */
++
+ #endif /* _LINUX_RWSEM_H */
+diff -Nur linux-3.18.8.orig/include/linux/rwsem_rt.h linux-3.18.8/include/linux/rwsem_rt.h
+--- linux-3.18.8.orig/include/linux/rwsem_rt.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/rwsem_rt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,133 @@
++#ifndef _LINUX_RWSEM_RT_H
++#define _LINUX_RWSEM_RT_H
++
++#ifndef _LINUX_RWSEM_H
++#error "Include rwsem.h"
++#endif
++
++/*
++ * RW-semaphores are a spinlock plus a reader-depth count.
++ *
++ * Note that the semantics are different from the usual
++ * Linux rw-sems, in PREEMPT_RT mode we do not allow
++ * multiple readers to hold the lock at once, we only allow
++ * a read-lock owner to read-lock recursively. This is
++ * better for latency, makes the implementation inherently
++ * fair and makes it simpler as well.
++ */
++
++#include <linux/rtmutex.h>
++
++struct rw_semaphore {
++	struct rt_mutex		lock;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++};
++
++#define __RWSEM_INITIALIZER(name) \
++	{ .lock = __RT_MUTEX_INITIALIZER(name.lock), \
++	  RW_DEP_MAP_INIT(name) }
++
++#define DECLARE_RWSEM(lockname) \
++	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
++
++extern void  __rt_rwsem_init(struct rw_semaphore *rwsem, const char *name,
++				     struct lock_class_key *key);
++
++#define __rt_init_rwsem(sem, name, key)			\
++	do {						\
++		rt_mutex_init(&(sem)->lock);		\
++		__rt_rwsem_init((sem), (name), (key));\
++	} while (0)
++
++#define __init_rwsem(sem, name, key) __rt_init_rwsem(sem, name, key)
++
++# define rt_init_rwsem(sem)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	__rt_init_rwsem((sem), #sem, &__key);		\
++} while (0)
++
++extern void  rt_down_write(struct rw_semaphore *rwsem);
++extern void rt_down_read_nested(struct rw_semaphore *rwsem, int subclass);
++extern void rt_down_write_nested(struct rw_semaphore *rwsem, int subclass);
++extern void rt_down_write_nested_lock(struct rw_semaphore *rwsem,
++		struct lockdep_map *nest);
++extern void  rt_down_read(struct rw_semaphore *rwsem);
++extern int  rt_down_write_trylock(struct rw_semaphore *rwsem);
++extern int  rt_down_read_trylock(struct rw_semaphore *rwsem);
++extern void  rt_up_read(struct rw_semaphore *rwsem);
++extern void  rt_up_write(struct rw_semaphore *rwsem);
++extern void  rt_downgrade_write(struct rw_semaphore *rwsem);
++
++#define init_rwsem(sem)		rt_init_rwsem(sem)
++#define rwsem_is_locked(s)	rt_mutex_is_locked(&(s)->lock)
++
++static inline int rwsem_is_contended(struct rw_semaphore *sem)
++{
++	/* rt_mutex_has_waiters() */
++	return !RB_EMPTY_ROOT(&sem->lock.waiters);
++}
++
++static inline void down_read(struct rw_semaphore *sem)
++{
++	rt_down_read(sem);
++}
++
++static inline int down_read_trylock(struct rw_semaphore *sem)
++{
++	return rt_down_read_trylock(sem);
++}
++
++static inline void down_write(struct rw_semaphore *sem)
++{
++	rt_down_write(sem);
++}
++
++static inline int down_write_trylock(struct rw_semaphore *sem)
++{
++	return rt_down_write_trylock(sem);
++}
++
++static inline void up_read(struct rw_semaphore *sem)
++{
++	rt_up_read(sem);
++}
++
++static inline void up_write(struct rw_semaphore *sem)
++{
++	rt_up_write(sem);
++}
++
++static inline void downgrade_write(struct rw_semaphore *sem)
++{
++	rt_downgrade_write(sem);
++}
++
++static inline void down_read_nested(struct rw_semaphore *sem, int subclass)
++{
++	return rt_down_read_nested(sem, subclass);
++}
++
++static inline void down_write_nested(struct rw_semaphore *sem, int subclass)
++{
++	rt_down_write_nested(sem, subclass);
++}
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++static inline void down_write_nest_lock(struct rw_semaphore *sem,
++		struct rw_semaphore *nest_lock)
++{
++	rt_down_write_nested_lock(sem, &nest_lock->dep_map);
++}
++
++#else
++
++static inline void down_write_nest_lock(struct rw_semaphore *sem,
++		struct rw_semaphore *nest_lock)
++{
++	rt_down_write_nested_lock(sem, NULL);
++}
++#endif
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/sched.h linux-3.18.8/include/linux/sched.h
+--- linux-3.18.8.orig/include/linux/sched.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/sched.h	2015-03-03 08:05:18.000000000 +0100
+@@ -26,6 +26,7 @@
+ #include <linux/nodemask.h>
+ #include <linux/mm_types.h>
+ #include <linux/preempt_mask.h>
++#include <asm/kmap_types.h>
+ 
+ #include <asm/page.h>
+ #include <asm/ptrace.h>
+@@ -56,6 +57,7 @@
+ #include <linux/cred.h>
+ #include <linux/llist.h>
+ #include <linux/uidgid.h>
++#include <linux/hardirq.h>
+ #include <linux/gfp.h>
+ #include <linux/magic.h>
+ 
+@@ -235,10 +237,7 @@
+ 				 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
+ 				 __TASK_TRACED | EXIT_ZOMBIE | EXIT_DEAD)
+ 
+-#define task_is_traced(task)	((task->state & __TASK_TRACED) != 0)
+ #define task_is_stopped(task)	((task->state & __TASK_STOPPED) != 0)
+-#define task_is_stopped_or_traced(task)	\
+-			((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
+ #define task_contributes_to_load(task)	\
+ 				((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
+ 				 (task->flags & PF_FROZEN) == 0)
+@@ -1234,6 +1233,7 @@
+ 
+ struct task_struct {
+ 	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
++	volatile long saved_state;	/* saved state for "spinlock sleepers" */
+ 	void *stack;
+ 	atomic_t usage;
+ 	unsigned int flags;	/* per process flags, defined below */
+@@ -1270,6 +1270,12 @@
+ #endif
+ 
+ 	unsigned int policy;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	int migrate_disable;
++# ifdef CONFIG_SCHED_DEBUG
++	int migrate_disable_atomic;
++# endif
++#endif
+ 	int nr_cpus_allowed;
+ 	cpumask_t cpus_allowed;
+ 
+@@ -1371,7 +1377,8 @@
+ 	struct cputime prev_cputime;
+ #endif
+ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+-	seqlock_t vtime_seqlock;
++	raw_spinlock_t vtime_lock;
++	seqcount_t vtime_seq;
+ 	unsigned long long vtime_snap;
+ 	enum {
+ 		VTIME_SLEEPING = 0,
+@@ -1387,6 +1394,9 @@
+ 
+ 	struct task_cputime cputime_expires;
+ 	struct list_head cpu_timers[3];
++#ifdef CONFIG_PREEMPT_RT_BASE
++	struct task_struct *posix_timer_list;
++#endif
+ 
+ /* process credentials */
+ 	const struct cred __rcu *real_cred; /* objective and real subjective task
+@@ -1419,10 +1429,15 @@
+ /* signal handlers */
+ 	struct signal_struct *signal;
+ 	struct sighand_struct *sighand;
++	struct sigqueue *sigqueue_cache;
+ 
+ 	sigset_t blocked, real_blocked;
+ 	sigset_t saved_sigmask;	/* restored if set_restore_sigmask() was used */
+ 	struct sigpending pending;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	/* TODO: move me into ->restart_block ? */
++	struct siginfo forced_info;
++#endif
+ 
+ 	unsigned long sas_ss_sp;
+ 	size_t sas_ss_size;
+@@ -1460,6 +1475,9 @@
+ 	/* mutex deadlock detection */
+ 	struct mutex_waiter *blocked_on;
+ #endif
++#ifdef CONFIG_PREEMPT_RT_FULL
++	int pagefault_disabled;
++#endif
+ #ifdef CONFIG_TRACE_IRQFLAGS
+ 	unsigned int irq_events;
+ 	unsigned long hardirq_enable_ip;
+@@ -1644,6 +1662,12 @@
+ 	unsigned long trace;
+ 	/* bitmask and counter of trace recursion */
+ 	unsigned long trace_recursion;
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++	u64 preempt_timestamp_hist;
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++	long timer_offset;
++#endif
++#endif
+ #endif /* CONFIG_TRACING */
+ #ifdef CONFIG_MEMCG /* memcg uses this to do batch job */
+ 	unsigned int memcg_kmem_skip_account;
+@@ -1661,11 +1685,19 @@
+ 	unsigned int	sequential_io;
+ 	unsigned int	sequential_io_avg;
+ #endif
++#ifdef CONFIG_PREEMPT_RT_BASE
++	struct rcu_head put_rcu;
++	int softirq_nestcnt;
++	unsigned int softirqs_raised;
++#endif
++#ifdef CONFIG_PREEMPT_RT_FULL
++# if defined CONFIG_HIGHMEM || defined CONFIG_X86_32
++	int kmap_idx;
++	pte_t kmap_pte[KM_TYPE_NR];
++# endif
++#endif
+ };
+ 
+-/* Future-safe accessor for struct task_struct's cpus_allowed. */
+-#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
+-
+ #define TNF_MIGRATED	0x01
+ #define TNF_NO_GROUP	0x02
+ #define TNF_SHARED	0x04
+@@ -1700,6 +1732,17 @@
+ }
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++static inline bool cur_pf_disabled(void) { return current->pagefault_disabled; }
++#else
++static inline bool cur_pf_disabled(void) { return false; }
++#endif
++
++static inline bool pagefault_disabled(void)
++{
++	return in_atomic() || cur_pf_disabled();
++}
++
+ static inline struct pid *task_pid(struct task_struct *task)
+ {
+ 	return task->pids[PIDTYPE_PID].pid;
+@@ -1853,6 +1896,15 @@
+ extern void free_task(struct task_struct *tsk);
+ #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++extern void __put_task_struct_cb(struct rcu_head *rhp);
++
++static inline void put_task_struct(struct task_struct *t)
++{
++	if (atomic_dec_and_test(&t->usage))
++		call_rcu(&t->put_rcu, __put_task_struct_cb);
++}
++#else
+ extern void __put_task_struct(struct task_struct *t);
+ 
+ static inline void put_task_struct(struct task_struct *t)
+@@ -1860,6 +1912,7 @@
+ 	if (atomic_dec_and_test(&t->usage))
+ 		__put_task_struct(t);
+ }
++#endif
+ 
+ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+ extern void task_cputime(struct task_struct *t,
+@@ -1898,6 +1951,7 @@
+ /*
+  * Per process flags
+  */
++#define PF_IN_SOFTIRQ	0x00000001	/* Task is serving softirq */
+ #define PF_EXITING	0x00000004	/* getting shut down */
+ #define PF_EXITPIDONE	0x00000008	/* pi exit done on shut down */
+ #define PF_VCPU		0x00000010	/* I'm a virtual CPU */
+@@ -2058,6 +2112,10 @@
+ 
+ extern int set_cpus_allowed_ptr(struct task_struct *p,
+ 				const struct cpumask *new_mask);
++int migrate_me(void);
++void tell_sched_cpu_down_begin(int cpu);
++void tell_sched_cpu_down_done(int cpu);
++
+ #else
+ static inline void do_set_cpus_allowed(struct task_struct *p,
+ 				      const struct cpumask *new_mask)
+@@ -2070,6 +2128,9 @@
+ 		return -EINVAL;
+ 	return 0;
+ }
++static inline int migrate_me(void) { return 0; }
++static inline void tell_sched_cpu_down_begin(int cpu) { }
++static inline void tell_sched_cpu_down_done(int cpu) { }
+ #endif
+ 
+ #ifdef CONFIG_NO_HZ_COMMON
+@@ -2290,6 +2351,7 @@
+ 
+ extern int wake_up_state(struct task_struct *tsk, unsigned int state);
+ extern int wake_up_process(struct task_struct *tsk);
++extern int wake_up_lock_sleeper(struct task_struct * tsk);
+ extern void wake_up_new_task(struct task_struct *tsk);
+ #ifdef CONFIG_SMP
+  extern void kick_process(struct task_struct *tsk);
+@@ -2406,12 +2468,24 @@
+ 
+ /* mmdrop drops the mm and the page tables */
+ extern void __mmdrop(struct mm_struct *);
++
+ static inline void mmdrop(struct mm_struct * mm)
+ {
+ 	if (unlikely(atomic_dec_and_test(&mm->mm_count)))
+ 		__mmdrop(mm);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++extern void __mmdrop_delayed(struct rcu_head *rhp);
++static inline void mmdrop_delayed(struct mm_struct *mm)
++{
++	if (atomic_dec_and_test(&mm->mm_count))
++		call_rcu(&mm->delayed_drop, __mmdrop_delayed);
++}
++#else
++# define mmdrop_delayed(mm)	mmdrop(mm)
++#endif
++
+ /* mmput gets rid of the mappings and all user-space */
+ extern void mmput(struct mm_struct *);
+ /* Grab a reference to a task's mm, if it is not already going away */
+@@ -2719,6 +2793,43 @@
+ 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
+ }
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++static inline void set_tsk_need_resched_lazy(struct task_struct *tsk)
++{
++	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
++}
++
++static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk)
++{
++	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
++}
++
++static inline int test_tsk_need_resched_lazy(struct task_struct *tsk)
++{
++	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY));
++}
++
++static inline int need_resched_lazy(void)
++{
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++}
++
++static inline int need_resched_now(void)
++{
++	return test_thread_flag(TIF_NEED_RESCHED);
++}
++
++#else
++static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) { }
++static inline int need_resched_lazy(void) { return 0; }
++
++static inline int need_resched_now(void)
++{
++	return test_thread_flag(TIF_NEED_RESCHED);
++}
++
++#endif
++
+ static inline int restart_syscall(void)
+ {
+ 	set_tsk_thread_flag(current, TIF_SIGPENDING);
+@@ -2750,6 +2861,51 @@
+ 	return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p);
+ }
+ 
++static inline bool __task_is_stopped_or_traced(struct task_struct *task)
++{
++	if (task->state & (__TASK_STOPPED | __TASK_TRACED))
++		return true;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (task->saved_state & (__TASK_STOPPED | __TASK_TRACED))
++		return true;
++#endif
++	return false;
++}
++
++static inline bool task_is_stopped_or_traced(struct task_struct *task)
++{
++	bool traced_stopped;
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&task->pi_lock, flags);
++	traced_stopped = __task_is_stopped_or_traced(task);
++	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
++#else
++	traced_stopped = __task_is_stopped_or_traced(task);
++#endif
++	return traced_stopped;
++}
++
++static inline bool task_is_traced(struct task_struct *task)
++{
++	bool traced = false;
++
++	if (task->state & __TASK_TRACED)
++		return true;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	/* in case the task is sleeping on tasklist_lock */
++	raw_spin_lock_irq(&task->pi_lock);
++	if (task->state & __TASK_TRACED)
++		traced = true;
++	else if (task->saved_state & __TASK_TRACED)
++		traced = true;
++	raw_spin_unlock_irq(&task->pi_lock);
++#endif
++	return traced;
++}
++
+ /*
+  * cond_resched() and cond_resched_lock(): latency reduction via
+  * explicit rescheduling in places that are safe. The return
+@@ -2766,7 +2922,7 @@
+ 
+ extern int __cond_resched_lock(spinlock_t *lock);
+ 
+-#ifdef CONFIG_PREEMPT_COUNT
++#if defined(CONFIG_PREEMPT_COUNT) && !defined(CONFIG_PREEMPT_RT_FULL)
+ #define PREEMPT_LOCK_OFFSET	PREEMPT_OFFSET
+ #else
+ #define PREEMPT_LOCK_OFFSET	0
+@@ -2777,12 +2933,16 @@
+ 	__cond_resched_lock(lock);				\
+ })
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ extern int __cond_resched_softirq(void);
+ 
+ #define cond_resched_softirq() ({					\
+ 	__might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET);	\
+ 	__cond_resched_softirq();					\
+ })
++#else
++# define cond_resched_softirq()		cond_resched()
++#endif
+ 
+ static inline void cond_resched_rcu(void)
+ {
+@@ -2949,6 +3109,26 @@
+ 
+ #endif /* CONFIG_SMP */
+ 
++static inline int __migrate_disabled(struct task_struct *p)
++{
++#ifdef CONFIG_PREEMPT_RT_FULL
++	return p->migrate_disable;
++#else
++	return 0;
++#endif
++}
++
++/* Future-safe accessor for struct task_struct's cpus_allowed. */
++static inline const struct cpumask *tsk_cpus_allowed(struct task_struct *p)
++{
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (p->migrate_disable)
++		return cpumask_of(task_cpu(p));
++#endif
++
++	return &p->cpus_allowed;
++}
++
+ extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
+ extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
+ 
+diff -Nur linux-3.18.8.orig/include/linux/seqlock.h linux-3.18.8/include/linux/seqlock.h
+--- linux-3.18.8.orig/include/linux/seqlock.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/seqlock.h	2015-03-03 08:05:18.000000000 +0100
+@@ -219,20 +219,30 @@
+ 	return __read_seqcount_retry(s, start);
+ }
+ 
+-
+-
+-static inline void raw_write_seqcount_begin(seqcount_t *s)
++static inline void __raw_write_seqcount_begin(seqcount_t *s)
+ {
+ 	s->sequence++;
+ 	smp_wmb();
+ }
+ 
+-static inline void raw_write_seqcount_end(seqcount_t *s)
++static inline void raw_write_seqcount_begin(seqcount_t *s)
++{
++	preempt_disable_rt();
++	__raw_write_seqcount_begin(s);
++}
++
++static inline void __raw_write_seqcount_end(seqcount_t *s)
+ {
+ 	smp_wmb();
+ 	s->sequence++;
+ }
+ 
++static inline void raw_write_seqcount_end(seqcount_t *s)
++{
++	__raw_write_seqcount_end(s);
++	preempt_enable_rt();
++}
++
+ /*
+  * raw_write_seqcount_latch - redirect readers to even/odd copy
+  * @s: pointer to seqcount_t
+@@ -305,10 +315,32 @@
+ /*
+  * Read side functions for starting and finalizing a read side section.
+  */
++#ifndef CONFIG_PREEMPT_RT_FULL
+ static inline unsigned read_seqbegin(const seqlock_t *sl)
+ {
+ 	return read_seqcount_begin(&sl->seqcount);
+ }
++#else
++/*
++ * Starvation safe read side for RT
++ */
++static inline unsigned read_seqbegin(seqlock_t *sl)
++{
++	unsigned ret;
++
++repeat:
++	ret = ACCESS_ONCE(sl->seqcount.sequence);
++	if (unlikely(ret & 1)) {
++		/*
++		 * Take the lock and let the writer proceed (i.e. evtl
++		 * boost it), otherwise we could loop here forever.
++		 */
++		spin_unlock_wait(&sl->lock);
++		goto repeat;
++	}
++	return ret;
++}
++#endif
+ 
+ static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start)
+ {
+@@ -323,36 +355,36 @@
+ static inline void write_seqlock(seqlock_t *sl)
+ {
+ 	spin_lock(&sl->lock);
+-	write_seqcount_begin(&sl->seqcount);
++	__raw_write_seqcount_begin(&sl->seqcount);
+ }
+ 
+ static inline void write_sequnlock(seqlock_t *sl)
+ {
+-	write_seqcount_end(&sl->seqcount);
++	__raw_write_seqcount_end(&sl->seqcount);
+ 	spin_unlock(&sl->lock);
+ }
+ 
+ static inline void write_seqlock_bh(seqlock_t *sl)
+ {
+ 	spin_lock_bh(&sl->lock);
+-	write_seqcount_begin(&sl->seqcount);
++	__raw_write_seqcount_begin(&sl->seqcount);
+ }
+ 
+ static inline void write_sequnlock_bh(seqlock_t *sl)
+ {
+-	write_seqcount_end(&sl->seqcount);
++	__raw_write_seqcount_end(&sl->seqcount);
+ 	spin_unlock_bh(&sl->lock);
+ }
+ 
+ static inline void write_seqlock_irq(seqlock_t *sl)
+ {
+ 	spin_lock_irq(&sl->lock);
+-	write_seqcount_begin(&sl->seqcount);
++	__raw_write_seqcount_begin(&sl->seqcount);
+ }
+ 
+ static inline void write_sequnlock_irq(seqlock_t *sl)
+ {
+-	write_seqcount_end(&sl->seqcount);
++	__raw_write_seqcount_end(&sl->seqcount);
+ 	spin_unlock_irq(&sl->lock);
+ }
+ 
+@@ -361,7 +393,7 @@
+ 	unsigned long flags;
+ 
+ 	spin_lock_irqsave(&sl->lock, flags);
+-	write_seqcount_begin(&sl->seqcount);
++	__raw_write_seqcount_begin(&sl->seqcount);
+ 	return flags;
+ }
+ 
+@@ -371,7 +403,7 @@
+ static inline void
+ write_sequnlock_irqrestore(seqlock_t *sl, unsigned long flags)
+ {
+-	write_seqcount_end(&sl->seqcount);
++	__raw_write_seqcount_end(&sl->seqcount);
+ 	spin_unlock_irqrestore(&sl->lock, flags);
+ }
+ 
+diff -Nur linux-3.18.8.orig/include/linux/signal.h linux-3.18.8/include/linux/signal.h
+--- linux-3.18.8.orig/include/linux/signal.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/signal.h	2015-03-03 08:05:18.000000000 +0100
+@@ -218,6 +218,7 @@
+ }
+ 
+ extern void flush_sigqueue(struct sigpending *queue);
++extern void flush_task_sigqueue(struct task_struct *tsk);
+ 
+ /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
+ static inline int valid_signal(unsigned long sig)
+diff -Nur linux-3.18.8.orig/include/linux/skbuff.h linux-3.18.8/include/linux/skbuff.h
+--- linux-3.18.8.orig/include/linux/skbuff.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/skbuff.h	2015-03-03 08:05:18.000000000 +0100
+@@ -172,6 +172,7 @@
+ 
+ 	__u32		qlen;
+ 	spinlock_t	lock;
++	raw_spinlock_t	raw_lock;
+ };
+ 
+ struct sk_buff;
+@@ -1327,6 +1328,12 @@
+ 	__skb_queue_head_init(list);
+ }
+ 
++static inline void skb_queue_head_init_raw(struct sk_buff_head *list)
++{
++	raw_spin_lock_init(&list->raw_lock);
++	__skb_queue_head_init(list);
++}
++
+ static inline void skb_queue_head_init_class(struct sk_buff_head *list,
+ 		struct lock_class_key *class)
+ {
+diff -Nur linux-3.18.8.orig/include/linux/smp.h linux-3.18.8/include/linux/smp.h
+--- linux-3.18.8.orig/include/linux/smp.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/smp.h	2015-03-03 08:05:18.000000000 +0100
+@@ -178,6 +178,9 @@
+ #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
+ #define put_cpu()		preempt_enable()
+ 
++#define get_cpu_light()		({ migrate_disable(); smp_processor_id(); })
++#define put_cpu_light()		migrate_enable()
++
+ /*
+  * Callback to arch code if there's nosmp or maxcpus=0 on the
+  * boot command line:
+diff -Nur linux-3.18.8.orig/include/linux/spinlock_api_smp.h linux-3.18.8/include/linux/spinlock_api_smp.h
+--- linux-3.18.8.orig/include/linux/spinlock_api_smp.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock_api_smp.h	2015-03-03 08:05:18.000000000 +0100
+@@ -187,6 +187,8 @@
+ 	return 0;
+ }
+ 
+-#include <linux/rwlock_api_smp.h>
++#ifndef CONFIG_PREEMPT_RT_FULL
++# include <linux/rwlock_api_smp.h>
++#endif
+ 
+ #endif /* __LINUX_SPINLOCK_API_SMP_H */
+diff -Nur linux-3.18.8.orig/include/linux/spinlock.h linux-3.18.8/include/linux/spinlock.h
+--- linux-3.18.8.orig/include/linux/spinlock.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock.h	2015-03-03 08:05:18.000000000 +0100
+@@ -278,7 +278,11 @@
+ #define raw_spin_can_lock(lock)	(!raw_spin_is_locked(lock))
+ 
+ /* Include rwlock functions */
+-#include <linux/rwlock.h>
++#ifdef CONFIG_PREEMPT_RT_FULL
++# include <linux/rwlock_rt.h>
++#else
++# include <linux/rwlock.h>
++#endif
+ 
+ /*
+  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
+@@ -289,6 +293,10 @@
+ # include <linux/spinlock_api_up.h>
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++# include <linux/spinlock_rt.h>
++#else /* PREEMPT_RT_FULL */
++
+ /*
+  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
+  */
+@@ -418,4 +426,6 @@
+ #define atomic_dec_and_lock(atomic, lock) \
+ 		__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
+ 
++#endif /* !PREEMPT_RT_FULL */
++
+ #endif /* __LINUX_SPINLOCK_H */
+diff -Nur linux-3.18.8.orig/include/linux/spinlock_rt.h linux-3.18.8/include/linux/spinlock_rt.h
+--- linux-3.18.8.orig/include/linux/spinlock_rt.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock_rt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,167 @@
++#ifndef __LINUX_SPINLOCK_RT_H
++#define __LINUX_SPINLOCK_RT_H
++
++#ifndef __LINUX_SPINLOCK_H
++#error Do not include directly. Use spinlock.h
++#endif
++
++#include <linux/bug.h>
++
++extern void
++__rt_spin_lock_init(spinlock_t *lock, char *name, struct lock_class_key *key);
++
++#define spin_lock_init(slock)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	rt_mutex_init(&(slock)->lock);			\
++	__rt_spin_lock_init(slock, #slock, &__key);	\
++} while (0)
++
++extern void __lockfunc rt_spin_lock(spinlock_t *lock);
++extern unsigned long __lockfunc rt_spin_lock_trace_flags(spinlock_t *lock);
++extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
++extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
++extern void __lockfunc rt_spin_unlock_after_trylock_in_irq(spinlock_t *lock);
++extern void __lockfunc rt_spin_unlock_wait(spinlock_t *lock);
++extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
++extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
++extern int __lockfunc rt_spin_trylock(spinlock_t *lock);
++extern int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock);
++
++/*
++ * lockdep-less calls, for derived types like rwlock:
++ * (for trylock they can use rt_mutex_trylock() directly.
++ */
++extern void __lockfunc __rt_spin_lock(struct rt_mutex *lock);
++extern void __lockfunc __rt_spin_unlock(struct rt_mutex *lock);
++extern int __lockfunc __rt_spin_trylock(struct rt_mutex *lock);
++
++#define spin_lock(lock)				\
++	do {					\
++		migrate_disable();		\
++		rt_spin_lock(lock);		\
++	} while (0)
++
++#define spin_lock_bh(lock)			\
++	do {					\
++		local_bh_disable();		\
++		migrate_disable();		\
++		rt_spin_lock(lock);		\
++	} while (0)
++
++#define spin_lock_irq(lock)		spin_lock(lock)
++
++#define spin_do_trylock(lock)		__cond_lock(lock, rt_spin_trylock(lock))
++
++#define spin_trylock(lock)			\
++({						\
++	int __locked;				\
++	migrate_disable();			\
++	__locked = spin_do_trylock(lock);	\
++	if (!__locked)				\
++		migrate_enable();		\
++	__locked;				\
++})
++
++#ifdef CONFIG_LOCKDEP
++# define spin_lock_nested(lock, subclass)		\
++	do {						\
++		migrate_disable();			\
++		rt_spin_lock_nested(lock, subclass);	\
++	} while (0)
++
++# define spin_lock_irqsave_nested(lock, flags, subclass) \
++	do {						 \
++		typecheck(unsigned long, flags);	 \
++		flags = 0;				 \
++		migrate_disable();			 \
++		rt_spin_lock_nested(lock, subclass);	 \
++	} while (0)
++#else
++# define spin_lock_nested(lock, subclass)	spin_lock(lock)
++
++# define spin_lock_irqsave_nested(lock, flags, subclass) \
++	do {						 \
++		typecheck(unsigned long, flags);	 \
++		flags = 0;				 \
++		spin_lock(lock);			 \
++	} while (0)
++#endif
++
++#define spin_lock_irqsave(lock, flags)			 \
++	do {						 \
++		typecheck(unsigned long, flags);	 \
++		flags = 0;				 \
++		spin_lock(lock);			 \
++	} while (0)
++
++static inline unsigned long spin_lock_trace_flags(spinlock_t *lock)
++{
++	unsigned long flags = 0;
++#ifdef CONFIG_TRACE_IRQFLAGS
++	flags = rt_spin_lock_trace_flags(lock);
++#else
++	spin_lock(lock); /* lock_local */
++#endif
++	return flags;
++}
++
++/* FIXME: we need rt_spin_lock_nest_lock */
++#define spin_lock_nest_lock(lock, nest_lock) spin_lock_nested(lock, 0)
++
++#define spin_unlock(lock)				\
++	do {						\
++		rt_spin_unlock(lock);			\
++		migrate_enable();			\
++	} while (0)
++
++#define spin_unlock_bh(lock)				\
++	do {						\
++		rt_spin_unlock(lock);			\
++		migrate_enable();			\
++		local_bh_enable();			\
++	} while (0)
++
++#define spin_unlock_irq(lock)		spin_unlock(lock)
++
++#define spin_unlock_irqrestore(lock, flags)		\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		spin_unlock(lock);			\
++	} while (0)
++
++#define spin_trylock_bh(lock)	__cond_lock(lock, rt_spin_trylock_bh(lock))
++#define spin_trylock_irq(lock)	spin_trylock(lock)
++
++#define spin_trylock_irqsave(lock, flags)	\
++	rt_spin_trylock_irqsave(lock, &(flags))
++
++#define spin_unlock_wait(lock)		rt_spin_unlock_wait(lock)
++
++#ifdef CONFIG_GENERIC_LOCKBREAK
++# define spin_is_contended(lock)	((lock)->break_lock)
++#else
++# define spin_is_contended(lock)	(((void)(lock), 0))
++#endif
++
++static inline int spin_can_lock(spinlock_t *lock)
++{
++	return !rt_mutex_is_locked(&lock->lock);
++}
++
++static inline int spin_is_locked(spinlock_t *lock)
++{
++	return rt_mutex_is_locked(&lock->lock);
++}
++
++static inline void assert_spin_locked(spinlock_t *lock)
++{
++	BUG_ON(!spin_is_locked(lock));
++}
++
++#define atomic_dec_and_lock(atomic, lock) \
++	atomic_dec_and_spin_lock(atomic, lock)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/spinlock_types.h linux-3.18.8/include/linux/spinlock_types.h
+--- linux-3.18.8.orig/include/linux/spinlock_types.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock_types.h	2015-03-03 08:05:18.000000000 +0100
+@@ -9,80 +9,15 @@
+  * Released under the General Public License (GPL).
+  */
+ 
+-#if defined(CONFIG_SMP)
+-# include <asm/spinlock_types.h>
+-#else
+-# include <linux/spinlock_types_up.h>
+-#endif
+-
+-#include <linux/lockdep.h>
+-
+-typedef struct raw_spinlock {
+-	arch_spinlock_t raw_lock;
+-#ifdef CONFIG_GENERIC_LOCKBREAK
+-	unsigned int break_lock;
+-#endif
+-#ifdef CONFIG_DEBUG_SPINLOCK
+-	unsigned int magic, owner_cpu;
+-	void *owner;
+-#endif
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-	struct lockdep_map dep_map;
+-#endif
+-} raw_spinlock_t;
+-
+-#define SPINLOCK_MAGIC		0xdead4ead
+-
+-#define SPINLOCK_OWNER_INIT	((void *)-1L)
+-
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-# define SPIN_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+-#else
+-# define SPIN_DEP_MAP_INIT(lockname)
+-#endif
++#include <linux/spinlock_types_raw.h>
+ 
+-#ifdef CONFIG_DEBUG_SPINLOCK
+-# define SPIN_DEBUG_INIT(lockname)		\
+-	.magic = SPINLOCK_MAGIC,		\
+-	.owner_cpu = -1,			\
+-	.owner = SPINLOCK_OWNER_INIT,
++#ifndef CONFIG_PREEMPT_RT_FULL
++# include <linux/spinlock_types_nort.h>
++# include <linux/rwlock_types.h>
+ #else
+-# define SPIN_DEBUG_INIT(lockname)
++# include <linux/rtmutex.h>
++# include <linux/spinlock_types_rt.h>
++# include <linux/rwlock_types_rt.h>
+ #endif
+ 
+-#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
+-	{					\
+-	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
+-	SPIN_DEBUG_INIT(lockname)		\
+-	SPIN_DEP_MAP_INIT(lockname) }
+-
+-#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
+-	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
+-
+-#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
+-
+-typedef struct spinlock {
+-	union {
+-		struct raw_spinlock rlock;
+-
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
+-		struct {
+-			u8 __padding[LOCK_PADSIZE];
+-			struct lockdep_map dep_map;
+-		};
+-#endif
+-	};
+-} spinlock_t;
+-
+-#define __SPIN_LOCK_INITIALIZER(lockname) \
+-	{ { .rlock = __RAW_SPIN_LOCK_INITIALIZER(lockname) } }
+-
+-#define __SPIN_LOCK_UNLOCKED(lockname) \
+-	(spinlock_t ) __SPIN_LOCK_INITIALIZER(lockname)
+-
+-#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
+-
+-#include <linux/rwlock_types.h>
+-
+ #endif /* __LINUX_SPINLOCK_TYPES_H */
+diff -Nur linux-3.18.8.orig/include/linux/spinlock_types_nort.h linux-3.18.8/include/linux/spinlock_types_nort.h
+--- linux-3.18.8.orig/include/linux/spinlock_types_nort.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock_types_nort.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,33 @@
++#ifndef __LINUX_SPINLOCK_TYPES_NORT_H
++#define __LINUX_SPINLOCK_TYPES_NORT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++/*
++ * The non RT version maps spinlocks to raw_spinlocks
++ */
++typedef struct spinlock {
++	union {
++		struct raw_spinlock rlock;
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
++		struct {
++			u8 __padding[LOCK_PADSIZE];
++			struct lockdep_map dep_map;
++		};
++#endif
++	};
++} spinlock_t;
++
++#define __SPIN_LOCK_INITIALIZER(lockname) \
++	{ { .rlock = __RAW_SPIN_LOCK_INITIALIZER(lockname) } }
++
++#define __SPIN_LOCK_UNLOCKED(lockname) \
++	(spinlock_t ) __SPIN_LOCK_INITIALIZER(lockname)
++
++#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/spinlock_types_raw.h linux-3.18.8/include/linux/spinlock_types_raw.h
+--- linux-3.18.8.orig/include/linux/spinlock_types_raw.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock_types_raw.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,56 @@
++#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
++#define __LINUX_SPINLOCK_TYPES_RAW_H
++
++#if defined(CONFIG_SMP)
++# include <asm/spinlock_types.h>
++#else
++# include <linux/spinlock_types_up.h>
++#endif
++
++#include <linux/lockdep.h>
++
++typedef struct raw_spinlock {
++	arch_spinlock_t raw_lock;
++#ifdef CONFIG_GENERIC_LOCKBREAK
++	unsigned int break_lock;
++#endif
++#ifdef CONFIG_DEBUG_SPINLOCK
++	unsigned int magic, owner_cpu;
++	void *owner;
++#endif
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map dep_map;
++#endif
++} raw_spinlock_t;
++
++#define SPINLOCK_MAGIC		0xdead4ead
++
++#define SPINLOCK_OWNER_INIT	((void *)-1L)
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define SPIN_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
++#else
++# define SPIN_DEP_MAP_INIT(lockname)
++#endif
++
++#ifdef CONFIG_DEBUG_SPINLOCK
++# define SPIN_DEBUG_INIT(lockname)		\
++	.magic = SPINLOCK_MAGIC,		\
++	.owner_cpu = -1,			\
++	.owner = SPINLOCK_OWNER_INIT,
++#else
++# define SPIN_DEBUG_INIT(lockname)
++#endif
++
++#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
++	{					\
++	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
++	SPIN_DEBUG_INIT(lockname)		\
++	SPIN_DEP_MAP_INIT(lockname) }
++
++#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
++	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
++
++#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/spinlock_types_rt.h linux-3.18.8/include/linux/spinlock_types_rt.h
+--- linux-3.18.8.orig/include/linux/spinlock_types_rt.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/spinlock_types_rt.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,51 @@
++#ifndef __LINUX_SPINLOCK_TYPES_RT_H
++#define __LINUX_SPINLOCK_TYPES_RT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++#include <linux/cache.h>
++
++/*
++ * PREEMPT_RT: spinlocks - an RT mutex plus lock-break field:
++ */
++typedef struct spinlock {
++	struct rt_mutex		lock;
++	unsigned int		break_lock;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++} spinlock_t;
++
++#ifdef CONFIG_DEBUG_RT_MUTEXES
++# define __RT_SPIN_INITIALIZER(name) \
++	{ \
++	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
++	.save_state = 1, \
++	.file = __FILE__, \
++	.line = __LINE__ , \
++	}
++#else
++# define __RT_SPIN_INITIALIZER(name) \
++	{								\
++	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock),		\
++	.save_state = 1, \
++	}
++#endif
++
++/*
++.wait_list = PLIST_HEAD_INIT_RAW((name).lock.wait_list, (name).lock.wait_lock)
++*/
++
++#define __SPIN_LOCK_UNLOCKED(name)			\
++	{ .lock = __RT_SPIN_INITIALIZER(name.lock),		\
++	  SPIN_DEP_MAP_INIT(name) }
++
++#define __DEFINE_SPINLOCK(name) \
++	spinlock_t name = __SPIN_LOCK_UNLOCKED(name)
++
++#define DEFINE_SPINLOCK(name) \
++	spinlock_t name __cacheline_aligned_in_smp = __SPIN_LOCK_UNLOCKED(name)
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/srcu.h linux-3.18.8/include/linux/srcu.h
+--- linux-3.18.8.orig/include/linux/srcu.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/srcu.h	2015-03-03 08:05:18.000000000 +0100
+@@ -84,10 +84,10 @@
+ 
+ void process_srcu(struct work_struct *work);
+ 
+-#define __SRCU_STRUCT_INIT(name)					\
++#define __SRCU_STRUCT_INIT(name, pcpu_name)				\
+ 	{								\
+ 		.completed = -300,					\
+-		.per_cpu_ref = &name##_srcu_array,			\
++		.per_cpu_ref = &pcpu_name,				\
+ 		.queue_lock = __SPIN_LOCK_UNLOCKED(name.queue_lock),	\
+ 		.running = false,					\
+ 		.batch_queue = RCU_BATCH_INIT(name.batch_queue),	\
+@@ -104,11 +104,12 @@
+  */
+ #define DEFINE_SRCU(name)						\
+ 	static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\
+-	struct srcu_struct name = __SRCU_STRUCT_INIT(name);
++	struct srcu_struct name = __SRCU_STRUCT_INIT(name, name##_srcu_array);
+ 
+ #define DEFINE_STATIC_SRCU(name)					\
+ 	static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\
+-	static struct srcu_struct name = __SRCU_STRUCT_INIT(name);
++	static struct srcu_struct name = __SRCU_STRUCT_INIT(\
++		name, name##_srcu_array);
+ 
+ /**
+  * call_srcu() - Queue a callback for invocation after an SRCU grace period
+diff -Nur linux-3.18.8.orig/include/linux/swap.h linux-3.18.8/include/linux/swap.h
+--- linux-3.18.8.orig/include/linux/swap.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/swap.h	2015-03-03 08:05:18.000000000 +0100
+@@ -11,6 +11,7 @@
+ #include <linux/fs.h>
+ #include <linux/atomic.h>
+ #include <linux/page-flags.h>
++#include <linux/locallock.h>
+ #include <asm/page.h>
+ 
+ struct notifier_block;
+@@ -260,7 +261,8 @@
+ void *workingset_eviction(struct address_space *mapping, struct page *page);
+ bool workingset_refault(void *shadow);
+ void workingset_activation(struct page *page);
+-extern struct list_lru workingset_shadow_nodes;
++extern struct list_lru __workingset_shadow_nodes;
++DECLARE_LOCAL_IRQ_LOCK(workingset_shadow_lock);
+ 
+ static inline unsigned int workingset_node_pages(struct radix_tree_node *node)
+ {
+diff -Nur linux-3.18.8.orig/include/linux/sysctl.h linux-3.18.8/include/linux/sysctl.h
+--- linux-3.18.8.orig/include/linux/sysctl.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/sysctl.h	2015-03-03 08:05:18.000000000 +0100
+@@ -25,6 +25,7 @@
+ #include <linux/rcupdate.h>
+ #include <linux/wait.h>
+ #include <linux/rbtree.h>
++#include <linux/atomic.h>
+ #include <uapi/linux/sysctl.h>
+ 
+ /* For the /proc/sys support */
+diff -Nur linux-3.18.8.orig/include/linux/thread_info.h linux-3.18.8/include/linux/thread_info.h
+--- linux-3.18.8.orig/include/linux/thread_info.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/thread_info.h	2015-03-03 08:05:18.000000000 +0100
+@@ -102,7 +102,17 @@
+ #define test_thread_flag(flag) \
+ 	test_ti_thread_flag(current_thread_info(), flag)
+ 
+-#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
++#ifdef CONFIG_PREEMPT_LAZY
++#define tif_need_resched()	(test_thread_flag(TIF_NEED_RESCHED) || \
++				 test_thread_flag(TIF_NEED_RESCHED_LAZY))
++#define tif_need_resched_now()	(test_thread_flag(TIF_NEED_RESCHED))
++#define tif_need_resched_lazy()	test_thread_flag(TIF_NEED_RESCHED_LAZY))
++
++#else
++#define tif_need_resched()	test_thread_flag(TIF_NEED_RESCHED)
++#define tif_need_resched_now()	test_thread_flag(TIF_NEED_RESCHED)
++#define tif_need_resched_lazy()	0
++#endif
+ 
+ #if defined TIF_RESTORE_SIGMASK && !defined HAVE_SET_RESTORE_SIGMASK
+ /*
+diff -Nur linux-3.18.8.orig/include/linux/timer.h linux-3.18.8/include/linux/timer.h
+--- linux-3.18.8.orig/include/linux/timer.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/timer.h	2015-03-03 08:05:18.000000000 +0100
+@@ -241,7 +241,7 @@
+ 
+ extern int try_to_del_timer_sync(struct timer_list *timer);
+ 
+-#ifdef CONFIG_SMP
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
+   extern int del_timer_sync(struct timer_list *timer);
+ #else
+ # define del_timer_sync(t)		del_timer(t)
+diff -Nur linux-3.18.8.orig/include/linux/uaccess.h linux-3.18.8/include/linux/uaccess.h
+--- linux-3.18.8.orig/include/linux/uaccess.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/uaccess.h	2015-03-03 08:05:18.000000000 +0100
+@@ -6,14 +6,9 @@
+ 
+ /*
+  * These routines enable/disable the pagefault handler in that
+- * it will not take any locks and go straight to the fixup table.
+- *
+- * They have great resemblance to the preempt_disable/enable calls
+- * and in fact they are identical; this is because currently there is
+- * no other way to make the pagefault handlers do this. So we do
+- * disable preemption but we don't necessarily care about that.
++ * it will not take any MM locks and go straight to the fixup table.
+  */
+-static inline void pagefault_disable(void)
++static inline void raw_pagefault_disable(void)
+ {
+ 	preempt_count_inc();
+ 	/*
+@@ -23,7 +18,7 @@
+ 	barrier();
+ }
+ 
+-static inline void pagefault_enable(void)
++static inline void raw_pagefault_enable(void)
+ {
+ #ifndef CONFIG_PREEMPT
+ 	/*
+@@ -37,6 +32,21 @@
+ #endif
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++static inline void pagefault_disable(void)
++{
++	raw_pagefault_disable();
++}
++
++static inline void pagefault_enable(void)
++{
++	raw_pagefault_enable();
++}
++#else
++extern void pagefault_disable(void);
++extern void pagefault_enable(void);
++#endif
++
+ #ifndef ARCH_HAS_NOCACHE_UACCESS
+ 
+ static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
+@@ -76,9 +86,9 @@
+ 		mm_segment_t old_fs = get_fs();		\
+ 							\
+ 		set_fs(KERNEL_DS);			\
+-		pagefault_disable();			\
++		raw_pagefault_disable();		\
+ 		ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval));		\
+-		pagefault_enable();			\
++		raw_pagefault_enable();			\
+ 		set_fs(old_fs);				\
+ 		ret;					\
+ 	})
+diff -Nur linux-3.18.8.orig/include/linux/uprobes.h linux-3.18.8/include/linux/uprobes.h
+--- linux-3.18.8.orig/include/linux/uprobes.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/uprobes.h	2015-03-03 08:05:18.000000000 +0100
+@@ -27,6 +27,7 @@
+ #include <linux/errno.h>
+ #include <linux/rbtree.h>
+ #include <linux/types.h>
++#include <linux/wait.h>
+ 
+ struct vm_area_struct;
+ struct mm_struct;
+diff -Nur linux-3.18.8.orig/include/linux/vmstat.h linux-3.18.8/include/linux/vmstat.h
+--- linux-3.18.8.orig/include/linux/vmstat.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/vmstat.h	2015-03-03 08:05:18.000000000 +0100
+@@ -33,7 +33,9 @@
+  */
+ static inline void __count_vm_event(enum vm_event_item item)
+ {
++	preempt_disable_rt();
+ 	raw_cpu_inc(vm_event_states.event[item]);
++	preempt_enable_rt();
+ }
+ 
+ static inline void count_vm_event(enum vm_event_item item)
+@@ -43,7 +45,9 @@
+ 
+ static inline void __count_vm_events(enum vm_event_item item, long delta)
+ {
++	preempt_disable_rt();
+ 	raw_cpu_add(vm_event_states.event[item], delta);
++	preempt_enable_rt();
+ }
+ 
+ static inline void count_vm_events(enum vm_event_item item, long delta)
+diff -Nur linux-3.18.8.orig/include/linux/wait.h linux-3.18.8/include/linux/wait.h
+--- linux-3.18.8.orig/include/linux/wait.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/linux/wait.h	2015-03-03 08:05:18.000000000 +0100
+@@ -8,6 +8,7 @@
+ #include <linux/spinlock.h>
+ #include <asm/current.h>
+ #include <uapi/linux/wait.h>
++#include <linux/atomic.h>
+ 
+ typedef struct __wait_queue wait_queue_t;
+ typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, void *key);
+diff -Nur linux-3.18.8.orig/include/linux/wait-simple.h linux-3.18.8/include/linux/wait-simple.h
+--- linux-3.18.8.orig/include/linux/wait-simple.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/wait-simple.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,207 @@
++#ifndef _LINUX_WAIT_SIMPLE_H
++#define _LINUX_WAIT_SIMPLE_H
++
++#include <linux/spinlock.h>
++#include <linux/list.h>
++
++#include <asm/current.h>
++
++struct swaiter {
++	struct task_struct	*task;
++	struct list_head	node;
++};
++
++#define DEFINE_SWAITER(name)					\
++	struct swaiter name = {					\
++		.task	= current,				\
++		.node	= LIST_HEAD_INIT((name).node),		\
++	}
++
++struct swait_head {
++	raw_spinlock_t		lock;
++	struct list_head	list;
++};
++
++#define SWAIT_HEAD_INITIALIZER(name) {				\
++		.lock	= __RAW_SPIN_LOCK_UNLOCKED(name.lock),	\
++		.list	= LIST_HEAD_INIT((name).list),		\
++	}
++
++#define DEFINE_SWAIT_HEAD(name)					\
++	struct swait_head name = SWAIT_HEAD_INITIALIZER(name)
++
++extern void __init_swait_head(struct swait_head *h, struct lock_class_key *key);
++
++#define init_swait_head(swh)					\
++	do {							\
++		static struct lock_class_key __key;		\
++								\
++		__init_swait_head((swh), &__key);		\
++	} while (0)
++
++/*
++ * Waiter functions
++ */
++extern void swait_prepare_locked(struct swait_head *head, struct swaiter *w);
++extern void swait_prepare(struct swait_head *head, struct swaiter *w, int state);
++extern void swait_finish_locked(struct swait_head *head, struct swaiter *w);
++extern void swait_finish(struct swait_head *head, struct swaiter *w);
++
++/* Check whether a head has waiters enqueued */
++static inline bool swaitqueue_active(struct swait_head *h)
++{
++	/* Make sure the condition is visible before checking list_empty() */
++	smp_mb();
++	return !list_empty(&h->list);
++}
++
++/*
++ * Wakeup functions
++ */
++extern unsigned int __swait_wake(struct swait_head *head, unsigned int state, unsigned int num);
++extern unsigned int __swait_wake_locked(struct swait_head *head, unsigned int state, unsigned int num);
++
++#define swait_wake(head)			__swait_wake(head, TASK_NORMAL, 1)
++#define swait_wake_interruptible(head)		__swait_wake(head, TASK_INTERRUPTIBLE, 1)
++#define swait_wake_all(head)			__swait_wake(head, TASK_NORMAL, 0)
++#define swait_wake_all_interruptible(head)	__swait_wake(head, TASK_INTERRUPTIBLE, 0)
++
++/*
++ * Event API
++ */
++#define __swait_event(wq, condition)					\
++do {									\
++	DEFINE_SWAITER(__wait);						\
++									\
++	for (;;) {							\
++		swait_prepare(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
++		if (condition)						\
++			break;						\
++		schedule();						\
++	}								\
++	swait_finish(&wq, &__wait);					\
++} while (0)
++
++/**
++ * swait_event - sleep until a condition gets true
++ * @wq: the waitqueue to wait on
++ * @condition: a C expression for the event to wait for
++ *
++ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
++ * @condition evaluates to true. The @condition is checked each time
++ * the waitqueue @wq is woken up.
++ *
++ * wake_up() has to be called after changing any variable that could
++ * change the result of the wait condition.
++ */
++#define swait_event(wq, condition)					\
++do {									\
++	if (condition)							\
++		break;							\
++	__swait_event(wq, condition);					\
++} while (0)
++
++#define __swait_event_interruptible(wq, condition, ret)			\
++do {									\
++	DEFINE_SWAITER(__wait);						\
++									\
++	for (;;) {							\
++		swait_prepare(&wq, &__wait, TASK_INTERRUPTIBLE);	\
++		if (condition)						\
++			break;						\
++		if (signal_pending(current)) {				\
++			ret = -ERESTARTSYS;				\
++			break;						\
++		}							\
++		schedule();						\
++	}								\
++	swait_finish(&wq, &__wait);					\
++} while (0)
++
++#define __swait_event_interruptible_timeout(wq, condition, ret)		\
++do {									\
++	DEFINE_SWAITER(__wait);						\
++									\
++	for (;;) {							\
++		swait_prepare(&wq, &__wait, TASK_INTERRUPTIBLE);	\
++		if (condition)						\
++			break;						\
++		if (signal_pending(current)) {				\
++			ret = -ERESTARTSYS;				\
++			break;						\
++		}							\
++		ret = schedule_timeout(ret);				\
++		if (!ret)						\
++			break;						\
++	}								\
++	swait_finish(&wq, &__wait);					\
++} while (0)
++
++/**
++ * swait_event_interruptible - sleep until a condition gets true
++ * @wq: the waitqueue to wait on
++ * @condition: a C expression for the event to wait for
++ *
++ * The process is put to sleep (TASK_INTERRUPTIBLE) until the
++ * @condition evaluates to true. The @condition is checked each time
++ * the waitqueue @wq is woken up.
++ *
++ * wake_up() has to be called after changing any variable that could
++ * change the result of the wait condition.
++ */
++#define swait_event_interruptible(wq, condition)			\
++({									\
++	int __ret = 0;							\
++	if (!(condition))						\
++		__swait_event_interruptible(wq, condition, __ret);	\
++	__ret;								\
++})
++
++#define swait_event_interruptible_timeout(wq, condition, timeout)	\
++({									\
++	int __ret = timeout;						\
++	if (!(condition))						\
++		__swait_event_interruptible_timeout(wq, condition, __ret);	\
++	__ret;								\
++})
++
++#define __swait_event_timeout(wq, condition, ret)			\
++do {									\
++	DEFINE_SWAITER(__wait);						\
++									\
++	for (;;) {							\
++		swait_prepare(&wq, &__wait, TASK_UNINTERRUPTIBLE);	\
++		if (condition)						\
++			break;						\
++		ret = schedule_timeout(ret);				\
++		if (!ret)						\
++			break;						\
++	}								\
++	swait_finish(&wq, &__wait);					\
++} while (0)
++
++/**
++ * swait_event_timeout - sleep until a condition gets true or a timeout elapses
++ * @wq: the waitqueue to wait on
++ * @condition: a C expression for the event to wait for
++ * @timeout: timeout, in jiffies
++ *
++ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
++ * @condition evaluates to true. The @condition is checked each time
++ * the waitqueue @wq is woken up.
++ *
++ * wake_up() has to be called after changing any variable that could
++ * change the result of the wait condition.
++ *
++ * The function returns 0 if the @timeout elapsed, and the remaining
++ * jiffies if the condition evaluated to true before the timeout elapsed.
++ */
++#define swait_event_timeout(wq, condition, timeout)			\
++({									\
++	long __ret = timeout;						\
++	if (!(condition))						\
++		__swait_event_timeout(wq, condition, __ret);		\
++	__ret;								\
++})
++
++#endif
+diff -Nur linux-3.18.8.orig/include/linux/work-simple.h linux-3.18.8/include/linux/work-simple.h
+--- linux-3.18.8.orig/include/linux/work-simple.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/linux/work-simple.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,24 @@
++#ifndef _LINUX_SWORK_H
++#define _LINUX_SWORK_H
++
++#include <linux/list.h>
++
++struct swork_event {
++	struct list_head item;
++	unsigned long flags;
++	void (*func)(struct swork_event *);
++};
++
++static inline void INIT_SWORK(struct swork_event *event,
++			      void (*func)(struct swork_event *))
++{
++	event->flags = 0;
++	event->func = func;
++}
++
++bool swork_queue(struct swork_event *sev);
++
++int swork_get(void);
++void swork_put(void);
++
++#endif /* _LINUX_SWORK_H */
+diff -Nur linux-3.18.8.orig/include/net/dst.h linux-3.18.8/include/net/dst.h
+--- linux-3.18.8.orig/include/net/dst.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/net/dst.h	2015-03-03 08:05:18.000000000 +0100
+@@ -403,7 +403,7 @@
+ static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
+ 				   struct sk_buff *skb)
+ {
+-	const struct hh_cache *hh;
++	struct hh_cache *hh;
+ 
+ 	if (dst->pending_confirm) {
+ 		unsigned long now = jiffies;
+diff -Nur linux-3.18.8.orig/include/net/neighbour.h linux-3.18.8/include/net/neighbour.h
+--- linux-3.18.8.orig/include/net/neighbour.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/net/neighbour.h	2015-03-03 08:05:18.000000000 +0100
+@@ -387,7 +387,7 @@
+ }
+ #endif
+ 
+-static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
++static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
+ {
+ 	unsigned int seq;
+ 	int hh_len;
+@@ -442,7 +442,7 @@
+ 
+ #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
+ 
+-static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
++static inline void neigh_ha_snapshot(char *dst, struct neighbour *n,
+ 				     const struct net_device *dev)
+ {
+ 	unsigned int seq;
+diff -Nur linux-3.18.8.orig/include/net/netns/ipv4.h linux-3.18.8/include/net/netns/ipv4.h
+--- linux-3.18.8.orig/include/net/netns/ipv4.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/include/net/netns/ipv4.h	2015-03-03 08:05:18.000000000 +0100
+@@ -67,6 +67,7 @@
+ 
+ 	int sysctl_icmp_echo_ignore_all;
+ 	int sysctl_icmp_echo_ignore_broadcasts;
++	int sysctl_icmp_echo_sysrq;
+ 	int sysctl_icmp_ignore_bogus_error_responses;
+ 	int sysctl_icmp_ratelimit;
+ 	int sysctl_icmp_ratemask;
+diff -Nur linux-3.18.8.orig/include/trace/events/hist.h linux-3.18.8/include/trace/events/hist.h
+--- linux-3.18.8.orig/include/trace/events/hist.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/trace/events/hist.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,72 @@
++#undef TRACE_SYSTEM
++#define TRACE_SYSTEM hist
++
++#if !defined(_TRACE_HIST_H) || defined(TRACE_HEADER_MULTI_READ)
++#define _TRACE_HIST_H
++
++#include "latency_hist.h"
++#include <linux/tracepoint.h>
++
++#if !defined(CONFIG_PREEMPT_OFF_HIST) && !defined(CONFIG_INTERRUPT_OFF_HIST)
++#define trace_preemptirqsoff_hist(a, b)
++#else
++TRACE_EVENT(preemptirqsoff_hist,
++
++	TP_PROTO(int reason, int starthist),
++
++	TP_ARGS(reason, starthist),
++
++	TP_STRUCT__entry(
++		__field(int,	reason)
++		__field(int,	starthist)
++	),
++
++	TP_fast_assign(
++		__entry->reason		= reason;
++		__entry->starthist	= starthist;
++	),
++
++	TP_printk("reason=%s starthist=%s", getaction(__entry->reason),
++		  __entry->starthist ? "start" : "stop")
++);
++#endif
++
++#ifndef CONFIG_MISSED_TIMER_OFFSETS_HIST
++#define trace_hrtimer_interrupt(a, b, c, d)
++#else
++TRACE_EVENT(hrtimer_interrupt,
++
++	TP_PROTO(int cpu, long long offset, struct task_struct *curr,
++		struct task_struct *task),
++
++	TP_ARGS(cpu, offset, curr, task),
++
++	TP_STRUCT__entry(
++		__field(int,		cpu)
++		__field(long long,	offset)
++		__array(char,		ccomm,	TASK_COMM_LEN)
++		__field(int,		cprio)
++		__array(char,		tcomm,	TASK_COMM_LEN)
++		__field(int,		tprio)
++	),
++
++	TP_fast_assign(
++		__entry->cpu	= cpu;
++		__entry->offset	= offset;
++		memcpy(__entry->ccomm, curr->comm, TASK_COMM_LEN);
++		__entry->cprio  = curr->prio;
++		memcpy(__entry->tcomm, task != NULL ? task->comm : "<none>",
++			task != NULL ? TASK_COMM_LEN : 7);
++		__entry->tprio  = task != NULL ? task->prio : -1;
++	),
++
++	TP_printk("cpu=%d offset=%lld curr=%s[%d] thread=%s[%d]",
++		__entry->cpu, __entry->offset, __entry->ccomm,
++		__entry->cprio, __entry->tcomm, __entry->tprio)
++);
++#endif
++
++#endif /* _TRACE_HIST_H */
++
++/* This part must be outside protection */
++#include <trace/define_trace.h>
+diff -Nur linux-3.18.8.orig/include/trace/events/latency_hist.h linux-3.18.8/include/trace/events/latency_hist.h
+--- linux-3.18.8.orig/include/trace/events/latency_hist.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/include/trace/events/latency_hist.h	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,29 @@
++#ifndef _LATENCY_HIST_H
++#define _LATENCY_HIST_H
++
++enum hist_action {
++	IRQS_ON,
++	PREEMPT_ON,
++	TRACE_STOP,
++	IRQS_OFF,
++	PREEMPT_OFF,
++	TRACE_START,
++};
++
++static char *actions[] = {
++	"IRQS_ON",
++	"PREEMPT_ON",
++	"TRACE_STOP",
++	"IRQS_OFF",
++	"PREEMPT_OFF",
++	"TRACE_START",
++};
++
++static inline char *getaction(int action)
++{
++	if (action >= 0 && action <= sizeof(actions)/sizeof(actions[0]))
++		return actions[action];
++	return "unknown";
++}
++
++#endif /* _LATENCY_HIST_H */
+diff -Nur linux-3.18.8.orig/init/Kconfig linux-3.18.8/init/Kconfig
+--- linux-3.18.8.orig/init/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/init/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -635,7 +635,7 @@
+ 
+ config RCU_FAST_NO_HZ
+ 	bool "Accelerate last non-dyntick-idle CPU's grace periods"
+-	depends on NO_HZ_COMMON && SMP
++	depends on NO_HZ_COMMON && SMP && !PREEMPT_RT_FULL
+ 	default n
+ 	help
+ 	  This option permits CPUs to enter dynticks-idle state even if
+@@ -662,7 +662,7 @@
+ config RCU_BOOST
+ 	bool "Enable RCU priority boosting"
+ 	depends on RT_MUTEXES && PREEMPT_RCU
+-	default n
++	default y if PREEMPT_RT_FULL
+ 	help
+ 	  This option boosts the priority of preempted RCU readers that
+ 	  block the current preemptible RCU grace period for too long.
+@@ -1106,6 +1106,7 @@
+ config RT_GROUP_SCHED
+ 	bool "Group scheduling for SCHED_RR/FIFO"
+ 	depends on CGROUP_SCHED
++	depends on !PREEMPT_RT_FULL
+ 	default n
+ 	help
+ 	  This feature lets you explicitly allocate real CPU bandwidth
+@@ -1677,6 +1678,7 @@
+ 
+ config SLAB
+ 	bool "SLAB"
++	depends on !PREEMPT_RT_FULL
+ 	help
+ 	  The regular slab allocator that is established and known to work
+ 	  well in all environments. It organizes cache hot objects in
+@@ -1695,6 +1697,7 @@
+ config SLOB
+ 	depends on EXPERT
+ 	bool "SLOB (Simple Allocator)"
++	depends on !PREEMPT_RT_FULL
+ 	help
+ 	   SLOB replaces the stock allocator with a drastically simpler
+ 	   allocator. SLOB is generally more space efficient but
+diff -Nur linux-3.18.8.orig/init/main.c linux-3.18.8/init/main.c
+--- linux-3.18.8.orig/init/main.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/init/main.c	2015-03-03 08:05:18.000000000 +0100
+@@ -533,6 +533,7 @@
+ 	setup_command_line(command_line);
+ 	setup_nr_cpu_ids();
+ 	setup_per_cpu_areas();
++	softirq_early_init();
+ 	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
+ 
+ 	build_all_zonelists(NULL, NULL);
+diff -Nur linux-3.18.8.orig/init/Makefile linux-3.18.8/init/Makefile
+--- linux-3.18.8.orig/init/Makefile	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/init/Makefile	2015-03-03 08:05:18.000000000 +0100
+@@ -33,4 +33,4 @@
+ include/generated/compile.h: FORCE
+ 	@$($(quiet)chk_compile.h)
+ 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
+-	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(KBUILD_CFLAGS)"
++	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CONFIG_PREEMPT_RT_FULL)" "$(CC) $(KBUILD_CFLAGS)"
+diff -Nur linux-3.18.8.orig/ipc/mqueue.c linux-3.18.8/ipc/mqueue.c
+--- linux-3.18.8.orig/ipc/mqueue.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/ipc/mqueue.c	2015-03-03 08:05:18.000000000 +0100
+@@ -923,12 +923,17 @@
+ 				  struct msg_msg *message,
+ 				  struct ext_wait_queue *receiver)
+ {
++	/*
++	 * Keep them in one critical section for PREEMPT_RT:
++	 */
++	preempt_disable_rt();
+ 	receiver->msg = message;
+ 	list_del(&receiver->list);
+ 	receiver->state = STATE_PENDING;
+ 	wake_up_process(receiver->task);
+ 	smp_wmb();
+ 	receiver->state = STATE_READY;
++	preempt_enable_rt();
+ }
+ 
+ /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
+@@ -942,13 +947,18 @@
+ 		wake_up_interruptible(&info->wait_q);
+ 		return;
+ 	}
+-	if (msg_insert(sender->msg, info))
+-		return;
+-	list_del(&sender->list);
+-	sender->state = STATE_PENDING;
+-	wake_up_process(sender->task);
+-	smp_wmb();
+-	sender->state = STATE_READY;
++	/*
++	 * Keep them in one critical section for PREEMPT_RT:
++	 */
++	preempt_disable_rt();
++	if (!msg_insert(sender->msg, info)) {
++		list_del(&sender->list);
++		sender->state = STATE_PENDING;
++		wake_up_process(sender->task);
++		smp_wmb();
++		sender->state = STATE_READY;
++	}
++	preempt_enable_rt();
+ }
+ 
+ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
+diff -Nur linux-3.18.8.orig/ipc/msg.c linux-3.18.8/ipc/msg.c
+--- linux-3.18.8.orig/ipc/msg.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/ipc/msg.c	2015-03-03 08:05:18.000000000 +0100
+@@ -188,6 +188,12 @@
+ 	struct msg_receiver *msr, *t;
+ 
+ 	list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
++		/*
++		 * Make sure that the wakeup doesnt preempt
++		 * this CPU prematurely. (on PREEMPT_RT)
++		 */
++		preempt_disable_rt();
++
+ 		msr->r_msg = NULL; /* initialize expunge ordering */
+ 		wake_up_process(msr->r_tsk);
+ 		/*
+@@ -198,6 +204,8 @@
+ 		 */
+ 		smp_mb();
+ 		msr->r_msg = ERR_PTR(res);
++
++		preempt_enable_rt();
+ 	}
+ }
+ 
+@@ -574,6 +582,11 @@
+ 		if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
+ 		    !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
+ 					       msr->r_msgtype, msr->r_mode)) {
++			/*
++			 * Make sure that the wakeup doesnt preempt
++			 * this CPU prematurely. (on PREEMPT_RT)
++			 */
++			preempt_disable_rt();
+ 
+ 			list_del(&msr->r_list);
+ 			if (msr->r_maxsize < msg->m_ts) {
+@@ -595,12 +608,13 @@
+ 				 */
+ 				smp_mb();
+ 				msr->r_msg = msg;
++				preempt_enable_rt();
+ 
+ 				return 1;
+ 			}
++			preempt_enable_rt();
+ 		}
+ 	}
+-
+ 	return 0;
+ }
+ 
+diff -Nur linux-3.18.8.orig/ipc/sem.c linux-3.18.8/ipc/sem.c
+--- linux-3.18.8.orig/ipc/sem.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/ipc/sem.c	2015-03-03 08:05:18.000000000 +0100
+@@ -673,6 +673,13 @@
+ static void wake_up_sem_queue_prepare(struct list_head *pt,
+ 				struct sem_queue *q, int error)
+ {
++#ifdef CONFIG_PREEMPT_RT_BASE
++	struct task_struct *p = q->sleeper;
++	get_task_struct(p);
++	q->status = error;
++	wake_up_process(p);
++	put_task_struct(p);
++#else
+ 	if (list_empty(pt)) {
+ 		/*
+ 		 * Hold preempt off so that we don't get preempted and have the
+@@ -684,6 +691,7 @@
+ 	q->pid = error;
+ 
+ 	list_add_tail(&q->list, pt);
++#endif
+ }
+ 
+ /**
+@@ -697,6 +705,7 @@
+  */
+ static void wake_up_sem_queue_do(struct list_head *pt)
+ {
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	struct sem_queue *q, *t;
+ 	int did_something;
+ 
+@@ -709,6 +718,7 @@
+ 	}
+ 	if (did_something)
+ 		preempt_enable();
++#endif
+ }
+ 
+ static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
+diff -Nur linux-3.18.8.orig/kernel/cgroup.c linux-3.18.8/kernel/cgroup.c
+--- linux-3.18.8.orig/kernel/cgroup.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/cgroup.c	2015-03-03 08:05:18.000000000 +0100
+@@ -4355,10 +4355,10 @@
+ 	queue_work(cgroup_destroy_wq, &css->destroy_work);
+ }
+ 
+-static void css_release_work_fn(struct work_struct *work)
++static void css_release_work_fn(struct swork_event *sev)
+ {
+ 	struct cgroup_subsys_state *css =
+-		container_of(work, struct cgroup_subsys_state, destroy_work);
++		container_of(sev, struct cgroup_subsys_state, destroy_swork);
+ 	struct cgroup_subsys *ss = css->ss;
+ 	struct cgroup *cgrp = css->cgroup;
+ 
+@@ -4395,8 +4395,8 @@
+ 	struct cgroup_subsys_state *css =
+ 		container_of(ref, struct cgroup_subsys_state, refcnt);
+ 
+-	INIT_WORK(&css->destroy_work, css_release_work_fn);
+-	queue_work(cgroup_destroy_wq, &css->destroy_work);
++	INIT_SWORK(&css->destroy_swork, css_release_work_fn);
++	swork_queue(&css->destroy_swork);
+ }
+ 
+ static void init_and_link_css(struct cgroup_subsys_state *css,
+@@ -4997,6 +4997,7 @@
+ 	 */
+ 	cgroup_destroy_wq = alloc_workqueue("cgroup_destroy", 0, 1);
+ 	BUG_ON(!cgroup_destroy_wq);
++	BUG_ON(swork_get());
+ 
+ 	/*
+ 	 * Used to destroy pidlists and separate to serve as flush domain.
+diff -Nur linux-3.18.8.orig/kernel/cpu.c linux-3.18.8/kernel/cpu.c
+--- linux-3.18.8.orig/kernel/cpu.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/cpu.c	2015-03-03 08:05:18.000000000 +0100
+@@ -86,6 +86,290 @@
+ #define cpuhp_lock_acquire()      lock_map_acquire(&cpu_hotplug.dep_map)
+ #define cpuhp_lock_release()      lock_map_release(&cpu_hotplug.dep_map)
+ 
++/**
++ * hotplug_pcp	- per cpu hotplug descriptor
++ * @unplug:	set when pin_current_cpu() needs to sync tasks
++ * @sync_tsk:	the task that waits for tasks to finish pinned sections
++ * @refcount:	counter of tasks in pinned sections
++ * @grab_lock:	set when the tasks entering pinned sections should wait
++ * @synced:	notifier for @sync_tsk to tell cpu_down it's finished
++ * @mutex:	the mutex to make tasks wait (used when @grab_lock is true)
++ * @mutex_init:	zero if the mutex hasn't been initialized yet.
++ *
++ * Although @unplug and @sync_tsk may point to the same task, the @unplug
++ * is used as a flag and still exists after @sync_tsk has exited and
++ * @sync_tsk set to NULL.
++ */
++struct hotplug_pcp {
++	struct task_struct *unplug;
++	struct task_struct *sync_tsk;
++	int refcount;
++	int grab_lock;
++	struct completion synced;
++	struct completion unplug_wait;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	/*
++	 * Note, on PREEMPT_RT, the hotplug lock must save the state of
++	 * the task, otherwise the mutex will cause the task to fail
++	 * to sleep when required. (Because it's called from migrate_disable())
++	 *
++	 * The spinlock_t on PREEMPT_RT is a mutex that saves the task's
++	 * state.
++	 */
++	spinlock_t lock;
++#else
++	struct mutex mutex;
++#endif
++	int mutex_init;
++};
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++# define hotplug_lock(hp) rt_spin_lock(&(hp)->lock)
++# define hotplug_unlock(hp) rt_spin_unlock(&(hp)->lock)
++#else
++# define hotplug_lock(hp) mutex_lock(&(hp)->mutex)
++# define hotplug_unlock(hp) mutex_unlock(&(hp)->mutex)
++#endif
++
++static DEFINE_PER_CPU(struct hotplug_pcp, hotplug_pcp);
++
++/**
++ * pin_current_cpu - Prevent the current cpu from being unplugged
++ *
++ * Lightweight version of get_online_cpus() to prevent cpu from being
++ * unplugged when code runs in a migration disabled region.
++ *
++ * Must be called with preemption disabled (preempt_count = 1)!
++ */
++void pin_current_cpu(void)
++{
++	struct hotplug_pcp *hp;
++	int force = 0;
++
++retry:
++	hp = &__get_cpu_var(hotplug_pcp);
++
++	if (!hp->unplug || hp->refcount || force || preempt_count() > 1 ||
++	    hp->unplug == current) {
++		hp->refcount++;
++		return;
++	}
++	if (hp->grab_lock) {
++		preempt_enable();
++		hotplug_lock(hp);
++		hotplug_unlock(hp);
++	} else {
++		preempt_enable();
++		/*
++		 * Try to push this task off of this CPU.
++		 */
++		if (!migrate_me()) {
++			preempt_disable();
++			hp = &__get_cpu_var(hotplug_pcp);
++			if (!hp->grab_lock) {
++				/*
++				 * Just let it continue it's already pinned
++				 * or about to sleep.
++				 */
++				force = 1;
++				goto retry;
++			}
++			preempt_enable();
++		}
++	}
++	preempt_disable();
++	goto retry;
++}
++
++/**
++ * unpin_current_cpu - Allow unplug of current cpu
++ *
++ * Must be called with preemption or interrupts disabled!
++ */
++void unpin_current_cpu(void)
++{
++	struct hotplug_pcp *hp = &__get_cpu_var(hotplug_pcp);
++
++	WARN_ON(hp->refcount <= 0);
++
++	/* This is safe. sync_unplug_thread is pinned to this cpu */
++	if (!--hp->refcount && hp->unplug && hp->unplug != current)
++		wake_up_process(hp->unplug);
++}
++
++static void wait_for_pinned_cpus(struct hotplug_pcp *hp)
++{
++	set_current_state(TASK_UNINTERRUPTIBLE);
++	while (hp->refcount) {
++		schedule_preempt_disabled();
++		set_current_state(TASK_UNINTERRUPTIBLE);
++	}
++}
++
++static int sync_unplug_thread(void *data)
++{
++	struct hotplug_pcp *hp = data;
++
++	wait_for_completion(&hp->unplug_wait);
++	preempt_disable();
++	hp->unplug = current;
++	wait_for_pinned_cpus(hp);
++
++	/*
++	 * This thread will synchronize the cpu_down() with threads
++	 * that have pinned the CPU. When the pinned CPU count reaches
++	 * zero, we inform the cpu_down code to continue to the next step.
++	 */
++	set_current_state(TASK_UNINTERRUPTIBLE);
++	preempt_enable();
++	complete(&hp->synced);
++
++	/*
++	 * If all succeeds, the next step will need tasks to wait till
++	 * the CPU is offline before continuing. To do this, the grab_lock
++	 * is set and tasks going into pin_current_cpu() will block on the
++	 * mutex. But we still need to wait for those that are already in
++	 * pinned CPU sections. If the cpu_down() failed, the kthread_should_stop()
++	 * will kick this thread out.
++	 */
++	while (!hp->grab_lock && !kthread_should_stop()) {
++		schedule();
++		set_current_state(TASK_UNINTERRUPTIBLE);
++	}
++
++	/* Make sure grab_lock is seen before we see a stale completion */
++	smp_mb();
++
++	/*
++	 * Now just before cpu_down() enters stop machine, we need to make
++	 * sure all tasks that are in pinned CPU sections are out, and new
++	 * tasks will now grab the lock, keeping them from entering pinned
++	 * CPU sections.
++	 */
++	if (!kthread_should_stop()) {
++		preempt_disable();
++		wait_for_pinned_cpus(hp);
++		preempt_enable();
++		complete(&hp->synced);
++	}
++
++	set_current_state(TASK_UNINTERRUPTIBLE);
++	while (!kthread_should_stop()) {
++		schedule();
++		set_current_state(TASK_UNINTERRUPTIBLE);
++	}
++	set_current_state(TASK_RUNNING);
++
++	/*
++	 * Force this thread off this CPU as it's going down and
++	 * we don't want any more work on this CPU.
++	 */
++	current->flags &= ~PF_NO_SETAFFINITY;
++	do_set_cpus_allowed(current, cpu_present_mask);
++	migrate_me();
++	return 0;
++}
++
++static void __cpu_unplug_sync(struct hotplug_pcp *hp)
++{
++	wake_up_process(hp->sync_tsk);
++	wait_for_completion(&hp->synced);
++}
++
++static void __cpu_unplug_wait(unsigned int cpu)
++{
++	struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
++
++	complete(&hp->unplug_wait);
++	wait_for_completion(&hp->synced);
++}
++
++/*
++ * Start the sync_unplug_thread on the target cpu and wait for it to
++ * complete.
++ */
++static int cpu_unplug_begin(unsigned int cpu)
++{
++	struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
++	int err;
++
++	/* Protected by cpu_hotplug.lock */
++	if (!hp->mutex_init) {
++#ifdef CONFIG_PREEMPT_RT_FULL
++		spin_lock_init(&hp->lock);
++#else
++		mutex_init(&hp->mutex);
++#endif
++		hp->mutex_init = 1;
++	}
++
++	/* Inform the scheduler to migrate tasks off this CPU */
++	tell_sched_cpu_down_begin(cpu);
++
++	init_completion(&hp->synced);
++	init_completion(&hp->unplug_wait);
++
++	hp->sync_tsk = kthread_create(sync_unplug_thread, hp, "sync_unplug/%d", cpu);
++	if (IS_ERR(hp->sync_tsk)) {
++		err = PTR_ERR(hp->sync_tsk);
++		hp->sync_tsk = NULL;
++		return err;
++	}
++	kthread_bind(hp->sync_tsk, cpu);
++
++	/*
++	 * Wait for tasks to get out of the pinned sections,
++	 * it's still OK if new tasks enter. Some CPU notifiers will
++	 * wait for tasks that are going to enter these sections and
++	 * we must not have them block.
++	 */
++	wake_up_process(hp->sync_tsk);
++	return 0;
++}
++
++static void cpu_unplug_sync(unsigned int cpu)
++{
++	struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
++
++	init_completion(&hp->synced);
++	/* The completion needs to be initialzied before setting grab_lock */
++	smp_wmb();
++
++	/* Grab the mutex before setting grab_lock */
++	hotplug_lock(hp);
++	hp->grab_lock = 1;
++
++	/*
++	 * The CPU notifiers have been completed.
++	 * Wait for tasks to get out of pinned CPU sections and have new
++	 * tasks block until the CPU is completely down.
++	 */
++	__cpu_unplug_sync(hp);
++
++	/* All done with the sync thread */
++	kthread_stop(hp->sync_tsk);
++	hp->sync_tsk = NULL;
++}
++
++static void cpu_unplug_done(unsigned int cpu)
++{
++	struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
++
++	hp->unplug = NULL;
++	/* Let all tasks know cpu unplug is finished before cleaning up */
++	smp_wmb();
++
++	if (hp->sync_tsk)
++		kthread_stop(hp->sync_tsk);
++
++	if (hp->grab_lock) {
++		hotplug_unlock(hp);
++		/* protected by cpu_hotplug.lock */
++		hp->grab_lock = 0;
++	}
++	tell_sched_cpu_down_done(cpu);
++}
++
+ void get_online_cpus(void)
+ {
+ 	might_sleep();
+@@ -102,6 +386,7 @@
+ {
+ 	if (cpu_hotplug.active_writer == current)
+ 		return true;
++
+ 	if (!mutex_trylock(&cpu_hotplug.lock))
+ 		return false;
+ 	cpuhp_lock_acquire_tryread();
+@@ -349,13 +634,15 @@
+ /* Requires cpu_add_remove_lock to be held */
+ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
+ {
+-	int err, nr_calls = 0;
++	int mycpu, err, nr_calls = 0;
+ 	void *hcpu = (void *)(long)cpu;
+ 	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
+ 	struct take_cpu_down_param tcd_param = {
+ 		.mod = mod,
+ 		.hcpu = hcpu,
+ 	};
++	cpumask_var_t cpumask;
++	cpumask_var_t cpumask_org;
+ 
+ 	if (num_online_cpus() == 1)
+ 		return -EBUSY;
+@@ -363,7 +650,34 @@
+ 	if (!cpu_online(cpu))
+ 		return -EINVAL;
+ 
++	/* Move the downtaker off the unplug cpu */
++	if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
++		return -ENOMEM;
++	if (!alloc_cpumask_var(&cpumask_org, GFP_KERNEL))  {
++		free_cpumask_var(cpumask);
++		return -ENOMEM;
++	}
++
++	cpumask_copy(cpumask_org, tsk_cpus_allowed(current));
++	cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu));
++	set_cpus_allowed_ptr(current, cpumask);
++	free_cpumask_var(cpumask);
++	migrate_disable();
++	mycpu = smp_processor_id();
++	if (mycpu == cpu) {
++		printk(KERN_ERR "Yuck! Still on unplug CPU\n!");
++		migrate_enable();
++		err = -EBUSY;
++		goto restore_cpus;
++	}
++	migrate_enable();
++
+ 	cpu_hotplug_begin();
++	err = cpu_unplug_begin(cpu);
++	if (err) {
++		printk("cpu_unplug_begin(%d) failed\n", cpu);
++		goto out_cancel;
++	}
+ 
+ 	err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
+ 	if (err) {
+@@ -389,8 +703,12 @@
+ #endif
+ 	synchronize_rcu();
+ 
++	__cpu_unplug_wait(cpu);
+ 	smpboot_park_threads(cpu);
+ 
++	/* Notifiers are done. Don't let any more tasks pin this CPU. */
++	cpu_unplug_sync(cpu);
++
+ 	/*
+ 	 * So now all preempt/rcu users must observe !cpu_active().
+ 	 */
+@@ -423,9 +741,14 @@
+ 	check_for_tasks(cpu);
+ 
+ out_release:
++	cpu_unplug_done(cpu);
++out_cancel:
+ 	cpu_hotplug_done();
+ 	if (!err)
+ 		cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
++restore_cpus:
++	set_cpus_allowed_ptr(current, cpumask_org);
++	free_cpumask_var(cpumask_org);
+ 	return err;
+ }
+ 
+diff -Nur linux-3.18.8.orig/kernel/debug/kdb/kdb_io.c linux-3.18.8/kernel/debug/kdb/kdb_io.c
+--- linux-3.18.8.orig/kernel/debug/kdb/kdb_io.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/debug/kdb/kdb_io.c	2015-03-03 08:05:18.000000000 +0100
+@@ -554,7 +554,6 @@
+ 	int linecount;
+ 	int colcount;
+ 	int logging, saved_loglevel = 0;
+-	int saved_trap_printk;
+ 	int got_printf_lock = 0;
+ 	int retlen = 0;
+ 	int fnd, len;
+@@ -565,8 +564,6 @@
+ 	unsigned long uninitialized_var(flags);
+ 
+ 	preempt_disable();
+-	saved_trap_printk = kdb_trap_printk;
+-	kdb_trap_printk = 0;
+ 
+ 	/* Serialize kdb_printf if multiple cpus try to write at once.
+ 	 * But if any cpu goes recursive in kdb, just print the output,
+@@ -833,7 +830,6 @@
+ 	} else {
+ 		__release(kdb_printf_lock);
+ 	}
+-	kdb_trap_printk = saved_trap_printk;
+ 	preempt_enable();
+ 	return retlen;
+ }
+@@ -843,9 +839,11 @@
+ 	va_list ap;
+ 	int r;
+ 
++	kdb_trap_printk++;
+ 	va_start(ap, fmt);
+ 	r = vkdb_printf(fmt, ap);
+ 	va_end(ap);
++	kdb_trap_printk--;
+ 
+ 	return r;
+ }
+diff -Nur linux-3.18.8.orig/kernel/events/core.c linux-3.18.8/kernel/events/core.c
+--- linux-3.18.8.orig/kernel/events/core.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/events/core.c	2015-03-03 08:05:18.000000000 +0100
+@@ -6336,6 +6336,7 @@
+ 
+ 	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ 	hwc->hrtimer.function = perf_swevent_hrtimer;
++	hwc->hrtimer.irqsafe = 1;
+ 
+ 	/*
+ 	 * Since hrtimers have a fixed rate, we can do a static freq->period
+diff -Nur linux-3.18.8.orig/kernel/exit.c linux-3.18.8/kernel/exit.c
+--- linux-3.18.8.orig/kernel/exit.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/exit.c	2015-03-03 08:05:18.000000000 +0100
+@@ -147,7 +147,7 @@
+ 	 * Do this under ->siglock, we can race with another thread
+ 	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
+ 	 */
+-	flush_sigqueue(&tsk->pending);
++	flush_task_sigqueue(tsk);
+ 	tsk->sighand = NULL;
+ 	spin_unlock(&sighand->siglock);
+ 
+diff -Nur linux-3.18.8.orig/kernel/fork.c linux-3.18.8/kernel/fork.c
+--- linux-3.18.8.orig/kernel/fork.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/fork.c	2015-03-03 08:05:18.000000000 +0100
+@@ -97,7 +97,7 @@
+ 
+ DEFINE_PER_CPU(unsigned long, process_counts) = 0;
+ 
+-__cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
++DEFINE_RWLOCK(tasklist_lock);  /* outer */
+ 
+ #ifdef CONFIG_PROVE_RCU
+ int lockdep_tasklist_lock_is_held(void)
+@@ -233,7 +233,9 @@
+ 	if (atomic_dec_and_test(&sig->sigcnt))
+ 		free_signal_struct(sig);
+ }
+-
++#ifdef CONFIG_PREEMPT_RT_BASE
++static
++#endif
+ void __put_task_struct(struct task_struct *tsk)
+ {
+ 	WARN_ON(!tsk->exit_state);
+@@ -249,7 +251,18 @@
+ 	if (!profile_handoff_task(tsk))
+ 		free_task(tsk);
+ }
++#ifndef CONFIG_PREEMPT_RT_BASE
+ EXPORT_SYMBOL_GPL(__put_task_struct);
++#else
++void __put_task_struct_cb(struct rcu_head *rhp)
++{
++	struct task_struct *tsk = container_of(rhp, struct task_struct, put_rcu);
++
++	__put_task_struct(tsk);
++
++}
++EXPORT_SYMBOL_GPL(__put_task_struct_cb);
++#endif
+ 
+ void __init __weak arch_task_cache_init(void) { }
+ 
+@@ -643,6 +656,19 @@
+ }
+ EXPORT_SYMBOL_GPL(__mmdrop);
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++/*
++ * RCU callback for delayed mm drop. Not strictly rcu, but we don't
++ * want another facility to make this work.
++ */
++void __mmdrop_delayed(struct rcu_head *rhp)
++{
++	struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop);
++
++	__mmdrop(mm);
++}
++#endif
++
+ /*
+  * Decrement the use count and release all resources for an mm.
+  */
+@@ -1157,6 +1183,9 @@
+  */
+ static void posix_cpu_timers_init(struct task_struct *tsk)
+ {
++#ifdef CONFIG_PREEMPT_RT_BASE
++	tsk->posix_timer_list = NULL;
++#endif
+ 	tsk->cputime_expires.prof_exp = 0;
+ 	tsk->cputime_expires.virt_exp = 0;
+ 	tsk->cputime_expires.sched_exp = 0;
+@@ -1284,6 +1313,7 @@
+ 	spin_lock_init(&p->alloc_lock);
+ 
+ 	init_sigpending(&p->pending);
++	p->sigqueue_cache = NULL;
+ 
+ 	p->utime = p->stime = p->gtime = 0;
+ 	p->utimescaled = p->stimescaled = 0;
+@@ -1291,7 +1321,8 @@
+ 	p->prev_cputime.utime = p->prev_cputime.stime = 0;
+ #endif
+ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+-	seqlock_init(&p->vtime_seqlock);
++	raw_spin_lock_init(&p->vtime_lock);
++	seqcount_init(&p->vtime_seq);
+ 	p->vtime_snap = 0;
+ 	p->vtime_snap_whence = VTIME_SLEEPING;
+ #endif
+@@ -1342,6 +1373,9 @@
+ 	p->hardirq_context = 0;
+ 	p->softirq_context = 0;
+ #endif
++#ifdef CONFIG_PREEMPT_RT_FULL
++	p->pagefault_disabled = 0;
++#endif
+ #ifdef CONFIG_LOCKDEP
+ 	p->lockdep_depth = 0; /* no locks held yet */
+ 	p->curr_chain_key = 0;
+diff -Nur linux-3.18.8.orig/kernel/futex.c linux-3.18.8/kernel/futex.c
+--- linux-3.18.8.orig/kernel/futex.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/futex.c	2015-03-03 08:05:18.000000000 +0100
+@@ -738,7 +738,9 @@
+ 		 * task still owns the PI-state:
+ 		 */
+ 		if (head->next != next) {
++			raw_spin_unlock_irq(&curr->pi_lock);
+ 			spin_unlock(&hb->lock);
++			raw_spin_lock_irq(&curr->pi_lock);
+ 			continue;
+ 		}
+ 
+@@ -1705,6 +1707,16 @@
+ 				requeue_pi_wake_futex(this, &key2, hb2);
+ 				drop_count++;
+ 				continue;
++			} else if (ret == -EAGAIN) {
++				/*
++				 * Waiter was woken by timeout or
++				 * signal and has set pi_blocked_on to
++				 * PI_WAKEUP_INPROGRESS before we
++				 * tried to enqueue it on the rtmutex.
++				 */
++				this->pi_state = NULL;
++				free_pi_state(pi_state);
++				continue;
+ 			} else if (ret) {
+ 				/* -EDEADLK */
+ 				this->pi_state = NULL;
+@@ -2549,7 +2561,7 @@
+ 	struct hrtimer_sleeper timeout, *to = NULL;
+ 	struct rt_mutex_waiter rt_waiter;
+ 	struct rt_mutex *pi_mutex = NULL;
+-	struct futex_hash_bucket *hb;
++	struct futex_hash_bucket *hb, *hb2;
+ 	union futex_key key2 = FUTEX_KEY_INIT;
+ 	struct futex_q q = futex_q_init;
+ 	int res, ret;
+@@ -2574,10 +2586,7 @@
+ 	 * The waiter is allocated on our stack, manipulated by the requeue
+ 	 * code while we sleep on uaddr.
+ 	 */
+-	debug_rt_mutex_init_waiter(&rt_waiter);
+-	RB_CLEAR_NODE(&rt_waiter.pi_tree_entry);
+-	RB_CLEAR_NODE(&rt_waiter.tree_entry);
+-	rt_waiter.task = NULL;
++	rt_mutex_init_waiter(&rt_waiter, false);
+ 
+ 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
+ 	if (unlikely(ret != 0))
+@@ -2608,20 +2617,55 @@
+ 	/* Queue the futex_q, drop the hb lock, wait for wakeup. */
+ 	futex_wait_queue_me(hb, &q, to);
+ 
+-	spin_lock(&hb->lock);
+-	ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
+-	spin_unlock(&hb->lock);
+-	if (ret)
+-		goto out_put_keys;
++	/*
++	 * On RT we must avoid races with requeue and trying to block
++	 * on two mutexes (hb->lock and uaddr2's rtmutex) by
++	 * serializing access to pi_blocked_on with pi_lock.
++	 */
++	raw_spin_lock_irq(&current->pi_lock);
++	if (current->pi_blocked_on) {
++		/*
++		 * We have been requeued or are in the process of
++		 * being requeued.
++		 */
++		raw_spin_unlock_irq(&current->pi_lock);
++	} else {
++		/*
++		 * Setting pi_blocked_on to PI_WAKEUP_INPROGRESS
++		 * prevents a concurrent requeue from moving us to the
++		 * uaddr2 rtmutex. After that we can safely acquire
++		 * (and possibly block on) hb->lock.
++		 */
++		current->pi_blocked_on = PI_WAKEUP_INPROGRESS;
++		raw_spin_unlock_irq(&current->pi_lock);
++
++		spin_lock(&hb->lock);
++
++		/*
++		 * Clean up pi_blocked_on. We might leak it otherwise
++		 * when we succeeded with the hb->lock in the fast
++		 * path.
++		 */
++		raw_spin_lock_irq(&current->pi_lock);
++		current->pi_blocked_on = NULL;
++		raw_spin_unlock_irq(&current->pi_lock);
++
++		ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
++		spin_unlock(&hb->lock);
++		if (ret)
++			goto out_put_keys;
++	}
+ 
+ 	/*
+-	 * In order for us to be here, we know our q.key == key2, and since
+-	 * we took the hb->lock above, we also know that futex_requeue() has
+-	 * completed and we no longer have to concern ourselves with a wakeup
+-	 * race with the atomic proxy lock acquisition by the requeue code. The
+-	 * futex_requeue dropped our key1 reference and incremented our key2
+-	 * reference count.
++	 * In order to be here, we have either been requeued, are in
++	 * the process of being requeued, or requeue successfully
++	 * acquired uaddr2 on our behalf.  If pi_blocked_on was
++	 * non-null above, we may be racing with a requeue.  Do not
++	 * rely on q->lock_ptr to be hb2->lock until after blocking on
++	 * hb->lock or hb2->lock. The futex_requeue dropped our key1
++	 * reference and incremented our key2 reference count.
+ 	 */
++	hb2 = hash_futex(&key2);
+ 
+ 	/* Check if the requeue code acquired the second futex for us. */
+ 	if (!q.rt_waiter) {
+@@ -2630,9 +2674,10 @@
+ 		 * did a lock-steal - fix up the PI-state in that case.
+ 		 */
+ 		if (q.pi_state && (q.pi_state->owner != current)) {
+-			spin_lock(q.lock_ptr);
++			spin_lock(&hb2->lock);
++			BUG_ON(&hb2->lock != q.lock_ptr);
+ 			ret = fixup_pi_state_owner(uaddr2, &q, current);
+-			spin_unlock(q.lock_ptr);
++			spin_unlock(&hb2->lock);
+ 		}
+ 	} else {
+ 		/*
+@@ -2645,7 +2690,8 @@
+ 		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter);
+ 		debug_rt_mutex_free_waiter(&rt_waiter);
+ 
+-		spin_lock(q.lock_ptr);
++		spin_lock(&hb2->lock);
++		BUG_ON(&hb2->lock != q.lock_ptr);
+ 		/*
+ 		 * Fixup the pi_state owner and possibly acquire the lock if we
+ 		 * haven't already.
+diff -Nur linux-3.18.8.orig/kernel/irq/handle.c linux-3.18.8/kernel/irq/handle.c
+--- linux-3.18.8.orig/kernel/irq/handle.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/irq/handle.c	2015-03-03 08:05:18.000000000 +0100
+@@ -133,6 +133,8 @@
+ irqreturn_t
+ handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
+ {
++	struct pt_regs *regs = get_irq_regs();
++	u64 ip = regs ? instruction_pointer(regs) : 0;
+ 	irqreturn_t retval = IRQ_NONE;
+ 	unsigned int flags = 0, irq = desc->irq_data.irq;
+ 
+@@ -173,7 +175,11 @@
+ 		action = action->next;
+ 	} while (action);
+ 
+-	add_interrupt_randomness(irq, flags);
++#ifndef CONFIG_PREEMPT_RT_FULL
++	add_interrupt_randomness(irq, flags, ip);
++#else
++	desc->random_ip = ip;
++#endif
+ 
+ 	if (!noirqdebug)
+ 		note_interrupt(irq, desc, retval);
+diff -Nur linux-3.18.8.orig/kernel/irq/manage.c linux-3.18.8/kernel/irq/manage.c
+--- linux-3.18.8.orig/kernel/irq/manage.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/irq/manage.c	2015-03-03 08:05:18.000000000 +0100
+@@ -22,6 +22,7 @@
+ #include "internals.h"
+ 
+ #ifdef CONFIG_IRQ_FORCED_THREADING
++# ifndef CONFIG_PREEMPT_RT_BASE
+ __read_mostly bool force_irqthreads;
+ 
+ static int __init setup_forced_irqthreads(char *arg)
+@@ -30,6 +31,7 @@
+ 	return 0;
+ }
+ early_param("threadirqs", setup_forced_irqthreads);
++# endif
+ #endif
+ 
+ static void __synchronize_hardirq(struct irq_desc *desc)
+@@ -173,6 +175,62 @@
+ irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++static void _irq_affinity_notify(struct irq_affinity_notify *notify);
++static struct task_struct *set_affinity_helper;
++static LIST_HEAD(affinity_list);
++static DEFINE_RAW_SPINLOCK(affinity_list_lock);
++
++static int set_affinity_thread(void *unused)
++{
++	while (1) {
++		struct irq_affinity_notify *notify;
++		int empty;
++
++		set_current_state(TASK_INTERRUPTIBLE);
++
++		raw_spin_lock_irq(&affinity_list_lock);
++		empty = list_empty(&affinity_list);
++		raw_spin_unlock_irq(&affinity_list_lock);
++
++		if (empty)
++			schedule();
++		if (kthread_should_stop())
++			break;
++		set_current_state(TASK_RUNNING);
++try_next:
++		notify = NULL;
++
++		raw_spin_lock_irq(&affinity_list_lock);
++		if (!list_empty(&affinity_list)) {
++			notify = list_first_entry(&affinity_list,
++					struct irq_affinity_notify, list);
++			list_del_init(&notify->list);
++		}
++		raw_spin_unlock_irq(&affinity_list_lock);
++
++		if (!notify)
++			continue;
++		_irq_affinity_notify(notify);
++		goto try_next;
++	}
++	return 0;
++}
++
++static void init_helper_thread(void)
++{
++	if (set_affinity_helper)
++		return;
++	set_affinity_helper = kthread_run(set_affinity_thread, NULL,
++			"affinity-cb");
++	WARN_ON(IS_ERR(set_affinity_helper));
++}
++#else
++
++static inline void init_helper_thread(void) { }
++
++#endif
++
+ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
+ 			bool force)
+ {
+@@ -211,7 +269,17 @@
+ 
+ 	if (desc->affinity_notify) {
+ 		kref_get(&desc->affinity_notify->kref);
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++		raw_spin_lock(&affinity_list_lock);
++		if (list_empty(&desc->affinity_notify->list))
++			list_add_tail(&affinity_list,
++					&desc->affinity_notify->list);
++		raw_spin_unlock(&affinity_list_lock);
++		wake_up_process(set_affinity_helper);
++#else
+ 		schedule_work(&desc->affinity_notify->work);
++#endif
+ 	}
+ 	irqd_set(data, IRQD_AFFINITY_SET);
+ 
+@@ -246,10 +314,8 @@
+ }
+ EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
+ 
+-static void irq_affinity_notify(struct work_struct *work)
++static void _irq_affinity_notify(struct irq_affinity_notify *notify)
+ {
+-	struct irq_affinity_notify *notify =
+-		container_of(work, struct irq_affinity_notify, work);
+ 	struct irq_desc *desc = irq_to_desc(notify->irq);
+ 	cpumask_var_t cpumask;
+ 	unsigned long flags;
+@@ -271,6 +337,13 @@
+ 	kref_put(&notify->kref, notify->release);
+ }
+ 
++static void irq_affinity_notify(struct work_struct *work)
++{
++	struct irq_affinity_notify *notify =
++		container_of(work, struct irq_affinity_notify, work);
++	_irq_affinity_notify(notify);
++}
++
+ /**
+  *	irq_set_affinity_notifier - control notification of IRQ affinity changes
+  *	@irq:		Interrupt for which to enable/disable notification
+@@ -300,6 +373,8 @@
+ 		notify->irq = irq;
+ 		kref_init(&notify->kref);
+ 		INIT_WORK(&notify->work, irq_affinity_notify);
++		INIT_LIST_HEAD(&notify->list);
++		init_helper_thread();
+ 	}
+ 
+ 	raw_spin_lock_irqsave(&desc->lock, flags);
+@@ -788,7 +863,15 @@
+ 	local_bh_disable();
+ 	ret = action->thread_fn(action->irq, action->dev_id);
+ 	irq_finalize_oneshot(desc, action);
+-	local_bh_enable();
++	/*
++	 * Interrupts which have real time requirements can be set up
++	 * to avoid softirq processing in the thread handler. This is
++	 * safe as these interrupts do not raise soft interrupts.
++	 */
++	if (irq_settings_no_softirq_call(desc))
++		_local_bh_enable();
++	else
++		local_bh_enable();
+ 	return ret;
+ }
+ 
+@@ -871,6 +954,12 @@
+ 		if (action_ret == IRQ_HANDLED)
+ 			atomic_inc(&desc->threads_handled);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++		migrate_disable();
++		add_interrupt_randomness(action->irq, 0,
++				 desc->random_ip ^ (unsigned long) action);
++		migrate_enable();
++#endif
+ 		wake_threads_waitq(desc);
+ 	}
+ 
+@@ -1184,6 +1273,9 @@
+ 			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
+ 		}
+ 
++		if (new->flags & IRQF_NO_SOFTIRQ_CALL)
++			irq_settings_set_no_softirq_call(desc);
++
+ 		/* Set default affinity mask once everything is setup */
+ 		setup_affinity(irq, desc, mask);
+ 
+diff -Nur linux-3.18.8.orig/kernel/irq/settings.h linux-3.18.8/kernel/irq/settings.h
+--- linux-3.18.8.orig/kernel/irq/settings.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/irq/settings.h	2015-03-03 08:05:18.000000000 +0100
+@@ -15,6 +15,7 @@
+ 	_IRQ_NESTED_THREAD	= IRQ_NESTED_THREAD,
+ 	_IRQ_PER_CPU_DEVID	= IRQ_PER_CPU_DEVID,
+ 	_IRQ_IS_POLLED		= IRQ_IS_POLLED,
++	_IRQ_NO_SOFTIRQ_CALL	= IRQ_NO_SOFTIRQ_CALL,
+ 	_IRQF_MODIFY_MASK	= IRQF_MODIFY_MASK,
+ };
+ 
+@@ -28,6 +29,7 @@
+ #define IRQ_NESTED_THREAD	GOT_YOU_MORON
+ #define IRQ_PER_CPU_DEVID	GOT_YOU_MORON
+ #define IRQ_IS_POLLED		GOT_YOU_MORON
++#define IRQ_NO_SOFTIRQ_CALL	GOT_YOU_MORON
+ #undef IRQF_MODIFY_MASK
+ #define IRQF_MODIFY_MASK	GOT_YOU_MORON
+ 
+@@ -38,6 +40,16 @@
+ 	desc->status_use_accessors |= (set & _IRQF_MODIFY_MASK);
+ }
+ 
++static inline bool irq_settings_no_softirq_call(struct irq_desc *desc)
++{
++	return desc->status_use_accessors & _IRQ_NO_SOFTIRQ_CALL;
++}
++
++static inline void irq_settings_set_no_softirq_call(struct irq_desc *desc)
++{
++	desc->status_use_accessors |= _IRQ_NO_SOFTIRQ_CALL;
++}
++
+ static inline bool irq_settings_is_per_cpu(struct irq_desc *desc)
+ {
+ 	return desc->status_use_accessors & _IRQ_PER_CPU;
+diff -Nur linux-3.18.8.orig/kernel/irq/spurious.c linux-3.18.8/kernel/irq/spurious.c
+--- linux-3.18.8.orig/kernel/irq/spurious.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/irq/spurious.c	2015-03-03 08:05:18.000000000 +0100
+@@ -444,6 +444,10 @@
+ 
+ static int __init irqfixup_setup(char *str)
+ {
++#ifdef CONFIG_PREEMPT_RT_BASE
++	pr_warn("irqfixup boot option not supported w/ CONFIG_PREEMPT_RT_BASE\n");
++	return 1;
++#endif
+ 	irqfixup = 1;
+ 	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
+ 	printk(KERN_WARNING "This may impact system performance.\n");
+@@ -456,6 +460,10 @@
+ 
+ static int __init irqpoll_setup(char *str)
+ {
++#ifdef CONFIG_PREEMPT_RT_BASE
++	pr_warn("irqpoll boot option not supported w/ CONFIG_PREEMPT_RT_BASE\n");
++	return 1;
++#endif
+ 	irqfixup = 2;
+ 	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
+ 				"enabled\n");
+diff -Nur linux-3.18.8.orig/kernel/irq_work.c linux-3.18.8/kernel/irq_work.c
+--- linux-3.18.8.orig/kernel/irq_work.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/irq_work.c	2015-03-03 08:05:18.000000000 +0100
+@@ -22,7 +22,9 @@
+ 
+ static DEFINE_PER_CPU(struct llist_head, raised_list);
+ static DEFINE_PER_CPU(struct llist_head, lazy_list);
+-
++#ifdef CONFIG_PREEMPT_RT_FULL
++static DEFINE_PER_CPU(struct llist_head, hirq_work_list);
++#endif
+ /*
+  * Claim the entry so that no one else will poke at it.
+  */
+@@ -49,7 +51,11 @@
+ 	return true;
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++void arch_irq_work_raise(void)
++#else
+ void __weak arch_irq_work_raise(void)
++#endif
+ {
+ 	/*
+ 	 * Lame architectures will get the timer tick callback
+@@ -93,8 +99,21 @@
+ 	/* Queue the entry and raise the IPI if needed. */
+ 	preempt_disable();
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (work->flags & IRQ_WORK_HARD_IRQ) {
++		if (llist_add(&work->llnode, this_cpu_ptr(&hirq_work_list))) {
++			if (work->flags & IRQ_WORK_LAZY) {
++				if (tick_nohz_tick_stopped())
++					arch_irq_work_raise();
++			} else {
++				arch_irq_work_raise();
++			}
++		}
+ 	/* If the work is "lazy", handle it from next tick if any */
++	} else if (work->flags & IRQ_WORK_LAZY) {
++#else
+ 	if (work->flags & IRQ_WORK_LAZY) {
++#endif
+ 		if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
+ 		    tick_nohz_tick_stopped())
+ 			arch_irq_work_raise();
+@@ -116,7 +135,7 @@
+ 	raised = this_cpu_ptr(&raised_list);
+ 	lazy = this_cpu_ptr(&lazy_list);
+ 
+-	if (llist_empty(raised) || arch_irq_work_has_interrupt())
++	if (llist_empty(raised))
+ 		if (llist_empty(lazy))
+ 			return false;
+ 
+@@ -132,7 +151,9 @@
+ 	struct irq_work *work;
+ 	struct llist_node *llnode;
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	BUG_ON(!irqs_disabled());
++#endif
+ 
+ 	if (llist_empty(list))
+ 		return;
+@@ -168,6 +189,12 @@
+  */
+ void irq_work_run(void)
+ {
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (in_irq()) {
++		irq_work_run_list(this_cpu_ptr(&hirq_work_list));
++		return;
++	}
++#endif
+ 	irq_work_run_list(this_cpu_ptr(&raised_list));
+ 	irq_work_run_list(this_cpu_ptr(&lazy_list));
+ }
+@@ -175,9 +202,16 @@
+ 
+ void irq_work_tick(void)
+ {
+-	struct llist_head *raised = &__get_cpu_var(raised_list);
++	struct llist_head *raised;
+ 
+-	if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (in_irq()) {
++		irq_work_run_list(this_cpu_ptr(&hirq_work_list));
++		return;
++	}
++#endif
++	raised = &__get_cpu_var(raised_list);
++	if (!llist_empty(raised))
+ 		irq_work_run_list(raised);
+ 	irq_work_run_list(&__get_cpu_var(lazy_list));
+ }
+diff -Nur linux-3.18.8.orig/kernel/Kconfig.locks linux-3.18.8/kernel/Kconfig.locks
+--- linux-3.18.8.orig/kernel/Kconfig.locks	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/Kconfig.locks	2015-03-03 08:05:18.000000000 +0100
+@@ -225,11 +225,11 @@
+ 
+ config MUTEX_SPIN_ON_OWNER
+ 	def_bool y
+-	depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW
++	depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW && !PREEMPT_RT_FULL
+ 
+ config RWSEM_SPIN_ON_OWNER
+        def_bool y
+-       depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW
++       depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW && !PREEMPT_RT_FULL
+ 
+ config ARCH_USE_QUEUE_RWLOCK
+ 	bool
+diff -Nur linux-3.18.8.orig/kernel/Kconfig.preempt linux-3.18.8/kernel/Kconfig.preempt
+--- linux-3.18.8.orig/kernel/Kconfig.preempt	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/Kconfig.preempt	2015-03-03 08:05:18.000000000 +0100
+@@ -1,3 +1,16 @@
++config PREEMPT
++	bool
++	select PREEMPT_COUNT
++
++config PREEMPT_RT_BASE
++	bool
++	select PREEMPT
++
++config HAVE_PREEMPT_LAZY
++	bool
++
++config PREEMPT_LAZY
++	def_bool y if HAVE_PREEMPT_LAZY && PREEMPT_RT_FULL
+ 
+ choice
+ 	prompt "Preemption Model"
+@@ -33,9 +46,9 @@
+ 
+ 	  Select this if you are building a kernel for a desktop system.
+ 
+-config PREEMPT
++config PREEMPT__LL
+ 	bool "Preemptible Kernel (Low-Latency Desktop)"
+-	select PREEMPT_COUNT
++	select PREEMPT
+ 	select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
+ 	help
+ 	  This option reduces the latency of the kernel by making
+@@ -52,6 +65,22 @@
+ 	  embedded system with latency requirements in the milliseconds
+ 	  range.
+ 
++config PREEMPT_RTB
++	bool "Preemptible Kernel (Basic RT)"
++	select PREEMPT_RT_BASE
++	help
++	  This option is basically the same as (Low-Latency Desktop) but
++	  enables changes which are preliminary for the full preemptible
++	  RT kernel.
++
++config PREEMPT_RT_FULL
++	bool "Fully Preemptible Kernel (RT)"
++	depends on IRQ_FORCED_THREADING
++	select PREEMPT_RT_BASE
++	select PREEMPT_RCU
++	help
++	  All and everything
++
+ endchoice
+ 
+ config PREEMPT_COUNT
+diff -Nur linux-3.18.8.orig/kernel/ksysfs.c linux-3.18.8/kernel/ksysfs.c
+--- linux-3.18.8.orig/kernel/ksysfs.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/ksysfs.c	2015-03-03 08:05:18.000000000 +0100
+@@ -136,6 +136,15 @@
+ 
+ #endif /* CONFIG_KEXEC */
+ 
++#if defined(CONFIG_PREEMPT_RT_FULL)
++static ssize_t  realtime_show(struct kobject *kobj,
++			      struct kobj_attribute *attr, char *buf)
++{
++	return sprintf(buf, "%d\n", 1);
++}
++KERNEL_ATTR_RO(realtime);
++#endif
++
+ /* whether file capabilities are enabled */
+ static ssize_t fscaps_show(struct kobject *kobj,
+ 				  struct kobj_attribute *attr, char *buf)
+@@ -203,6 +212,9 @@
+ 	&vmcoreinfo_attr.attr,
+ #endif
+ 	&rcu_expedited_attr.attr,
++#ifdef CONFIG_PREEMPT_RT_FULL
++	&realtime_attr.attr,
++#endif
+ 	NULL
+ };
+ 
+diff -Nur linux-3.18.8.orig/kernel/locking/lglock.c linux-3.18.8/kernel/locking/lglock.c
+--- linux-3.18.8.orig/kernel/locking/lglock.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/lglock.c	2015-03-03 08:05:18.000000000 +0100
+@@ -4,6 +4,15 @@
+ #include <linux/cpu.h>
+ #include <linux/string.h>
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++# define lg_lock_ptr		arch_spinlock_t
++# define lg_do_lock(l)		arch_spin_lock(l)
++# define lg_do_unlock(l)	arch_spin_unlock(l)
++#else
++# define lg_lock_ptr		struct rt_mutex
++# define lg_do_lock(l)		__rt_spin_lock(l)
++# define lg_do_unlock(l)	__rt_spin_unlock(l)
++#endif
+ /*
+  * Note there is no uninit, so lglocks cannot be defined in
+  * modules (but it's fine to use them from there)
+@@ -12,51 +21,60 @@
+ 
+ void lg_lock_init(struct lglock *lg, char *name)
+ {
++#ifdef CONFIG_PREEMPT_RT_FULL
++	int i;
++
++	for_each_possible_cpu(i) {
++		struct rt_mutex *lock = per_cpu_ptr(lg->lock, i);
++
++		rt_mutex_init(lock);
++	}
++#endif
+ 	LOCKDEP_INIT_MAP(&lg->lock_dep_map, name, &lg->lock_key, 0);
+ }
+ EXPORT_SYMBOL(lg_lock_init);
+ 
+ void lg_local_lock(struct lglock *lg)
+ {
+-	arch_spinlock_t *lock;
++	lg_lock_ptr *lock;
+ 
+-	preempt_disable();
++	migrate_disable();
+ 	lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
+ 	lock = this_cpu_ptr(lg->lock);
+-	arch_spin_lock(lock);
++	lg_do_lock(lock);
+ }
+ EXPORT_SYMBOL(lg_local_lock);
+ 
+ void lg_local_unlock(struct lglock *lg)
+ {
+-	arch_spinlock_t *lock;
++	lg_lock_ptr *lock;
+ 
+ 	lock_release(&lg->lock_dep_map, 1, _RET_IP_);
+ 	lock = this_cpu_ptr(lg->lock);
+-	arch_spin_unlock(lock);
+-	preempt_enable();
++	lg_do_unlock(lock);
++	migrate_enable();
+ }
+ EXPORT_SYMBOL(lg_local_unlock);
+ 
+ void lg_local_lock_cpu(struct lglock *lg, int cpu)
+ {
+-	arch_spinlock_t *lock;
++	lg_lock_ptr *lock;
+ 
+-	preempt_disable();
++	preempt_disable_nort();
+ 	lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
+ 	lock = per_cpu_ptr(lg->lock, cpu);
+-	arch_spin_lock(lock);
++	lg_do_lock(lock);
+ }
+ EXPORT_SYMBOL(lg_local_lock_cpu);
+ 
+ void lg_local_unlock_cpu(struct lglock *lg, int cpu)
+ {
+-	arch_spinlock_t *lock;
++	lg_lock_ptr *lock;
+ 
+ 	lock_release(&lg->lock_dep_map, 1, _RET_IP_);
+ 	lock = per_cpu_ptr(lg->lock, cpu);
+-	arch_spin_unlock(lock);
+-	preempt_enable();
++	lg_do_unlock(lock);
++	preempt_enable_nort();
+ }
+ EXPORT_SYMBOL(lg_local_unlock_cpu);
+ 
+@@ -64,12 +82,12 @@
+ {
+ 	int i;
+ 
+-	preempt_disable();
++	preempt_disable_nort();
+ 	lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
+ 	for_each_possible_cpu(i) {
+-		arch_spinlock_t *lock;
++		lg_lock_ptr *lock;
+ 		lock = per_cpu_ptr(lg->lock, i);
+-		arch_spin_lock(lock);
++		lg_do_lock(lock);
+ 	}
+ }
+ EXPORT_SYMBOL(lg_global_lock);
+@@ -80,10 +98,35 @@
+ 
+ 	lock_release(&lg->lock_dep_map, 1, _RET_IP_);
+ 	for_each_possible_cpu(i) {
+-		arch_spinlock_t *lock;
++		lg_lock_ptr *lock;
+ 		lock = per_cpu_ptr(lg->lock, i);
+-		arch_spin_unlock(lock);
++		lg_do_unlock(lock);
+ 	}
+-	preempt_enable();
++	preempt_enable_nort();
+ }
+ EXPORT_SYMBOL(lg_global_unlock);
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * HACK: If you use this, you get to keep the pieces.
++ * Used in queue_stop_cpus_work() when stop machinery
++ * is called from inactive CPU, so we can't schedule.
++ */
++# define lg_do_trylock_relax(l)			\
++	do {					\
++		while (!__rt_spin_trylock(l))	\
++			cpu_relax();		\
++	} while (0)
++
++void lg_global_trylock_relax(struct lglock *lg)
++{
++	int i;
++
++	lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
++	for_each_possible_cpu(i) {
++		lg_lock_ptr *lock;
++		lock = per_cpu_ptr(lg->lock, i);
++		lg_do_trylock_relax(lock);
++	}
++}
++#endif
+diff -Nur linux-3.18.8.orig/kernel/locking/lockdep.c linux-3.18.8/kernel/locking/lockdep.c
+--- linux-3.18.8.orig/kernel/locking/lockdep.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/lockdep.c	2015-03-03 08:05:18.000000000 +0100
+@@ -3542,6 +3542,7 @@
+ 		}
+ 	}
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	/*
+ 	 * We dont accurately track softirq state in e.g.
+ 	 * hardirq contexts (such as on 4KSTACKS), so only
+@@ -3556,6 +3557,7 @@
+ 			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+ 		}
+ 	}
++#endif
+ 
+ 	if (!debug_locks)
+ 		print_irqtrace_events(current);
+diff -Nur linux-3.18.8.orig/kernel/locking/Makefile linux-3.18.8/kernel/locking/Makefile
+--- linux-3.18.8.orig/kernel/locking/Makefile	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/Makefile	2015-03-03 08:05:18.000000000 +0100
+@@ -1,5 +1,5 @@
+ 
+-obj-y += mutex.o semaphore.o rwsem.o mcs_spinlock.o
++obj-y += semaphore.o mcs_spinlock.o
+ 
+ ifdef CONFIG_FUNCTION_TRACER
+ CFLAGS_REMOVE_lockdep.o = -pg
+@@ -8,7 +8,11 @@
+ CFLAGS_REMOVE_rtmutex-debug.o = -pg
+ endif
+ 
++ifneq ($(CONFIG_PREEMPT_RT_FULL),y)
++obj-y += mutex.o
+ obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
++obj-y += rwsem.o
++endif
+ obj-$(CONFIG_LOCKDEP) += lockdep.o
+ ifeq ($(CONFIG_PROC_FS),y)
+ obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
+@@ -21,8 +25,11 @@
+ obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
+ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
+ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
++ifneq ($(CONFIG_PREEMPT_RT_FULL),y)
+ obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
+ obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
++endif
+ obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
++obj-$(CONFIG_PREEMPT_RT_FULL) += rt.o
+ obj-$(CONFIG_QUEUE_RWLOCK) += qrwlock.o
+ obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
+diff -Nur linux-3.18.8.orig/kernel/locking/percpu-rwsem.c linux-3.18.8/kernel/locking/percpu-rwsem.c
+--- linux-3.18.8.orig/kernel/locking/percpu-rwsem.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/percpu-rwsem.c	2015-03-03 08:05:18.000000000 +0100
+@@ -84,8 +84,12 @@
+ 
+ 	down_read(&brw->rw_sem);
+ 	atomic_inc(&brw->slow_read_ctr);
++#ifdef CONFIG_PREEMPT_RT_FULL
++	up_read(&brw->rw_sem);
++#else
+ 	/* avoid up_read()->rwsem_release() */
+ 	__up_read(&brw->rw_sem);
++#endif
+ }
+ 
+ void percpu_up_read(struct percpu_rw_semaphore *brw)
+diff -Nur linux-3.18.8.orig/kernel/locking/rt.c linux-3.18.8/kernel/locking/rt.c
+--- linux-3.18.8.orig/kernel/locking/rt.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/kernel/locking/rt.c	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,437 @@
++/*
++ * kernel/rt.c
++ *
++ * Real-Time Preemption Support
++ *
++ * started by Ingo Molnar:
++ *
++ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
++ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
++ *
++ * historic credit for proving that Linux spinlocks can be implemented via
++ * RT-aware mutexes goes to many people: The Pmutex project (Dirk Grambow
++ * and others) who prototyped it on 2.4 and did lots of comparative
++ * research and analysis; TimeSys, for proving that you can implement a
++ * fully preemptible kernel via the use of IRQ threading and mutexes;
++ * Bill Huey for persuasively arguing on lkml that the mutex model is the
++ * right one; and to MontaVista, who ported pmutexes to 2.6.
++ *
++ * This code is a from-scratch implementation and is not based on pmutexes,
++ * but the idea of converting spinlocks to mutexes is used here too.
++ *
++ * lock debugging, locking tree, deadlock detection:
++ *
++ *  Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
++ *  Released under the General Public License (GPL).
++ *
++ * Includes portions of the generic R/W semaphore implementation from:
++ *
++ *  Copyright (c) 2001   David Howells (dhowells@redhat.com).
++ *  - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
++ *  - Derived also from comments by Linus
++ *
++ * Pending ownership of locks and ownership stealing:
++ *
++ *  Copyright (C) 2005, Kihon Technologies Inc., Steven Rostedt
++ *
++ *   (also by Steven Rostedt)
++ *    - Converted single pi_lock to individual task locks.
++ *
++ * By Esben Nielsen:
++ *    Doing priority inheritance with help of the scheduler.
++ *
++ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
++ *  - major rework based on Esben Nielsens initial patch
++ *  - replaced thread_info references by task_struct refs
++ *  - removed task->pending_owner dependency
++ *  - BKL drop/reacquire for semaphore style locks to avoid deadlocks
++ *    in the scheduler return path as discussed with Steven Rostedt
++ *
++ *  Copyright (C) 2006, Kihon Technologies Inc.
++ *    Steven Rostedt <rostedt@goodmis.org>
++ *  - debugged and patched Thomas Gleixner's rework.
++ *  - added back the cmpxchg to the rework.
++ *  - turned atomic require back on for SMP.
++ */
++
++#include <linux/spinlock.h>
++#include <linux/rtmutex.h>
++#include <linux/sched.h>
++#include <linux/delay.h>
++#include <linux/module.h>
++#include <linux/kallsyms.h>
++#include <linux/syscalls.h>
++#include <linux/interrupt.h>
++#include <linux/plist.h>
++#include <linux/fs.h>
++#include <linux/futex.h>
++#include <linux/hrtimer.h>
++
++#include "rtmutex_common.h"
++
++/*
++ * struct mutex functions
++ */
++void __mutex_do_init(struct mutex *mutex, const char *name,
++		     struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held lock:
++	 */
++	debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
++	lockdep_init_map(&mutex->dep_map, name, key, 0);
++#endif
++	mutex->lock.save_state = 0;
++}
++EXPORT_SYMBOL(__mutex_do_init);
++
++void __lockfunc _mutex_lock(struct mutex *lock)
++{
++	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	rt_mutex_lock(&lock->lock);
++}
++EXPORT_SYMBOL(_mutex_lock);
++
++int __lockfunc _mutex_lock_interruptible(struct mutex *lock)
++{
++	int ret;
++
++	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	ret = rt_mutex_lock_interruptible(&lock->lock);
++	if (ret)
++		mutex_release(&lock->dep_map, 1, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_interruptible);
++
++int __lockfunc _mutex_lock_killable(struct mutex *lock)
++{
++	int ret;
++
++	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	ret = rt_mutex_lock_killable(&lock->lock);
++	if (ret)
++		mutex_release(&lock->dep_map, 1, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_killable);
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass)
++{
++	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
++	rt_mutex_lock(&lock->lock);
++}
++EXPORT_SYMBOL(_mutex_lock_nested);
++
++void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
++{
++	mutex_acquire_nest(&lock->dep_map, 0, 0, nest, _RET_IP_);
++	rt_mutex_lock(&lock->lock);
++}
++EXPORT_SYMBOL(_mutex_lock_nest_lock);
++
++int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass)
++{
++	int ret;
++
++	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
++	ret = rt_mutex_lock_interruptible(&lock->lock);
++	if (ret)
++		mutex_release(&lock->dep_map, 1, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_interruptible_nested);
++
++int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass)
++{
++	int ret;
++
++	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
++	ret = rt_mutex_lock_killable(&lock->lock);
++	if (ret)
++		mutex_release(&lock->dep_map, 1, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_killable_nested);
++#endif
++
++int __lockfunc _mutex_trylock(struct mutex *lock)
++{
++	int ret = rt_mutex_trylock(&lock->lock);
++
++	if (ret)
++		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_trylock);
++
++void __lockfunc _mutex_unlock(struct mutex *lock)
++{
++	mutex_release(&lock->dep_map, 1, _RET_IP_);
++	rt_mutex_unlock(&lock->lock);
++}
++EXPORT_SYMBOL(_mutex_unlock);
++
++/*
++ * rwlock_t functions
++ */
++int __lockfunc rt_write_trylock(rwlock_t *rwlock)
++{
++	int ret;
++
++	migrate_disable();
++	ret = rt_mutex_trylock(&rwlock->lock);
++	if (ret)
++		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
++	else
++		migrate_enable();
++
++	return ret;
++}
++EXPORT_SYMBOL(rt_write_trylock);
++
++int __lockfunc rt_write_trylock_irqsave(rwlock_t *rwlock, unsigned long *flags)
++{
++	int ret;
++
++	*flags = 0;
++	ret = rt_write_trylock(rwlock);
++	return ret;
++}
++EXPORT_SYMBOL(rt_write_trylock_irqsave);
++
++int __lockfunc rt_read_trylock(rwlock_t *rwlock)
++{
++	struct rt_mutex *lock = &rwlock->lock;
++	int ret = 1;
++
++	/*
++	 * recursive read locks succeed when current owns the lock,
++	 * but not when read_depth == 0 which means that the lock is
++	 * write locked.
++	 */
++	if (rt_mutex_owner(lock) != current) {
++		migrate_disable();
++		ret = rt_mutex_trylock(lock);
++		if (ret)
++			rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
++		else
++			migrate_enable();
++
++	} else if (!rwlock->read_depth) {
++		ret = 0;
++	}
++
++	if (ret)
++		rwlock->read_depth++;
++
++	return ret;
++}
++EXPORT_SYMBOL(rt_read_trylock);
++
++void __lockfunc rt_write_lock(rwlock_t *rwlock)
++{
++	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
++	migrate_disable();
++	__rt_spin_lock(&rwlock->lock);
++}
++EXPORT_SYMBOL(rt_write_lock);
++
++void __lockfunc rt_read_lock(rwlock_t *rwlock)
++{
++	struct rt_mutex *lock = &rwlock->lock;
++
++
++	/*
++	 * recursive read locks succeed when current owns the lock
++	 */
++	if (rt_mutex_owner(lock) != current) {
++		migrate_disable();
++		rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
++		__rt_spin_lock(lock);
++	}
++	rwlock->read_depth++;
++}
++
++EXPORT_SYMBOL(rt_read_lock);
++
++void __lockfunc rt_write_unlock(rwlock_t *rwlock)
++{
++	/* NOTE: we always pass in '1' for nested, for simplicity */
++	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
++	__rt_spin_unlock(&rwlock->lock);
++	migrate_enable();
++}
++EXPORT_SYMBOL(rt_write_unlock);
++
++void __lockfunc rt_read_unlock(rwlock_t *rwlock)
++{
++	/* Release the lock only when read_depth is down to 0 */
++	if (--rwlock->read_depth == 0) {
++		rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
++		__rt_spin_unlock(&rwlock->lock);
++		migrate_enable();
++	}
++}
++EXPORT_SYMBOL(rt_read_unlock);
++
++unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock)
++{
++	rt_write_lock(rwlock);
++
++	return 0;
++}
++EXPORT_SYMBOL(rt_write_lock_irqsave);
++
++unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock)
++{
++	rt_read_lock(rwlock);
++
++	return 0;
++}
++EXPORT_SYMBOL(rt_read_lock_irqsave);
++
++void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held lock:
++	 */
++	debug_check_no_locks_freed((void *)rwlock, sizeof(*rwlock));
++	lockdep_init_map(&rwlock->dep_map, name, key, 0);
++#endif
++	rwlock->lock.save_state = 1;
++	rwlock->read_depth = 0;
++}
++EXPORT_SYMBOL(__rt_rwlock_init);
++
++/*
++ * rw_semaphores
++ */
++
++void  rt_up_write(struct rw_semaphore *rwsem)
++{
++	rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
++	rt_mutex_unlock(&rwsem->lock);
++}
++EXPORT_SYMBOL(rt_up_write);
++
++void  rt_up_read(struct rw_semaphore *rwsem)
++{
++	rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
++	rt_mutex_unlock(&rwsem->lock);
++}
++EXPORT_SYMBOL(rt_up_read);
++
++/*
++ * downgrade a write lock into a read lock
++ * - just wake up any readers at the front of the queue
++ */
++void  rt_downgrade_write(struct rw_semaphore *rwsem)
++{
++	BUG_ON(rt_mutex_owner(&rwsem->lock) != current);
++}
++EXPORT_SYMBOL(rt_downgrade_write);
++
++int  rt_down_write_trylock(struct rw_semaphore *rwsem)
++{
++	int ret = rt_mutex_trylock(&rwsem->lock);
++
++	if (ret)
++		rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(rt_down_write_trylock);
++
++void  rt_down_write(struct rw_semaphore *rwsem)
++{
++	rwsem_acquire(&rwsem->dep_map, 0, 0, _RET_IP_);
++	rt_mutex_lock(&rwsem->lock);
++}
++EXPORT_SYMBOL(rt_down_write);
++
++void  rt_down_write_nested(struct rw_semaphore *rwsem, int subclass)
++{
++	rwsem_acquire(&rwsem->dep_map, subclass, 0, _RET_IP_);
++	rt_mutex_lock(&rwsem->lock);
++}
++EXPORT_SYMBOL(rt_down_write_nested);
++
++void rt_down_write_nested_lock(struct rw_semaphore *rwsem,
++		struct lockdep_map *nest)
++{
++	rwsem_acquire_nest(&rwsem->dep_map, 0, 0, nest, _RET_IP_);
++	rt_mutex_lock(&rwsem->lock);
++}
++EXPORT_SYMBOL(rt_down_write_nested_lock);
++
++int  rt_down_read_trylock(struct rw_semaphore *rwsem)
++{
++	int ret;
++
++	ret = rt_mutex_trylock(&rwsem->lock);
++	if (ret)
++		rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
++
++	return ret;
++}
++EXPORT_SYMBOL(rt_down_read_trylock);
++
++static void __rt_down_read(struct rw_semaphore *rwsem, int subclass)
++{
++	rwsem_acquire(&rwsem->dep_map, subclass, 0, _RET_IP_);
++	rt_mutex_lock(&rwsem->lock);
++}
++
++void  rt_down_read(struct rw_semaphore *rwsem)
++{
++	__rt_down_read(rwsem, 0);
++}
++EXPORT_SYMBOL(rt_down_read);
++
++void  rt_down_read_nested(struct rw_semaphore *rwsem, int subclass)
++{
++	__rt_down_read(rwsem, subclass);
++}
++EXPORT_SYMBOL(rt_down_read_nested);
++
++void  __rt_rwsem_init(struct rw_semaphore *rwsem, const char *name,
++			      struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held lock:
++	 */
++	debug_check_no_locks_freed((void *)rwsem, sizeof(*rwsem));
++	lockdep_init_map(&rwsem->dep_map, name, key, 0);
++#endif
++	rwsem->lock.save_state = 0;
++}
++EXPORT_SYMBOL(__rt_rwsem_init);
++
++/**
++ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
++ * @cnt: the atomic which we are to dec
++ * @lock: the mutex to return holding if we dec to 0
++ *
++ * return true and hold lock if we dec to 0, return false otherwise
++ */
++int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
++{
++	/* dec if we can't possibly hit 0 */
++	if (atomic_add_unless(cnt, -1, 1))
++		return 0;
++	/* we might hit 0, so take the lock */
++	mutex_lock(lock);
++	if (!atomic_dec_and_test(cnt)) {
++		/* when we actually did the dec, we didn't hit 0 */
++		mutex_unlock(lock);
++		return 0;
++	}
++	/* we hit 0, and we hold the lock */
++	return 1;
++}
++EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
+diff -Nur linux-3.18.8.orig/kernel/locking/rtmutex.c linux-3.18.8/kernel/locking/rtmutex.c
+--- linux-3.18.8.orig/kernel/locking/rtmutex.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/rtmutex.c	2015-03-03 08:05:18.000000000 +0100
+@@ -7,6 +7,11 @@
+  *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+  *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
+  *  Copyright (C) 2006 Esben Nielsen
++ *  Adaptive Spinlocks:
++ *  Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
++ *				     and Peter Morreale,
++ * Adaptive Spinlocks simplification:
++ *  Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
+  *
+  *  See Documentation/locking/rt-mutex-design.txt for details.
+  */
+@@ -16,6 +21,7 @@
+ #include <linux/sched/rt.h>
+ #include <linux/sched/deadline.h>
+ #include <linux/timer.h>
++#include <linux/ww_mutex.h>
+ 
+ #include "rtmutex_common.h"
+ 
+@@ -69,6 +75,12 @@
+ 		clear_rt_mutex_waiters(lock);
+ }
+ 
++static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
++{
++	return waiter && waiter != PI_WAKEUP_INPROGRESS &&
++		waiter != PI_REQUEUE_INPROGRESS;
++}
++
+ /*
+  * We can speed up the acquire/release, if the architecture
+  * supports cmpxchg and if there's no debugging state to be set up
+@@ -333,6 +345,14 @@
+ 	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
+ }
+ 
++static void rt_mutex_wake_waiter(struct rt_mutex_waiter *waiter)
++{
++	if (waiter->savestate)
++		wake_up_lock_sleeper(waiter->task);
++	else
++		wake_up_process(waiter->task);
++}
++
+ /*
+  * Max number of times we'll walk the boosting chain:
+  */
+@@ -340,7 +360,8 @@
+ 
+ static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
+ {
+-	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
++	return rt_mutex_real_waiter(p->pi_blocked_on) ?
++		p->pi_blocked_on->lock : NULL;
+ }
+ 
+ /*
+@@ -477,7 +498,7 @@
+ 	 * reached or the state of the chain has changed while we
+ 	 * dropped the locks.
+ 	 */
+-	if (!waiter)
++	if (!rt_mutex_real_waiter(waiter))
+ 		goto out_unlock_pi;
+ 
+ 	/*
+@@ -639,13 +660,16 @@
+ 	 * follow here. This is the end of the chain we are walking.
+ 	 */
+ 	if (!rt_mutex_owner(lock)) {
++		struct rt_mutex_waiter *lock_top_waiter;
++
+ 		/*
+ 		 * If the requeue [7] above changed the top waiter,
+ 		 * then we need to wake the new top waiter up to try
+ 		 * to get the lock.
+ 		 */
+-		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
+-			wake_up_process(rt_mutex_top_waiter(lock)->task);
++		lock_top_waiter = rt_mutex_top_waiter(lock);
++		if (prerequeue_top_waiter != lock_top_waiter)
++			rt_mutex_wake_waiter(lock_top_waiter);
+ 		raw_spin_unlock(&lock->wait_lock);
+ 		return 0;
+ 	}
+@@ -738,6 +762,25 @@
+ 	return ret;
+ }
+ 
++
++#define STEAL_NORMAL  0
++#define STEAL_LATERAL 1
++
++/*
++ * Note that RT tasks are excluded from lateral-steals to prevent the
++ * introduction of an unbounded latency
++ */
++static inline int lock_is_stealable(struct task_struct *task,
++				    struct task_struct *pendowner, int mode)
++{
++    if (mode == STEAL_NORMAL || rt_task(task)) {
++	    if (task->prio >= pendowner->prio)
++		    return 0;
++    } else if (task->prio > pendowner->prio)
++	    return 0;
++    return 1;
++}
++
+ /*
+  * Try to take an rt-mutex
+  *
+@@ -748,8 +791,9 @@
+  * @waiter: The waiter that is queued to the lock's wait list if the
+  *	    callsite called task_blocked_on_lock(), otherwise NULL
+  */
+-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+-				struct rt_mutex_waiter *waiter)
++static int __try_to_take_rt_mutex(struct rt_mutex *lock,
++				  struct task_struct *task,
++				  struct rt_mutex_waiter *waiter, int mode)
+ {
+ 	unsigned long flags;
+ 
+@@ -788,8 +832,10 @@
+ 		 * If waiter is not the highest priority waiter of
+ 		 * @lock, give up.
+ 		 */
+-		if (waiter != rt_mutex_top_waiter(lock))
++		if (waiter != rt_mutex_top_waiter(lock)) {
++			/* XXX lock_is_stealable() ? */
+ 			return 0;
++		}
+ 
+ 		/*
+ 		 * We can acquire the lock. Remove the waiter from the
+@@ -807,14 +853,10 @@
+ 		 * not need to be dequeued.
+ 		 */
+ 		if (rt_mutex_has_waiters(lock)) {
+-			/*
+-			 * If @task->prio is greater than or equal to
+-			 * the top waiter priority (kernel view),
+-			 * @task lost.
+-			 */
+-			if (task->prio >= rt_mutex_top_waiter(lock)->prio)
+-				return 0;
++			struct task_struct *pown = rt_mutex_top_waiter(lock)->task;
+ 
++			if (task != pown && !lock_is_stealable(task, pown, mode))
++				return 0;
+ 			/*
+ 			 * The current top waiter stays enqueued. We
+ 			 * don't have to change anything in the lock
+@@ -863,6 +905,369 @@
+ 	return 1;
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * preemptible spin_lock functions:
++ */
++static inline void rt_spin_lock_fastlock(struct rt_mutex *lock,
++					 void  (*slowfn)(struct rt_mutex *lock))
++{
++	might_sleep();
++
++	if (likely(rt_mutex_cmpxchg(lock, NULL, current)))
++		rt_mutex_deadlock_account_lock(lock, current);
++	else
++		slowfn(lock);
++}
++
++static inline void rt_spin_lock_fastunlock(struct rt_mutex *lock,
++					   void  (*slowfn)(struct rt_mutex *lock))
++{
++	if (likely(rt_mutex_cmpxchg(lock, current, NULL)))
++		rt_mutex_deadlock_account_unlock(current);
++	else
++		slowfn(lock);
++}
++#ifdef CONFIG_SMP
++/*
++ * Note that owner is a speculative pointer and dereferencing relies
++ * on rcu_read_lock() and the check against the lock owner.
++ */
++static int adaptive_wait(struct rt_mutex *lock,
++			 struct task_struct *owner)
++{
++	int res = 0;
++
++	rcu_read_lock();
++	for (;;) {
++		if (owner != rt_mutex_owner(lock))
++			break;
++		/*
++		 * Ensure that owner->on_cpu is dereferenced _after_
++		 * checking the above to be valid.
++		 */
++		barrier();
++		if (!owner->on_cpu) {
++			res = 1;
++			break;
++		}
++		cpu_relax();
++	}
++	rcu_read_unlock();
++	return res;
++}
++#else
++static int adaptive_wait(struct rt_mutex *lock,
++			 struct task_struct *orig_owner)
++{
++	return 1;
++}
++#endif
++
++# define pi_lock(lock)		raw_spin_lock_irq(lock)
++# define pi_unlock(lock)	raw_spin_unlock_irq(lock)
++
++static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
++				   struct rt_mutex_waiter *waiter,
++				   struct task_struct *task,
++				   enum rtmutex_chainwalk chwalk);
++/*
++ * Slow path lock function spin_lock style: this variant is very
++ * careful not to miss any non-lock wakeups.
++ *
++ * We store the current state under p->pi_lock in p->saved_state and
++ * the try_to_wake_up() code handles this accordingly.
++ */
++static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
++{
++	struct task_struct *lock_owner, *self = current;
++	struct rt_mutex_waiter waiter, *top_waiter;
++	int ret;
++
++	rt_mutex_init_waiter(&waiter, true);
++
++	raw_spin_lock(&lock->wait_lock);
++
++	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL)) {
++		raw_spin_unlock(&lock->wait_lock);
++		return;
++	}
++
++	BUG_ON(rt_mutex_owner(lock) == self);
++
++	/*
++	 * We save whatever state the task is in and we'll restore it
++	 * after acquiring the lock taking real wakeups into account
++	 * as well. We are serialized via pi_lock against wakeups. See
++	 * try_to_wake_up().
++	 */
++	pi_lock(&self->pi_lock);
++	self->saved_state = self->state;
++	__set_current_state(TASK_UNINTERRUPTIBLE);
++	pi_unlock(&self->pi_lock);
++
++	ret = task_blocks_on_rt_mutex(lock, &waiter, self, 0);
++	BUG_ON(ret);
++
++	for (;;) {
++		/* Try to acquire the lock again. */
++		if (__try_to_take_rt_mutex(lock, self, &waiter, STEAL_LATERAL))
++			break;
++
++		top_waiter = rt_mutex_top_waiter(lock);
++		lock_owner = rt_mutex_owner(lock);
++
++		raw_spin_unlock(&lock->wait_lock);
++
++		debug_rt_mutex_print_deadlock(&waiter);
++
++		if (top_waiter != &waiter || adaptive_wait(lock, lock_owner))
++			schedule_rt_mutex(lock);
++
++		raw_spin_lock(&lock->wait_lock);
++
++		pi_lock(&self->pi_lock);
++		__set_current_state(TASK_UNINTERRUPTIBLE);
++		pi_unlock(&self->pi_lock);
++	}
++
++	/*
++	 * Restore the task state to current->saved_state. We set it
++	 * to the original state above and the try_to_wake_up() code
++	 * has possibly updated it when a real (non-rtmutex) wakeup
++	 * happened while we were blocked. Clear saved_state so
++	 * try_to_wakeup() does not get confused.
++	 */
++	pi_lock(&self->pi_lock);
++	__set_current_state(self->saved_state);
++	self->saved_state = TASK_RUNNING;
++	pi_unlock(&self->pi_lock);
++
++	/*
++	 * try_to_take_rt_mutex() sets the waiter bit
++	 * unconditionally. We might have to fix that up:
++	 */
++	fixup_rt_mutex_waiters(lock);
++
++	BUG_ON(rt_mutex_has_waiters(lock) && &waiter == rt_mutex_top_waiter(lock));
++	BUG_ON(!RB_EMPTY_NODE(&waiter.tree_entry));
++
++	raw_spin_unlock(&lock->wait_lock);
++
++	debug_rt_mutex_free_waiter(&waiter);
++}
++
++static void wakeup_next_waiter(struct rt_mutex *lock);
++/*
++ * Slow path to release a rt_mutex spin_lock style
++ */
++static void __sched __rt_spin_lock_slowunlock(struct rt_mutex *lock)
++{
++	debug_rt_mutex_unlock(lock);
++
++	rt_mutex_deadlock_account_unlock(current);
++
++	if (!rt_mutex_has_waiters(lock)) {
++		lock->owner = NULL;
++		raw_spin_unlock(&lock->wait_lock);
++		return;
++	}
++
++	wakeup_next_waiter(lock);
++
++	raw_spin_unlock(&lock->wait_lock);
++
++	/* Undo pi boosting.when necessary */
++	rt_mutex_adjust_prio(current);
++}
++
++static void  noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
++{
++	raw_spin_lock(&lock->wait_lock);
++	__rt_spin_lock_slowunlock(lock);
++}
++
++static void  noinline __sched rt_spin_lock_slowunlock_hirq(struct rt_mutex *lock)
++{
++	int ret;
++
++	do {
++		ret = raw_spin_trylock(&lock->wait_lock);
++	} while (!ret);
++
++	__rt_spin_lock_slowunlock(lock);
++}
++
++void __lockfunc rt_spin_lock(spinlock_t *lock)
++{
++	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++}
++EXPORT_SYMBOL(rt_spin_lock);
++
++void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
++{
++	rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
++}
++EXPORT_SYMBOL(__rt_spin_lock);
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
++{
++	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
++}
++EXPORT_SYMBOL(rt_spin_lock_nested);
++#endif
++
++void __lockfunc rt_spin_unlock(spinlock_t *lock)
++{
++	/* NOTE: we always pass in '1' for nested, for simplicity */
++	spin_release(&lock->dep_map, 1, _RET_IP_);
++	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
++}
++EXPORT_SYMBOL(rt_spin_unlock);
++
++void __lockfunc rt_spin_unlock_after_trylock_in_irq(spinlock_t *lock)
++{
++	/* NOTE: we always pass in '1' for nested, for simplicity */
++	spin_release(&lock->dep_map, 1, _RET_IP_);
++	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock_hirq);
++}
++
++void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
++{
++	rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
++}
++EXPORT_SYMBOL(__rt_spin_unlock);
++
++/*
++ * Wait for the lock to get unlocked: instead of polling for an unlock
++ * (like raw spinlocks do), we lock and unlock, to force the kernel to
++ * schedule if there's contention:
++ */
++void __lockfunc rt_spin_unlock_wait(spinlock_t *lock)
++{
++	spin_lock(lock);
++	spin_unlock(lock);
++}
++EXPORT_SYMBOL(rt_spin_unlock_wait);
++
++int __lockfunc __rt_spin_trylock(struct rt_mutex *lock)
++{
++	return rt_mutex_trylock(lock);
++}
++
++int __lockfunc rt_spin_trylock(spinlock_t *lock)
++{
++	int ret = rt_mutex_trylock(&lock->lock);
++
++	if (ret)
++		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(rt_spin_trylock);
++
++int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
++{
++	int ret;
++
++	local_bh_disable();
++	ret = rt_mutex_trylock(&lock->lock);
++	if (ret) {
++		migrate_disable();
++		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++	} else
++		local_bh_enable();
++	return ret;
++}
++EXPORT_SYMBOL(rt_spin_trylock_bh);
++
++int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags)
++{
++	int ret;
++
++	*flags = 0;
++	ret = rt_mutex_trylock(&lock->lock);
++	if (ret) {
++		migrate_disable();
++		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++	}
++	return ret;
++}
++EXPORT_SYMBOL(rt_spin_trylock_irqsave);
++
++int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock)
++{
++	/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
++	if (atomic_add_unless(atomic, -1, 1))
++		return 0;
++	migrate_disable();
++	rt_spin_lock(lock);
++	if (atomic_dec_and_test(atomic))
++		return 1;
++	rt_spin_unlock(lock);
++	migrate_enable();
++	return 0;
++}
++EXPORT_SYMBOL(atomic_dec_and_spin_lock);
++
++	void
++__rt_spin_lock_init(spinlock_t *lock, char *name, struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held lock:
++	 */
++	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
++	lockdep_init_map(&lock->dep_map, name, key, 0);
++#endif
++}
++EXPORT_SYMBOL(__rt_spin_lock_init);
++
++#endif /* PREEMPT_RT_FULL */
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++	static inline int __sched
++__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
++	struct ww_acquire_ctx *hold_ctx = ACCESS_ONCE(ww->ctx);
++
++	if (!hold_ctx)
++		return 0;
++
++	if (unlikely(ctx == hold_ctx))
++		return -EALREADY;
++
++	if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
++	    (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
++#ifdef CONFIG_DEBUG_MUTEXES
++		DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
++		ctx->contending_lock = ww;
++#endif
++		return -EDEADLK;
++	}
++
++	return 0;
++}
++#else
++	static inline int __sched
++__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++	BUG();
++	return 0;
++}
++
++#endif
++
++static inline int
++try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
++		     struct rt_mutex_waiter *waiter)
++{
++	return __try_to_take_rt_mutex(lock, task, waiter, STEAL_NORMAL);
++}
++
+ /*
+  * Task blocks on lock.
+  *
+@@ -894,6 +1299,23 @@
+ 		return -EDEADLK;
+ 
+ 	raw_spin_lock_irqsave(&task->pi_lock, flags);
++
++	/*
++	 * In the case of futex requeue PI, this will be a proxy
++	 * lock. The task will wake unaware that it is enqueueed on
++	 * this lock. Avoid blocking on two locks and corrupting
++	 * pi_blocked_on via the PI_WAKEUP_INPROGRESS
++	 * flag. futex_wait_requeue_pi() sets this when it wakes up
++	 * before requeue (due to a signal or timeout). Do not enqueue
++	 * the task if PI_WAKEUP_INPROGRESS is set.
++	 */
++	if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
++		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
++		return -EAGAIN;
++	}
++
++	BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
++
+ 	__rt_mutex_adjust_prio(task);
+ 	waiter->task = task;
+ 	waiter->lock = lock;
+@@ -917,7 +1339,7 @@
+ 		rt_mutex_enqueue_pi(owner, waiter);
+ 
+ 		__rt_mutex_adjust_prio(owner);
+-		if (owner->pi_blocked_on)
++		if (rt_mutex_real_waiter(owner->pi_blocked_on))
+ 			chain_walk = 1;
+ 	} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
+ 		chain_walk = 1;
+@@ -994,7 +1416,7 @@
+ 	 * long as we hold lock->wait_lock. The waiter task needs to
+ 	 * acquire it in order to dequeue the waiter.
+ 	 */
+-	wake_up_process(waiter->task);
++	rt_mutex_wake_waiter(waiter);
+ }
+ 
+ /*
+@@ -1008,7 +1430,7 @@
+ {
+ 	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
+ 	struct task_struct *owner = rt_mutex_owner(lock);
+-	struct rt_mutex *next_lock;
++	struct rt_mutex *next_lock = NULL;
+ 	unsigned long flags;
+ 
+ 	raw_spin_lock_irqsave(&current->pi_lock, flags);
+@@ -1033,7 +1455,8 @@
+ 	__rt_mutex_adjust_prio(owner);
+ 
+ 	/* Store the lock on which owner is blocked or NULL */
+-	next_lock = task_blocked_on_lock(owner);
++	if (rt_mutex_real_waiter(owner->pi_blocked_on))
++		next_lock = task_blocked_on_lock(owner);
+ 
+ 	raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+ 
+@@ -1069,17 +1492,17 @@
+ 	raw_spin_lock_irqsave(&task->pi_lock, flags);
+ 
+ 	waiter = task->pi_blocked_on;
+-	if (!waiter || (waiter->prio == task->prio &&
++	if (!rt_mutex_real_waiter(waiter) || (waiter->prio == task->prio &&
+ 			!dl_prio(task->prio))) {
+ 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 		return;
+ 	}
+ 	next_lock = waiter->lock;
+-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 
+ 	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+ 	get_task_struct(task);
+ 
++	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
+ 				   next_lock, NULL, task);
+ }
+@@ -1097,7 +1520,8 @@
+ static int __sched
+ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 		    struct hrtimer_sleeper *timeout,
+-		    struct rt_mutex_waiter *waiter)
++		    struct rt_mutex_waiter *waiter,
++		    struct ww_acquire_ctx *ww_ctx)
+ {
+ 	int ret = 0;
+ 
+@@ -1120,6 +1544,12 @@
+ 				break;
+ 		}
+ 
++		if (ww_ctx && ww_ctx->acquired > 0) {
++			ret = __mutex_lock_check_stamp(lock, ww_ctx);
++			if (ret)
++				break;
++		}
++
+ 		raw_spin_unlock(&lock->wait_lock);
+ 
+ 		debug_rt_mutex_print_deadlock(waiter);
+@@ -1153,25 +1583,102 @@
+ 	}
+ }
+ 
++static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
++						   struct ww_acquire_ctx *ww_ctx)
++{
++#ifdef CONFIG_DEBUG_MUTEXES
++	/*
++	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
++	 * but released with a normal mutex_unlock in this call.
++	 *
++	 * This should never happen, always use ww_mutex_unlock.
++	 */
++	DEBUG_LOCKS_WARN_ON(ww->ctx);
++
++	/*
++	 * Not quite done after calling ww_acquire_done() ?
++	 */
++	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
++
++	if (ww_ctx->contending_lock) {
++		/*
++		 * After -EDEADLK you tried to
++		 * acquire a different ww_mutex? Bad!
++		 */
++		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
++
++		/*
++		 * You called ww_mutex_lock after receiving -EDEADLK,
++		 * but 'forgot' to unlock everything else first?
++		 */
++		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
++		ww_ctx->contending_lock = NULL;
++	}
++
++	/*
++	 * Naughty, using a different class will lead to undefined behavior!
++	 */
++	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
++#endif
++	ww_ctx->acquired++;
++}
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++static void ww_mutex_account_lock(struct rt_mutex *lock,
++				  struct ww_acquire_ctx *ww_ctx)
++{
++	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
++	struct rt_mutex_waiter *waiter, *n;
++
++	/*
++	 * This branch gets optimized out for the common case,
++	 * and is only important for ww_mutex_lock.
++	 */
++	ww_mutex_lock_acquired(ww, ww_ctx);
++	ww->ctx = ww_ctx;
++
++	/*
++	 * Give any possible sleeping processes the chance to wake up,
++	 * so they can recheck if they have to back off.
++	 */
++	rbtree_postorder_for_each_entry_safe(waiter, n, &lock->waiters,
++					     tree_entry) {
++		/* XXX debug rt mutex waiter wakeup */
++
++		BUG_ON(waiter->lock != lock);
++		rt_mutex_wake_waiter(waiter);
++	}
++}
++
++#else
++
++static void ww_mutex_account_lock(struct rt_mutex *lock,
++				  struct ww_acquire_ctx *ww_ctx)
++{
++	BUG();
++}
++#endif
++
+ /*
+  * Slow path lock function:
+  */
+ static int __sched
+ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 		  struct hrtimer_sleeper *timeout,
+-		  enum rtmutex_chainwalk chwalk)
++		  enum rtmutex_chainwalk chwalk,
++		  struct ww_acquire_ctx *ww_ctx)
+ {
+ 	struct rt_mutex_waiter waiter;
+ 	int ret = 0;
+ 
+-	debug_rt_mutex_init_waiter(&waiter);
+-	RB_CLEAR_NODE(&waiter.pi_tree_entry);
+-	RB_CLEAR_NODE(&waiter.tree_entry);
++	rt_mutex_init_waiter(&waiter, false);
+ 
+ 	raw_spin_lock(&lock->wait_lock);
+ 
+ 	/* Try to acquire the lock again: */
+ 	if (try_to_take_rt_mutex(lock, current, NULL)) {
++		if (ww_ctx)
++			ww_mutex_account_lock(lock, ww_ctx);
+ 		raw_spin_unlock(&lock->wait_lock);
+ 		return 0;
+ 	}
+@@ -1188,13 +1695,17 @@
+ 	ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk);
+ 
+ 	if (likely(!ret))
+-		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
++		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter,
++					  ww_ctx);
+ 
+ 	set_current_state(TASK_RUNNING);
+ 
+ 	if (unlikely(ret)) {
+-		remove_waiter(lock, &waiter);
++		if (rt_mutex_has_waiters(lock))
++			remove_waiter(lock, &waiter);
+ 		rt_mutex_handle_deadlock(ret, chwalk, &waiter);
++	} else if (ww_ctx) {
++		ww_mutex_account_lock(lock, ww_ctx);
+ 	}
+ 
+ 	/*
+@@ -1233,7 +1744,8 @@
+ 	 * The mutex has currently no owner. Lock the wait lock and
+ 	 * try to acquire the lock.
+ 	 */
+-	raw_spin_lock(&lock->wait_lock);
++	if (!raw_spin_trylock(&lock->wait_lock))
++		return 0;
+ 
+ 	ret = try_to_take_rt_mutex(lock, current, NULL);
+ 
+@@ -1319,31 +1831,36 @@
+  */
+ static inline int
+ rt_mutex_fastlock(struct rt_mutex *lock, int state,
++		  struct ww_acquire_ctx *ww_ctx,
+ 		  int (*slowfn)(struct rt_mutex *lock, int state,
+ 				struct hrtimer_sleeper *timeout,
+-				enum rtmutex_chainwalk chwalk))
++				enum rtmutex_chainwalk chwalk,
++				struct ww_acquire_ctx *ww_ctx))
+ {
+ 	if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ 		rt_mutex_deadlock_account_lock(lock, current);
+ 		return 0;
+ 	} else
+-		return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
++		return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK,
++			      ww_ctx);
+ }
+ 
+ static inline int
+ rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
+ 			struct hrtimer_sleeper *timeout,
+ 			enum rtmutex_chainwalk chwalk,
++			struct ww_acquire_ctx *ww_ctx,
+ 			int (*slowfn)(struct rt_mutex *lock, int state,
+ 				      struct hrtimer_sleeper *timeout,
+-				      enum rtmutex_chainwalk chwalk))
++				      enum rtmutex_chainwalk chwalk,
++				      struct ww_acquire_ctx *ww_ctx))
+ {
+ 	if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
+ 	    likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+ 		rt_mutex_deadlock_account_lock(lock, current);
+ 		return 0;
+ 	} else
+-		return slowfn(lock, state, timeout, chwalk);
++		return slowfn(lock, state, timeout, chwalk, ww_ctx);
+ }
+ 
+ static inline int
+@@ -1376,7 +1893,7 @@
+ {
+ 	might_sleep();
+ 
+-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
++	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, NULL, rt_mutex_slowlock);
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_lock);
+ 
+@@ -1393,7 +1910,7 @@
+ {
+ 	might_sleep();
+ 
+-	return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, rt_mutex_slowlock);
++	return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, NULL, rt_mutex_slowlock);
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
+ 
+@@ -1406,11 +1923,30 @@
+ 	might_sleep();
+ 
+ 	return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
+-				       RT_MUTEX_FULL_CHAINWALK,
++				       RT_MUTEX_FULL_CHAINWALK, NULL,
+ 				       rt_mutex_slowlock);
+ }
+ 
+ /**
++ * rt_mutex_lock_killable - lock a rt_mutex killable
++ *
++ * @lock:              the rt_mutex to be locked
++ * @detect_deadlock:   deadlock detection on/off
++ *
++ * Returns:
++ *  0          on success
++ * -EINTR      when interrupted by a signal
++ * -EDEADLK    when the lock would deadlock (when deadlock detection is on)
++ */
++int __sched rt_mutex_lock_killable(struct rt_mutex *lock)
++{
++	might_sleep();
++
++	return rt_mutex_fastlock(lock, TASK_KILLABLE, NULL, rt_mutex_slowlock);
++}
++EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
++
++/**
+  * rt_mutex_timed_lock - lock a rt_mutex interruptible
+  *			the timeout structure is provided
+  *			by the caller
+@@ -1430,6 +1966,7 @@
+ 
+ 	return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
+ 				       RT_MUTEX_MIN_CHAINWALK,
++				       NULL,
+ 				       rt_mutex_slowlock);
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
+@@ -1488,13 +2025,12 @@
+ void __rt_mutex_init(struct rt_mutex *lock, const char *name)
+ {
+ 	lock->owner = NULL;
+-	raw_spin_lock_init(&lock->wait_lock);
+ 	lock->waiters = RB_ROOT;
+ 	lock->waiters_leftmost = NULL;
+ 
+ 	debug_rt_mutex_init(lock, name);
+ }
+-EXPORT_SYMBOL_GPL(__rt_mutex_init);
++EXPORT_SYMBOL(__rt_mutex_init);
+ 
+ /**
+  * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
+@@ -1509,7 +2045,7 @@
+ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ 				struct task_struct *proxy_owner)
+ {
+-	__rt_mutex_init(lock, NULL);
++	rt_mutex_init(lock);
+ 	debug_rt_mutex_proxy_lock(lock, proxy_owner);
+ 	rt_mutex_set_owner(lock, proxy_owner);
+ 	rt_mutex_deadlock_account_lock(lock, proxy_owner);
+@@ -1557,6 +2093,35 @@
+ 		return 1;
+ 	}
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++	/*
++	 * In PREEMPT_RT there's an added race.
++	 * If the task, that we are about to requeue, times out,
++	 * it can set the PI_WAKEUP_INPROGRESS. This tells the requeue
++	 * to skip this task. But right after the task sets
++	 * its pi_blocked_on to PI_WAKEUP_INPROGRESS it can then
++	 * block on the spin_lock(&hb->lock), which in RT is an rtmutex.
++	 * This will replace the PI_WAKEUP_INPROGRESS with the actual
++	 * lock that it blocks on. We *must not* place this task
++	 * on this proxy lock in that case.
++	 *
++	 * To prevent this race, we first take the task's pi_lock
++	 * and check if it has updated its pi_blocked_on. If it has,
++	 * we assume that it woke up and we return -EAGAIN.
++	 * Otherwise, we set the task's pi_blocked_on to
++	 * PI_REQUEUE_INPROGRESS, so that if the task is waking up
++	 * it will know that we are in the process of requeuing it.
++	 */
++	raw_spin_lock_irq(&task->pi_lock);
++	if (task->pi_blocked_on) {
++		raw_spin_unlock_irq(&task->pi_lock);
++		raw_spin_unlock(&lock->wait_lock);
++		return -EAGAIN;
++	}
++	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
++	raw_spin_unlock_irq(&task->pi_lock);
++#endif
++
+ 	/* We enforce deadlock detection for futexes */
+ 	ret = task_blocks_on_rt_mutex(lock, waiter, task,
+ 				      RT_MUTEX_FULL_CHAINWALK);
+@@ -1626,7 +2191,7 @@
+ 
+ 	set_current_state(TASK_INTERRUPTIBLE);
+ 
+-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
++	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL);
+ 
+ 	set_current_state(TASK_RUNNING);
+ 
+@@ -1643,3 +2208,89 @@
+ 
+ 	return ret;
+ }
++
++static inline int
++ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
++	unsigned tmp;
++
++	if (ctx->deadlock_inject_countdown-- == 0) {
++		tmp = ctx->deadlock_inject_interval;
++		if (tmp > UINT_MAX/4)
++			tmp = UINT_MAX;
++		else
++			tmp = tmp*2 + tmp + tmp/2;
++
++		ctx->deadlock_inject_interval = tmp;
++		ctx->deadlock_inject_countdown = tmp;
++		ctx->contending_lock = lock;
++
++		ww_mutex_unlock(lock);
++
++		return -EDEADLK;
++	}
++#endif
++
++	return 0;
++}
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++int __sched
++__ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
++{
++	int ret;
++
++	might_sleep();
++
++	mutex_acquire_nest(&lock->base.dep_map, 0, 0, &ww_ctx->dep_map, _RET_IP_);
++	ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL,
++				RT_MUTEX_FULL_CHAINWALK, ww_ctx);
++	if (ret)
++		mutex_release(&lock->base.dep_map, 1, _RET_IP_);
++	else if (!ret && ww_ctx->acquired > 1)
++		return ww_mutex_deadlock_injection(lock, ww_ctx);
++
++	return ret;
++}
++EXPORT_SYMBOL_GPL(__ww_mutex_lock_interruptible);
++
++int __sched
++__ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx)
++{
++	int ret;
++
++	might_sleep();
++
++	mutex_acquire_nest(&lock->base.dep_map, 0, 0, &ww_ctx->dep_map, _RET_IP_);
++	ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL,
++				RT_MUTEX_FULL_CHAINWALK, ww_ctx);
++	if (ret)
++		mutex_release(&lock->base.dep_map, 1, _RET_IP_);
++	else if (!ret && ww_ctx->acquired > 1)
++		return ww_mutex_deadlock_injection(lock, ww_ctx);
++
++	return ret;
++}
++EXPORT_SYMBOL_GPL(__ww_mutex_lock);
++
++void __sched ww_mutex_unlock(struct ww_mutex *lock)
++{
++	/*
++	 * The unlocking fastpath is the 0->1 transition from 'locked'
++	 * into 'unlocked' state:
++	 */
++	if (lock->ctx) {
++#ifdef CONFIG_DEBUG_MUTEXES
++		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
++#endif
++		if (lock->ctx->acquired > 0)
++			lock->ctx->acquired--;
++		lock->ctx = NULL;
++	}
++
++	mutex_release(&lock->base.dep_map, 1, _RET_IP_);
++	rt_mutex_unlock(&lock->base.lock);
++}
++EXPORT_SYMBOL(ww_mutex_unlock);
++#endif
+diff -Nur linux-3.18.8.orig/kernel/locking/rtmutex_common.h linux-3.18.8/kernel/locking/rtmutex_common.h
+--- linux-3.18.8.orig/kernel/locking/rtmutex_common.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/rtmutex_common.h	2015-03-03 08:05:18.000000000 +0100
+@@ -49,6 +49,7 @@
+ 	struct rb_node          pi_tree_entry;
+ 	struct task_struct	*task;
+ 	struct rt_mutex		*lock;
++	bool			savestate;
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+ 	unsigned long		ip;
+ 	struct pid		*deadlock_task_pid;
+@@ -119,6 +120,9 @@
+ /*
+  * PI-futex support (proxy locking functions, etc.):
+  */
++#define PI_WAKEUP_INPROGRESS	((struct rt_mutex_waiter *) 1)
++#define PI_REQUEUE_INPROGRESS	((struct rt_mutex_waiter *) 2)
++
+ extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
+ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ 				       struct task_struct *proxy_owner);
+@@ -138,4 +142,14 @@
+ # include "rtmutex.h"
+ #endif
+ 
++static inline void
++rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
++{
++	debug_rt_mutex_init_waiter(waiter);
++	waiter->task = NULL;
++	waiter->savestate = savestate;
++	RB_CLEAR_NODE(&waiter->pi_tree_entry);
++	RB_CLEAR_NODE(&waiter->tree_entry);
++}
++
+ #endif
+diff -Nur linux-3.18.8.orig/kernel/locking/spinlock.c linux-3.18.8/kernel/locking/spinlock.c
+--- linux-3.18.8.orig/kernel/locking/spinlock.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/spinlock.c	2015-03-03 08:05:18.000000000 +0100
+@@ -124,8 +124,11 @@
+  *         __[spin|read|write]_lock_bh()
+  */
+ BUILD_LOCK_OPS(spin, raw_spinlock);
++
++#ifndef CONFIG_PREEMPT_RT_FULL
+ BUILD_LOCK_OPS(read, rwlock);
+ BUILD_LOCK_OPS(write, rwlock);
++#endif
+ 
+ #endif
+ 
+@@ -209,6 +212,8 @@
+ EXPORT_SYMBOL(_raw_spin_unlock_bh);
+ #endif
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++
+ #ifndef CONFIG_INLINE_READ_TRYLOCK
+ int __lockfunc _raw_read_trylock(rwlock_t *lock)
+ {
+@@ -353,6 +358,8 @@
+ EXPORT_SYMBOL(_raw_write_unlock_bh);
+ #endif
+ 
++#endif /* !PREEMPT_RT_FULL */
++
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 
+ void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
+diff -Nur linux-3.18.8.orig/kernel/locking/spinlock_debug.c linux-3.18.8/kernel/locking/spinlock_debug.c
+--- linux-3.18.8.orig/kernel/locking/spinlock_debug.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/locking/spinlock_debug.c	2015-03-03 08:05:18.000000000 +0100
+@@ -31,6 +31,7 @@
+ 
+ EXPORT_SYMBOL(__raw_spin_lock_init);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ void __rwlock_init(rwlock_t *lock, const char *name,
+ 		   struct lock_class_key *key)
+ {
+@@ -48,6 +49,7 @@
+ }
+ 
+ EXPORT_SYMBOL(__rwlock_init);
++#endif
+ 
+ static void spin_dump(raw_spinlock_t *lock, const char *msg)
+ {
+@@ -159,6 +161,7 @@
+ 	arch_spin_unlock(&lock->raw_lock);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ static void rwlock_bug(rwlock_t *lock, const char *msg)
+ {
+ 	if (!debug_locks_off())
+@@ -300,3 +303,5 @@
+ 	debug_write_unlock(lock);
+ 	arch_write_unlock(&lock->raw_lock);
+ }
++
++#endif
+diff -Nur linux-3.18.8.orig/kernel/panic.c linux-3.18.8/kernel/panic.c
+--- linux-3.18.8.orig/kernel/panic.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/panic.c	2015-03-03 08:05:18.000000000 +0100
+@@ -384,9 +384,11 @@
+ 
+ static int init_oops_id(void)
+ {
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	if (!oops_id)
+ 		get_random_bytes(&oops_id, sizeof(oops_id));
+ 	else
++#endif
+ 		oops_id++;
+ 
+ 	return 0;
+diff -Nur linux-3.18.8.orig/kernel/power/hibernate.c linux-3.18.8/kernel/power/hibernate.c
+--- linux-3.18.8.orig/kernel/power/hibernate.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/power/hibernate.c	2015-03-03 08:05:18.000000000 +0100
+@@ -287,6 +287,8 @@
+ 
+ 	local_irq_disable();
+ 
++	system_state = SYSTEM_SUSPEND;
++
+ 	error = syscore_suspend();
+ 	if (error) {
+ 		printk(KERN_ERR "PM: Some system devices failed to power down, "
+@@ -316,6 +318,7 @@
+ 	syscore_resume();
+ 
+  Enable_irqs:
++	system_state = SYSTEM_RUNNING;
+ 	local_irq_enable();
+ 
+  Enable_cpus:
+@@ -439,6 +442,7 @@
+ 		goto Enable_cpus;
+ 
+ 	local_irq_disable();
++	system_state = SYSTEM_SUSPEND;
+ 
+ 	error = syscore_suspend();
+ 	if (error)
+@@ -472,6 +476,7 @@
+ 	syscore_resume();
+ 
+  Enable_irqs:
++	system_state = SYSTEM_RUNNING;
+ 	local_irq_enable();
+ 
+  Enable_cpus:
+@@ -557,6 +562,7 @@
+ 		goto Platform_finish;
+ 
+ 	local_irq_disable();
++	system_state = SYSTEM_SUSPEND;
+ 	syscore_suspend();
+ 	if (pm_wakeup_pending()) {
+ 		error = -EAGAIN;
+@@ -569,6 +575,7 @@
+ 
+  Power_up:
+ 	syscore_resume();
++	system_state = SYSTEM_RUNNING;
+ 	local_irq_enable();
+ 	enable_nonboot_cpus();
+ 
+diff -Nur linux-3.18.8.orig/kernel/power/suspend.c linux-3.18.8/kernel/power/suspend.c
+--- linux-3.18.8.orig/kernel/power/suspend.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/power/suspend.c	2015-03-03 08:05:18.000000000 +0100
+@@ -318,6 +318,8 @@
+ 	arch_suspend_disable_irqs();
+ 	BUG_ON(!irqs_disabled());
+ 
++	system_state = SYSTEM_SUSPEND;
++
+ 	error = syscore_suspend();
+ 	if (!error) {
+ 		*wakeup = pm_wakeup_pending();
+@@ -332,6 +334,8 @@
+ 		syscore_resume();
+ 	}
+ 
++	system_state = SYSTEM_RUNNING;
++
+ 	arch_suspend_enable_irqs();
+ 	BUG_ON(irqs_disabled());
+ 
+diff -Nur linux-3.18.8.orig/kernel/printk/printk.c linux-3.18.8/kernel/printk/printk.c
+--- linux-3.18.8.orig/kernel/printk/printk.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/printk/printk.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1165,6 +1165,7 @@
+ {
+ 	char *text;
+ 	int len = 0;
++	int attempts = 0;
+ 
+ 	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
+ 	if (!text)
+@@ -1176,7 +1177,14 @@
+ 		u64 seq;
+ 		u32 idx;
+ 		enum log_flags prev;
+-
++		int num_msg;
++try_again:
++		attempts++;
++		if (attempts > 10) {
++			len = -EBUSY;
++			goto out;
++		}
++		num_msg = 0;
+ 		if (clear_seq < log_first_seq) {
+ 			/* messages are gone, move to first available one */
+ 			clear_seq = log_first_seq;
+@@ -1197,6 +1205,14 @@
+ 			prev = msg->flags;
+ 			idx = log_next(idx);
+ 			seq++;
++			num_msg++;
++			if (num_msg > 5) {
++				num_msg = 0;
++				raw_spin_unlock_irq(&logbuf_lock);
++				raw_spin_lock_irq(&logbuf_lock);
++				if (clear_seq < log_first_seq)
++					goto try_again;
++			}
+ 		}
+ 
+ 		/* move first record forward until length fits into the buffer */
+@@ -1210,6 +1226,14 @@
+ 			prev = msg->flags;
+ 			idx = log_next(idx);
+ 			seq++;
++			num_msg++;
++			if (num_msg > 5) {
++				num_msg = 0;
++				raw_spin_unlock_irq(&logbuf_lock);
++				raw_spin_lock_irq(&logbuf_lock);
++				if (clear_seq < log_first_seq)
++					goto try_again;
++			}
+ 		}
+ 
+ 		/* last message fitting into this dump */
+@@ -1250,6 +1274,7 @@
+ 		clear_seq = log_next_seq;
+ 		clear_idx = log_next_idx;
+ 	}
++out:
+ 	raw_spin_unlock_irq(&logbuf_lock);
+ 
+ 	kfree(text);
+@@ -1407,6 +1432,7 @@
+ 	if (!console_drivers)
+ 		return;
+ 
++	migrate_disable();
+ 	for_each_console(con) {
+ 		if (exclusive_console && con != exclusive_console)
+ 			continue;
+@@ -1419,6 +1445,7 @@
+ 			continue;
+ 		con->write(con, text, len);
+ 	}
++	migrate_enable();
+ }
+ 
+ /*
+@@ -1479,6 +1506,15 @@
+ static int console_trylock_for_printk(void)
+ {
+ 	unsigned int cpu = smp_processor_id();
++#ifdef CONFIG_PREEMPT_RT_FULL
++	int lock = !early_boot_irqs_disabled && (preempt_count() == 0) &&
++		!irqs_disabled();
++#else
++	int lock = 1;
++#endif
++
++	if (!lock)
++		return 0;
+ 
+ 	if (!console_trylock())
+ 		return 0;
+@@ -1613,6 +1649,62 @@
+ 	return textlen;
+ }
+ 
++#ifdef CONFIG_EARLY_PRINTK
++struct console *early_console;
++
++void early_vprintk(const char *fmt, va_list ap)
++{
++	if (early_console) {
++		char buf[512];
++		int n = vscnprintf(buf, sizeof(buf), fmt, ap);
++
++		early_console->write(early_console, buf, n);
++	}
++}
++
++asmlinkage void early_printk(const char *fmt, ...)
++{
++	va_list ap;
++
++	va_start(ap, fmt);
++	early_vprintk(fmt, ap);
++	va_end(ap);
++}
++
++/*
++ * This is independent of any log levels - a global
++ * kill switch that turns off all of printk.
++ *
++ * Used by the NMI watchdog if early-printk is enabled.
++ */
++static bool __read_mostly printk_killswitch;
++
++static int __init force_early_printk_setup(char *str)
++{
++	printk_killswitch = true;
++	return 0;
++}
++early_param("force_early_printk", force_early_printk_setup);
++
++void printk_kill(void)
++{
++	printk_killswitch = true;
++}
++
++static int forced_early_printk(const char *fmt, va_list ap)
++{
++	if (!printk_killswitch)
++		return 0;
++	early_vprintk(fmt, ap);
++	return 1;
++}
++#else
++static inline int forced_early_printk(const char *fmt, va_list ap)
++{
++	return 0;
++}
++#endif
++
+ asmlinkage int vprintk_emit(int facility, int level,
+ 			    const char *dict, size_t dictlen,
+ 			    const char *fmt, va_list args)
+@@ -1629,6 +1721,13 @@
+ 	/* cpu currently holding logbuf_lock in this function */
+ 	static volatile unsigned int logbuf_cpu = UINT_MAX;
+ 
++	/*
++	 * Fall back to early_printk if a debugging subsystem has
++	 * killed printk output
++	 */
++	if (unlikely(forced_early_printk(fmt, args)))
++		return 1;
++
+ 	if (level == SCHED_MESSAGE_LOGLEVEL) {
+ 		level = -1;
+ 		in_sched = true;
+@@ -1769,8 +1868,7 @@
+ 		 * console_sem which would prevent anyone from printing to
+ 		 * console
+ 		 */
+-		preempt_disable();
+-
++		migrate_disable();
+ 		/*
+ 		 * Try to acquire and then immediately release the console
+ 		 * semaphore.  The release will print out buffers and wake up
+@@ -1778,7 +1876,7 @@
+ 		 */
+ 		if (console_trylock_for_printk())
+ 			console_unlock();
+-		preempt_enable();
++		migrate_enable();
+ 		lockdep_on();
+ 	}
+ 
+@@ -1878,29 +1976,6 @@
+ 
+ #endif /* CONFIG_PRINTK */
+ 
+-#ifdef CONFIG_EARLY_PRINTK
+-struct console *early_console;
+-
+-void early_vprintk(const char *fmt, va_list ap)
+-{
+-	if (early_console) {
+-		char buf[512];
+-		int n = vscnprintf(buf, sizeof(buf), fmt, ap);
+-
+-		early_console->write(early_console, buf, n);
+-	}
+-}
+-
+-asmlinkage __visible void early_printk(const char *fmt, ...)
+-{
+-	va_list ap;
+-
+-	va_start(ap, fmt);
+-	early_vprintk(fmt, ap);
+-	va_end(ap);
+-}
+-#endif
+-
+ static int __add_preferred_console(char *name, int idx, char *options,
+ 				   char *brl_options)
+ {
+@@ -2140,11 +2215,16 @@
+ 		goto out;
+ 
+ 	len = cont_print_text(text, size);
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	raw_spin_unlock(&logbuf_lock);
+ 	stop_critical_timings();
+ 	call_console_drivers(cont.level, text, len);
+ 	start_critical_timings();
+ 	local_irq_restore(flags);
++#else
++	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
++	call_console_drivers(cont.level, text, len);
++#endif
+ 	return;
+ out:
+ 	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+@@ -2232,12 +2312,17 @@
+ 		console_idx = log_next(console_idx);
+ 		console_seq++;
+ 		console_prev = msg->flags;
++#ifdef CONFIG_PREEMPT_RT_FULL
++		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
++		call_console_drivers(level, text, len);
++#else
+ 		raw_spin_unlock(&logbuf_lock);
+ 
+ 		stop_critical_timings();	/* don't trace print latency */
+ 		call_console_drivers(level, text, len);
+ 		start_critical_timings();
+ 		local_irq_restore(flags);
++#endif
+ 	}
+ 	console_locked = 0;
+ 
+diff -Nur linux-3.18.8.orig/kernel/ptrace.c linux-3.18.8/kernel/ptrace.c
+--- linux-3.18.8.orig/kernel/ptrace.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/ptrace.c	2015-03-03 08:05:18.000000000 +0100
+@@ -129,7 +129,12 @@
+ 
+ 	spin_lock_irq(&task->sighand->siglock);
+ 	if (task_is_traced(task) && !__fatal_signal_pending(task)) {
+-		task->state = __TASK_TRACED;
++		raw_spin_lock_irq(&task->pi_lock);
++		if (task->state & __TASK_TRACED)
++			task->state = __TASK_TRACED;
++		else
++			task->saved_state = __TASK_TRACED;
++		raw_spin_unlock_irq(&task->pi_lock);
+ 		ret = true;
+ 	}
+ 	spin_unlock_irq(&task->sighand->siglock);
+diff -Nur linux-3.18.8.orig/kernel/rcu/tiny.c linux-3.18.8/kernel/rcu/tiny.c
+--- linux-3.18.8.orig/kernel/rcu/tiny.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/rcu/tiny.c	2015-03-03 08:05:18.000000000 +0100
+@@ -370,6 +370,7 @@
+ }
+ EXPORT_SYMBOL_GPL(call_rcu_sched);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /*
+  * Post an RCU bottom-half callback to be invoked after any subsequent
+  * quiescent state.
+@@ -379,6 +380,7 @@
+ 	__call_rcu(head, func, &rcu_bh_ctrlblk);
+ }
+ EXPORT_SYMBOL_GPL(call_rcu_bh);
++#endif
+ 
+ void rcu_init(void)
+ {
+diff -Nur linux-3.18.8.orig/kernel/rcu/tree.c linux-3.18.8/kernel/rcu/tree.c
+--- linux-3.18.8.orig/kernel/rcu/tree.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/rcu/tree.c	2015-03-03 08:05:18.000000000 +0100
+@@ -56,6 +56,11 @@
+ #include <linux/random.h>
+ #include <linux/ftrace_event.h>
+ #include <linux/suspend.h>
++#include <linux/delay.h>
++#include <linux/gfp.h>
++#include <linux/oom.h>
++#include <linux/smpboot.h>
++#include "../time/tick-internal.h"
+ 
+ #include "tree.h"
+ #include "rcu.h"
+@@ -152,8 +157,6 @@
+  */
+ static int rcu_scheduler_fully_active __read_mostly;
+ 
+-#ifdef CONFIG_RCU_BOOST
+-
+ /*
+  * Control variables for per-CPU and per-rcu_node kthreads.  These
+  * handle all flavors of RCU.
+@@ -163,8 +166,6 @@
+ DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
+ DEFINE_PER_CPU(char, rcu_cpu_has_work);
+ 
+-#endif /* #ifdef CONFIG_RCU_BOOST */
+-
+ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
+ static void invoke_rcu_core(void);
+ static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp);
+@@ -207,6 +208,19 @@
+ 	}
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++static void rcu_preempt_qs(void);
++
++void rcu_bh_qs(void)
++{
++	unsigned long flags;
++
++	/* Callers to this function, rcu_preempt_qs(), must disable irqs. */
++	local_irq_save(flags);
++	rcu_preempt_qs();
++	local_irq_restore(flags);
++}
++#else
+ void rcu_bh_qs(void)
+ {
+ 	if (!__this_cpu_read(rcu_bh_data.passed_quiesce)) {
+@@ -216,6 +230,7 @@
+ 		__this_cpu_write(rcu_bh_data.passed_quiesce, 1);
+ 	}
+ }
++#endif
+ 
+ static DEFINE_PER_CPU(int, rcu_sched_qs_mask);
+ 
+@@ -336,6 +351,7 @@
+ }
+ EXPORT_SYMBOL_GPL(rcu_batches_completed_sched);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /*
+  * Return the number of RCU BH batches processed thus far for debug & stats.
+  */
+@@ -362,6 +378,7 @@
+ 	force_quiescent_state(&rcu_bh_state);
+ }
+ EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
++#endif
+ 
+ /*
+  * Show the state of the grace-period kthreads.
+@@ -1411,7 +1428,7 @@
+ 	    !ACCESS_ONCE(rsp->gp_flags) ||
+ 	    !rsp->gp_kthread)
+ 		return;
+-	wake_up(&rsp->gp_wq);
++	swait_wake(&rsp->gp_wq);
+ }
+ 
+ /*
+@@ -1793,7 +1810,7 @@
+ 					       ACCESS_ONCE(rsp->gpnum),
+ 					       TPS("reqwait"));
+ 			rsp->gp_state = RCU_GP_WAIT_GPS;
+-			wait_event_interruptible(rsp->gp_wq,
++			swait_event_interruptible(rsp->gp_wq,
+ 						 ACCESS_ONCE(rsp->gp_flags) &
+ 						 RCU_GP_FLAG_INIT);
+ 			/* Locking provides needed memory barrier. */
+@@ -1821,7 +1838,7 @@
+ 					       ACCESS_ONCE(rsp->gpnum),
+ 					       TPS("fqswait"));
+ 			rsp->gp_state = RCU_GP_WAIT_FQS;
+-			ret = wait_event_interruptible_timeout(rsp->gp_wq,
++			ret = swait_event_interruptible_timeout(rsp->gp_wq,
+ 					((gf = ACCESS_ONCE(rsp->gp_flags)) &
+ 					 RCU_GP_FLAG_FQS) ||
+ 					(!ACCESS_ONCE(rnp->qsmask) &&
+@@ -2565,16 +2582,14 @@
+ /*
+  * Do RCU core processing for the current CPU.
+  */
+-static void rcu_process_callbacks(struct softirq_action *unused)
++static void rcu_process_callbacks(void)
+ {
+ 	struct rcu_state *rsp;
+ 
+ 	if (cpu_is_offline(smp_processor_id()))
+ 		return;
+-	trace_rcu_utilization(TPS("Start RCU core"));
+ 	for_each_rcu_flavor(rsp)
+ 		__rcu_process_callbacks(rsp);
+-	trace_rcu_utilization(TPS("End RCU core"));
+ }
+ 
+ /*
+@@ -2588,18 +2603,105 @@
+ {
+ 	if (unlikely(!ACCESS_ONCE(rcu_scheduler_fully_active)))
+ 		return;
+-	if (likely(!rsp->boost)) {
+-		rcu_do_batch(rsp, rdp);
++	rcu_do_batch(rsp, rdp);
++}
++
++static void rcu_wake_cond(struct task_struct *t, int status)
++{
++	/*
++	 * If the thread is yielding, only wake it when this
++	 * is invoked from idle
++	 */
++	if (t && (status != RCU_KTHREAD_YIELDING || is_idle_task(current)))
++		wake_up_process(t);
++}
++
++/*
++ * Wake up this CPU's rcuc kthread to do RCU core processing.
++ */
++static void invoke_rcu_core(void)
++{
++	unsigned long flags;
++	struct task_struct *t;
++
++	if (!cpu_online(smp_processor_id()))
+ 		return;
++	local_irq_save(flags);
++	__this_cpu_write(rcu_cpu_has_work, 1);
++	t = __this_cpu_read(rcu_cpu_kthread_task);
++	if (t != NULL && current != t)
++		rcu_wake_cond(t, __this_cpu_read(rcu_cpu_kthread_status));
++	local_irq_restore(flags);
++}
++
++static void rcu_cpu_kthread_park(unsigned int cpu)
++{
++	per_cpu(rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
++}
++
++static int rcu_cpu_kthread_should_run(unsigned int cpu)
++{
++	return __this_cpu_read(rcu_cpu_has_work);
++}
++
++/*
++ * Per-CPU kernel thread that invokes RCU callbacks.  This replaces the
++ * RCU softirq used in flavors and configurations of RCU that do not
++ * support RCU priority boosting.
++ */
++static void rcu_cpu_kthread(unsigned int cpu)
++{
++	unsigned int *statusp = &__get_cpu_var(rcu_cpu_kthread_status);
++	char work, *workp = &__get_cpu_var(rcu_cpu_has_work);
++	int spincnt;
++
++	for (spincnt = 0; spincnt < 10; spincnt++) {
++		trace_rcu_utilization(TPS("Start CPU kthread@rcu_wait"));
++		local_bh_disable();
++		*statusp = RCU_KTHREAD_RUNNING;
++		this_cpu_inc(rcu_cpu_kthread_loops);
++		local_irq_disable();
++		work = *workp;
++		*workp = 0;
++		local_irq_enable();
++		if (work)
++			rcu_process_callbacks();
++		local_bh_enable();
++		if (*workp == 0) {
++			trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
++			*statusp = RCU_KTHREAD_WAITING;
++			return;
++		}
+ 	}
+-	invoke_rcu_callbacks_kthread();
++	*statusp = RCU_KTHREAD_YIELDING;
++	trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
++	schedule_timeout_interruptible(2);
++	trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
++	*statusp = RCU_KTHREAD_WAITING;
+ }
+ 
+-static void invoke_rcu_core(void)
++static struct smp_hotplug_thread rcu_cpu_thread_spec = {
++	.store			= &rcu_cpu_kthread_task,
++	.thread_should_run	= rcu_cpu_kthread_should_run,
++	.thread_fn		= rcu_cpu_kthread,
++	.thread_comm		= "rcuc/%u",
++	.setup			= rcu_cpu_kthread_setup,
++	.park			= rcu_cpu_kthread_park,
++};
++
++/*
++ * Spawn per-CPU RCU core processing kthreads.
++ */
++static int __init rcu_spawn_core_kthreads(void)
+ {
+-	if (cpu_online(smp_processor_id()))
+-		raise_softirq(RCU_SOFTIRQ);
++	int cpu;
++
++	for_each_possible_cpu(cpu)
++		per_cpu(rcu_cpu_has_work, cpu) = 0;
++	BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
++	return 0;
+ }
++early_initcall(rcu_spawn_core_kthreads);
+ 
+ /*
+  * Handle any core-RCU processing required by a call_rcu() invocation.
+@@ -2734,6 +2836,7 @@
+ }
+ EXPORT_SYMBOL_GPL(call_rcu_sched);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /*
+  * Queue an RCU callback for invocation after a quicker grace period.
+  */
+@@ -2742,6 +2845,7 @@
+ 	__call_rcu(head, func, &rcu_bh_state, -1, 0);
+ }
+ EXPORT_SYMBOL_GPL(call_rcu_bh);
++#endif
+ 
+ /*
+  * Queue an RCU callback for lazy invocation after a grace period.
+@@ -2833,6 +2937,7 @@
+ }
+ EXPORT_SYMBOL_GPL(synchronize_sched);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /**
+  * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed.
+  *
+@@ -2859,6 +2964,7 @@
+ 		wait_rcu_gp(call_rcu_bh);
+ }
+ EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
++#endif
+ 
+ /**
+  * get_state_synchronize_rcu - Snapshot current RCU state
+@@ -3341,6 +3447,7 @@
+ 	mutex_unlock(&rsp->barrier_mutex);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /**
+  * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
+  */
+@@ -3349,6 +3456,7 @@
+ 	_rcu_barrier(&rcu_bh_state);
+ }
+ EXPORT_SYMBOL_GPL(rcu_barrier_bh);
++#endif
+ 
+ /**
+  * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
+@@ -3658,7 +3766,7 @@
+ 	}
+ 
+ 	rsp->rda = rda;
+-	init_waitqueue_head(&rsp->gp_wq);
++	init_swait_head(&rsp->gp_wq);
+ 	rnp = rsp->level[rcu_num_lvls - 1];
+ 	for_each_possible_cpu(i) {
+ 		while (i > rnp->grphi)
+@@ -3755,7 +3863,6 @@
+ 	rcu_init_one(&rcu_bh_state, &rcu_bh_data);
+ 	rcu_init_one(&rcu_sched_state, &rcu_sched_data);
+ 	__rcu_init_preempt();
+-	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+ 
+ 	/*
+ 	 * We don't need protection against CPU-hotplug here because
+diff -Nur linux-3.18.8.orig/kernel/rcu/tree.h linux-3.18.8/kernel/rcu/tree.h
+--- linux-3.18.8.orig/kernel/rcu/tree.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/rcu/tree.h	2015-03-03 08:05:18.000000000 +0100
+@@ -28,6 +28,7 @@
+ #include <linux/cpumask.h>
+ #include <linux/seqlock.h>
+ #include <linux/irq_work.h>
++#include <linux/wait-simple.h>
+ 
+ /*
+  * Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and
+@@ -208,7 +209,7 @@
+ 				/*  This can happen due to race conditions. */
+ #endif /* #ifdef CONFIG_RCU_BOOST */
+ #ifdef CONFIG_RCU_NOCB_CPU
+-	wait_queue_head_t nocb_gp_wq[2];
++	struct swait_head nocb_gp_wq[2];
+ 				/* Place for rcu_nocb_kthread() to wait GP. */
+ #endif /* #ifdef CONFIG_RCU_NOCB_CPU */
+ 	int need_future_gp[2];
+@@ -348,7 +349,7 @@
+ 	atomic_long_t nocb_follower_count_lazy; /*  (approximate). */
+ 	int nocb_p_count;		/* # CBs being invoked by kthread */
+ 	int nocb_p_count_lazy;		/*  (approximate). */
+-	wait_queue_head_t nocb_wq;	/* For nocb kthreads to sleep on. */
++	struct swait_head nocb_wq;	/* For nocb kthreads to sleep on. */
+ 	struct task_struct *nocb_kthread;
+ 	int nocb_defer_wakeup;		/* Defer wakeup of nocb_kthread. */
+ 
+@@ -439,7 +440,7 @@
+ 	unsigned long gpnum;			/* Current gp number. */
+ 	unsigned long completed;		/* # of last completed gp. */
+ 	struct task_struct *gp_kthread;		/* Task for grace periods. */
+-	wait_queue_head_t gp_wq;		/* Where GP task waits. */
++	struct swait_head gp_wq;		/* Where GP task waits. */
+ 	short gp_flags;				/* Commands for GP task. */
+ 	short gp_state;				/* GP kthread sleep state. */
+ 
+@@ -570,10 +571,9 @@
+ static void __init __rcu_init_preempt(void);
+ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
+ static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
+-static void invoke_rcu_callbacks_kthread(void);
+ static bool rcu_is_callbacks_kthread(void);
++static void rcu_cpu_kthread_setup(unsigned int cpu);
+ #ifdef CONFIG_RCU_BOOST
+-static void rcu_preempt_do_callbacks(void);
+ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
+ 						 struct rcu_node *rnp);
+ #endif /* #ifdef CONFIG_RCU_BOOST */
+diff -Nur linux-3.18.8.orig/kernel/rcu/tree_plugin.h linux-3.18.8/kernel/rcu/tree_plugin.h
+--- linux-3.18.8.orig/kernel/rcu/tree_plugin.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/rcu/tree_plugin.h	2015-03-03 08:05:18.000000000 +0100
+@@ -24,12 +24,6 @@
+  *	   Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+  */
+ 
+-#include <linux/delay.h>
+-#include <linux/gfp.h>
+-#include <linux/oom.h>
+-#include <linux/smpboot.h>
+-#include "../time/tick-internal.h"
+-
+ #define RCU_KTHREAD_PRIO 1
+ 
+ #ifdef CONFIG_RCU_BOOST
+@@ -335,7 +329,7 @@
+ 	}
+ 
+ 	/* Hardware IRQ handlers cannot block, complain if they get here. */
+-	if (WARN_ON_ONCE(in_irq() || in_serving_softirq())) {
++	if (WARN_ON_ONCE(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET))) {
+ 		local_irq_restore(flags);
+ 		return;
+ 	}
+@@ -635,15 +629,6 @@
+ 		t->rcu_read_unlock_special.b.need_qs = true;
+ }
+ 
+-#ifdef CONFIG_RCU_BOOST
+-
+-static void rcu_preempt_do_callbacks(void)
+-{
+-	rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data));
+-}
+-
+-#endif /* #ifdef CONFIG_RCU_BOOST */
+-
+ /*
+  * Queue a preemptible-RCU callback for invocation after a grace period.
+  */
+@@ -1072,6 +1057,19 @@
+ 
+ #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
+ 
++/*
++ * If boosting, set rcuc kthreads to realtime priority.
++ */
++static void rcu_cpu_kthread_setup(unsigned int cpu)
++{
++#ifdef CONFIG_RCU_BOOST
++	struct sched_param sp;
++
++	sp.sched_priority = RCU_KTHREAD_PRIO;
++	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
++#endif /* #ifdef CONFIG_RCU_BOOST */
++}
++
+ #ifdef CONFIG_RCU_BOOST
+ 
+ #include "../locking/rtmutex_common.h"
+@@ -1103,16 +1101,6 @@
+ 
+ #endif /* #else #ifdef CONFIG_RCU_TRACE */
+ 
+-static void rcu_wake_cond(struct task_struct *t, int status)
+-{
+-	/*
+-	 * If the thread is yielding, only wake it when this
+-	 * is invoked from idle
+-	 */
+-	if (status != RCU_KTHREAD_YIELDING || is_idle_task(current))
+-		wake_up_process(t);
+-}
+-
+ /*
+  * Carry out RCU priority boosting on the task indicated by ->exp_tasks
+  * or ->boost_tasks, advancing the pointer to the next task in the
+@@ -1261,23 +1249,6 @@
+ }
+ 
+ /*
+- * Wake up the per-CPU kthread to invoke RCU callbacks.
+- */
+-static void invoke_rcu_callbacks_kthread(void)
+-{
+-	unsigned long flags;
+-
+-	local_irq_save(flags);
+-	__this_cpu_write(rcu_cpu_has_work, 1);
+-	if (__this_cpu_read(rcu_cpu_kthread_task) != NULL &&
+-	    current != __this_cpu_read(rcu_cpu_kthread_task)) {
+-		rcu_wake_cond(__this_cpu_read(rcu_cpu_kthread_task),
+-			      __this_cpu_read(rcu_cpu_kthread_status));
+-	}
+-	local_irq_restore(flags);
+-}
+-
+-/*
+  * Is the current CPU running the RCU-callbacks kthread?
+  * Caller must have preemption disabled.
+  */
+@@ -1332,67 +1303,6 @@
+ 	return 0;
+ }
+ 
+-static void rcu_kthread_do_work(void)
+-{
+-	rcu_do_batch(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data));
+-	rcu_do_batch(&rcu_bh_state, this_cpu_ptr(&rcu_bh_data));
+-	rcu_preempt_do_callbacks();
+-}
+-
+-static void rcu_cpu_kthread_setup(unsigned int cpu)
+-{
+-	struct sched_param sp;
+-
+-	sp.sched_priority = RCU_KTHREAD_PRIO;
+-	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
+-}
+-
+-static void rcu_cpu_kthread_park(unsigned int cpu)
+-{
+-	per_cpu(rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
+-}
+-
+-static int rcu_cpu_kthread_should_run(unsigned int cpu)
+-{
+-	return __this_cpu_read(rcu_cpu_has_work);
+-}
+-
+-/*
+- * Per-CPU kernel thread that invokes RCU callbacks.  This replaces the
+- * RCU softirq used in flavors and configurations of RCU that do not
+- * support RCU priority boosting.
+- */
+-static void rcu_cpu_kthread(unsigned int cpu)
+-{
+-	unsigned int *statusp = this_cpu_ptr(&rcu_cpu_kthread_status);
+-	char work, *workp = this_cpu_ptr(&rcu_cpu_has_work);
+-	int spincnt;
+-
+-	for (spincnt = 0; spincnt < 10; spincnt++) {
+-		trace_rcu_utilization(TPS("Start CPU kthread@rcu_wait"));
+-		local_bh_disable();
+-		*statusp = RCU_KTHREAD_RUNNING;
+-		this_cpu_inc(rcu_cpu_kthread_loops);
+-		local_irq_disable();
+-		work = *workp;
+-		*workp = 0;
+-		local_irq_enable();
+-		if (work)
+-			rcu_kthread_do_work();
+-		local_bh_enable();
+-		if (*workp == 0) {
+-			trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
+-			*statusp = RCU_KTHREAD_WAITING;
+-			return;
+-		}
+-	}
+-	*statusp = RCU_KTHREAD_YIELDING;
+-	trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
+-	schedule_timeout_interruptible(2);
+-	trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
+-	*statusp = RCU_KTHREAD_WAITING;
+-}
+-
+ /*
+  * Set the per-rcu_node kthread's affinity to cover all CPUs that are
+  * served by the rcu_node in question.  The CPU hotplug lock is still
+@@ -1426,26 +1336,13 @@
+ 	free_cpumask_var(cm);
+ }
+ 
+-static struct smp_hotplug_thread rcu_cpu_thread_spec = {
+-	.store			= &rcu_cpu_kthread_task,
+-	.thread_should_run	= rcu_cpu_kthread_should_run,
+-	.thread_fn		= rcu_cpu_kthread,
+-	.thread_comm		= "rcuc/%u",
+-	.setup			= rcu_cpu_kthread_setup,
+-	.park			= rcu_cpu_kthread_park,
+-};
+-
+ /*
+  * Spawn boost kthreads -- called as soon as the scheduler is running.
+  */
+ static void __init rcu_spawn_boost_kthreads(void)
+ {
+ 	struct rcu_node *rnp;
+-	int cpu;
+ 
+-	for_each_possible_cpu(cpu)
+-		per_cpu(rcu_cpu_has_work, cpu) = 0;
+-	BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
+ 	rnp = rcu_get_root(rcu_state_p);
+ 	(void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
+ 	if (NUM_RCU_NODES > 1) {
+@@ -1472,11 +1369,6 @@
+ 	raw_spin_unlock_irqrestore(&rnp->lock, flags);
+ }
+ 
+-static void invoke_rcu_callbacks_kthread(void)
+-{
+-	WARN_ON_ONCE(1);
+-}
+-
+ static bool rcu_is_callbacks_kthread(void)
+ {
+ 	return false;
+@@ -1500,7 +1392,7 @@
+ 
+ #endif /* #else #ifdef CONFIG_RCU_BOOST */
+ 
+-#if !defined(CONFIG_RCU_FAST_NO_HZ)
++#if !defined(CONFIG_RCU_FAST_NO_HZ) || defined(CONFIG_PREEMPT_RT_FULL)
+ 
+ /*
+  * Check to see if any future RCU-related work will need to be done
+@@ -1518,7 +1410,9 @@
+ 	return rcu_cpu_has_callbacks(cpu, NULL);
+ }
+ #endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
++#endif /* !defined(CONFIG_RCU_FAST_NO_HZ) || defined(CONFIG_PREEMPT_RT_FULL) */
+ 
++#if !defined(CONFIG_RCU_FAST_NO_HZ)
+ /*
+  * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
+  * after it.
+@@ -1615,6 +1509,8 @@
+ 	return cbs_ready;
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++
+ /*
+  * Allow the CPU to enter dyntick-idle mode unless it has callbacks ready
+  * to invoke.  If the CPU has callbacks, try to advance them.  Tell the
+@@ -1655,7 +1551,7 @@
+ 	return 0;
+ }
+ #endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
+-
++#endif /* #ifndef CONFIG_PREEMPT_RT_FULL */
+ /*
+  * Prepare a CPU for idle from an RCU perspective.  The first major task
+  * is to sense whether nohz mode has been enabled or disabled via sysfs.
+@@ -2001,7 +1897,7 @@
+  */
+ static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
+ {
+-	wake_up_all(&rnp->nocb_gp_wq[rnp->completed & 0x1]);
++	swait_wake_all(&rnp->nocb_gp_wq[rnp->completed & 0x1]);
+ }
+ 
+ /*
+@@ -2019,8 +1915,8 @@
+ 
+ static void rcu_init_one_nocb(struct rcu_node *rnp)
+ {
+-	init_waitqueue_head(&rnp->nocb_gp_wq[0]);
+-	init_waitqueue_head(&rnp->nocb_gp_wq[1]);
++	init_swait_head(&rnp->nocb_gp_wq[0]);
++	init_swait_head(&rnp->nocb_gp_wq[1]);
+ }
+ 
+ #ifndef CONFIG_RCU_NOCB_CPU_ALL
+@@ -2045,7 +1941,7 @@
+ 	if (ACCESS_ONCE(rdp_leader->nocb_leader_sleep) || force) {
+ 		/* Prior smp_mb__after_atomic() orders against prior enqueue. */
+ 		ACCESS_ONCE(rdp_leader->nocb_leader_sleep) = false;
+-		wake_up(&rdp_leader->nocb_wq);
++		swait_wake(&rdp_leader->nocb_wq);
+ 	}
+ }
+ 
+@@ -2238,7 +2134,7 @@
+ 	 */
+ 	trace_rcu_future_gp(rnp, rdp, c, TPS("StartWait"));
+ 	for (;;) {
+-		wait_event_interruptible(
++		swait_event_interruptible(
+ 			rnp->nocb_gp_wq[c & 0x1],
+ 			(d = ULONG_CMP_GE(ACCESS_ONCE(rnp->completed), c)));
+ 		if (likely(d))
+@@ -2266,7 +2162,7 @@
+ 	/* Wait for callbacks to appear. */
+ 	if (!rcu_nocb_poll) {
+ 		trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep");
+-		wait_event_interruptible(my_rdp->nocb_wq,
++		swait_event_interruptible(my_rdp->nocb_wq,
+ 				!ACCESS_ONCE(my_rdp->nocb_leader_sleep));
+ 		/* Memory barrier handled by smp_mb() calls below and repoll. */
+ 	} else if (firsttime) {
+@@ -2347,7 +2243,7 @@
+ 			 * List was empty, wake up the follower.
+ 			 * Memory barriers supplied by atomic_long_add().
+ 			 */
+-			wake_up(&rdp->nocb_wq);
++			swait_wake(&rdp->nocb_wq);
+ 		}
+ 	}
+ 
+@@ -2368,7 +2264,7 @@
+ 		if (!rcu_nocb_poll) {
+ 			trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ 					    "FollowerSleep");
+-			wait_event_interruptible(rdp->nocb_wq,
++			swait_event_interruptible(rdp->nocb_wq,
+ 						 ACCESS_ONCE(rdp->nocb_follower_head));
+ 		} else if (firsttime) {
+ 			/* Don't drown trace log with "Poll"! */
+@@ -2539,7 +2435,7 @@
+ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
+ {
+ 	rdp->nocb_tail = &rdp->nocb_head;
+-	init_waitqueue_head(&rdp->nocb_wq);
++	init_swait_head(&rdp->nocb_wq);
+ 	rdp->nocb_follower_tail = &rdp->nocb_follower_head;
+ }
+ 
+diff -Nur linux-3.18.8.orig/kernel/rcu/update.c linux-3.18.8/kernel/rcu/update.c
+--- linux-3.18.8.orig/kernel/rcu/update.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/rcu/update.c	2015-03-03 08:05:18.000000000 +0100
+@@ -170,6 +170,7 @@
+ }
+ EXPORT_SYMBOL_GPL(rcu_read_lock_held);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /**
+  * rcu_read_lock_bh_held() - might we be in RCU-bh read-side critical section?
+  *
+@@ -196,6 +197,7 @@
+ 	return in_softirq() || irqs_disabled();
+ }
+ EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
++#endif
+ 
+ #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+ 
+diff -Nur linux-3.18.8.orig/kernel/relay.c linux-3.18.8/kernel/relay.c
+--- linux-3.18.8.orig/kernel/relay.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/relay.c	2015-03-03 08:05:18.000000000 +0100
+@@ -339,6 +339,10 @@
+ {
+ 	struct rchan_buf *buf = (struct rchan_buf *)data;
+ 	wake_up_interruptible(&buf->read_wait);
++	/*
++	 * Stupid polling for now:
++	 */
++	mod_timer(&buf->timer, jiffies + 1);
+ }
+ 
+ /**
+@@ -356,6 +360,7 @@
+ 		init_waitqueue_head(&buf->read_wait);
+ 		kref_init(&buf->kref);
+ 		setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf);
++		mod_timer(&buf->timer, jiffies + 1);
+ 	} else
+ 		del_timer_sync(&buf->timer);
+ 
+@@ -739,15 +744,6 @@
+ 		else
+ 			buf->early_bytes += buf->chan->subbuf_size -
+ 					    buf->padding[old_subbuf];
+-		smp_mb();
+-		if (waitqueue_active(&buf->read_wait))
+-			/*
+-			 * Calling wake_up_interruptible() from here
+-			 * will deadlock if we happen to be logging
+-			 * from the scheduler (trying to re-grab
+-			 * rq->lock), so defer it.
+-			 */
+-			mod_timer(&buf->timer, jiffies + 1);
+ 	}
+ 
+ 	old = buf->data;
+diff -Nur linux-3.18.8.orig/kernel/res_counter.c linux-3.18.8/kernel/res_counter.c
+--- linux-3.18.8.orig/kernel/res_counter.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/res_counter.c	2015-03-03 08:05:18.000000000 +0100
+@@ -59,7 +59,7 @@
+ 
+ 	r = ret = 0;
+ 	*limit_fail_at = NULL;
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	for (c = counter; c != NULL; c = c->parent) {
+ 		spin_lock(&c->lock);
+ 		r = res_counter_charge_locked(c, val, force);
+@@ -79,7 +79,7 @@
+ 			spin_unlock(&u->lock);
+ 		}
+ 	}
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 
+ 	return ret;
+ }
+@@ -104,7 +104,7 @@
+ 	struct res_counter *c;
+ 	u64 ret = 0;
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	for (c = counter; c != top; c = c->parent) {
+ 		u64 r;
+ 		spin_lock(&c->lock);
+@@ -113,7 +113,7 @@
+ 			ret = r;
+ 		spin_unlock(&c->lock);
+ 	}
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 	return ret;
+ }
+ 
+diff -Nur linux-3.18.8.orig/kernel/sched/completion.c linux-3.18.8/kernel/sched/completion.c
+--- linux-3.18.8.orig/kernel/sched/completion.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/completion.c	2015-03-03 08:05:18.000000000 +0100
+@@ -30,10 +30,10 @@
+ {
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&x->wait.lock, flags);
++	raw_spin_lock_irqsave(&x->wait.lock, flags);
+ 	x->done++;
+-	__wake_up_locked(&x->wait, TASK_NORMAL, 1);
+-	spin_unlock_irqrestore(&x->wait.lock, flags);
++	__swait_wake_locked(&x->wait, TASK_NORMAL, 1);
++	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+ }
+ EXPORT_SYMBOL(complete);
+ 
+@@ -50,10 +50,10 @@
+ {
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&x->wait.lock, flags);
++	raw_spin_lock_irqsave(&x->wait.lock, flags);
+ 	x->done += UINT_MAX/2;
+-	__wake_up_locked(&x->wait, TASK_NORMAL, 0);
+-	spin_unlock_irqrestore(&x->wait.lock, flags);
++	__swait_wake_locked(&x->wait, TASK_NORMAL, 0);
++	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+ }
+ EXPORT_SYMBOL(complete_all);
+ 
+@@ -62,20 +62,20 @@
+ 		   long (*action)(long), long timeout, int state)
+ {
+ 	if (!x->done) {
+-		DECLARE_WAITQUEUE(wait, current);
++		DEFINE_SWAITER(wait);
+ 
+-		__add_wait_queue_tail_exclusive(&x->wait, &wait);
++		swait_prepare_locked(&x->wait, &wait);
+ 		do {
+ 			if (signal_pending_state(state, current)) {
+ 				timeout = -ERESTARTSYS;
+ 				break;
+ 			}
+ 			__set_current_state(state);
+-			spin_unlock_irq(&x->wait.lock);
++			raw_spin_unlock_irq(&x->wait.lock);
+ 			timeout = action(timeout);
+-			spin_lock_irq(&x->wait.lock);
++			raw_spin_lock_irq(&x->wait.lock);
+ 		} while (!x->done && timeout);
+-		__remove_wait_queue(&x->wait, &wait);
++		swait_finish_locked(&x->wait, &wait);
+ 		if (!x->done)
+ 			return timeout;
+ 	}
+@@ -89,9 +89,9 @@
+ {
+ 	might_sleep();
+ 
+-	spin_lock_irq(&x->wait.lock);
++	raw_spin_lock_irq(&x->wait.lock);
+ 	timeout = do_wait_for_common(x, action, timeout, state);
+-	spin_unlock_irq(&x->wait.lock);
++	raw_spin_unlock_irq(&x->wait.lock);
+ 	return timeout;
+ }
+ 
+@@ -267,12 +267,12 @@
+ 	unsigned long flags;
+ 	int ret = 1;
+ 
+-	spin_lock_irqsave(&x->wait.lock, flags);
++	raw_spin_lock_irqsave(&x->wait.lock, flags);
+ 	if (!x->done)
+ 		ret = 0;
+ 	else
+ 		x->done--;
+-	spin_unlock_irqrestore(&x->wait.lock, flags);
++	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+ 	return ret;
+ }
+ EXPORT_SYMBOL(try_wait_for_completion);
+@@ -290,10 +290,10 @@
+ 	unsigned long flags;
+ 	int ret = 1;
+ 
+-	spin_lock_irqsave(&x->wait.lock, flags);
++	raw_spin_lock_irqsave(&x->wait.lock, flags);
+ 	if (!x->done)
+ 		ret = 0;
+-	spin_unlock_irqrestore(&x->wait.lock, flags);
++	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
+ 	return ret;
+ }
+ EXPORT_SYMBOL(completion_done);
+diff -Nur linux-3.18.8.orig/kernel/sched/core.c linux-3.18.8/kernel/sched/core.c
+--- linux-3.18.8.orig/kernel/sched/core.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/core.c	2015-03-03 08:05:18.000000000 +0100
+@@ -280,7 +280,11 @@
+  * Number of tasks to iterate in a single balance run.
+  * Limited because this is done with IRQs disabled.
+  */
++#ifndef CONFIG_PREEMPT_RT_FULL
+ const_debug unsigned int sysctl_sched_nr_migrate = 32;
++#else
++const_debug unsigned int sysctl_sched_nr_migrate = 8;
++#endif
+ 
+ /*
+  * period over which we average the RT time consumption, measured
+@@ -511,6 +515,7 @@
+ 
+ 	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ 	rq->hrtick_timer.function = hrtick;
++	rq->hrtick_timer.irqsafe = 1;
+ }
+ #else	/* CONFIG_SCHED_HRTICK */
+ static inline void hrtick_clear(struct rq *rq)
+@@ -622,6 +627,38 @@
+ 		trace_sched_wake_idle_without_ipi(cpu);
+ }
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++void resched_curr_lazy(struct rq *rq)
++{
++	struct task_struct *curr = rq->curr;
++	int cpu;
++
++	if (!sched_feat(PREEMPT_LAZY)) {
++		resched_curr(rq);
++		return;
++	}
++
++	lockdep_assert_held(&rq->lock);
++
++	if (test_tsk_need_resched(curr))
++		return;
++
++	if (test_tsk_need_resched_lazy(curr))
++		return;
++
++	set_tsk_need_resched_lazy(curr);
++
++	cpu = cpu_of(rq);
++	if (cpu == smp_processor_id())
++		return;
++
++	/* NEED_RESCHED_LAZY must be visible before we test polling */
++	smp_mb();
++	if (!tsk_is_polling(curr))
++		smp_send_reschedule(cpu);
++}
++#endif
++
+ void resched_cpu(int cpu)
+ {
+ 	struct rq *rq = cpu_rq(cpu);
+@@ -645,12 +682,14 @@
+  */
+ int get_nohz_timer_target(int pinned)
+ {
+-	int cpu = smp_processor_id();
++	int cpu;
+ 	int i;
+ 	struct sched_domain *sd;
+ 
++	preempt_disable_rt();
++	cpu = smp_processor_id();
+ 	if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu))
+-		return cpu;
++		goto preempt_en_rt;
+ 
+ 	rcu_read_lock();
+ 	for_each_domain(cpu, sd) {
+@@ -663,6 +702,8 @@
+ 	}
+ unlock:
+ 	rcu_read_unlock();
++preempt_en_rt:
++	preempt_enable_rt();
+ 	return cpu;
+ }
+ /*
+@@ -1193,6 +1234,18 @@
+ 
+ static int migration_cpu_stop(void *data);
+ 
++static bool check_task_state(struct task_struct *p, long match_state)
++{
++	bool match = false;
++
++	raw_spin_lock_irq(&p->pi_lock);
++	if (p->state == match_state || p->saved_state == match_state)
++		match = true;
++	raw_spin_unlock_irq(&p->pi_lock);
++
++	return match;
++}
++
+ /*
+  * wait_task_inactive - wait for a thread to unschedule.
+  *
+@@ -1237,7 +1290,7 @@
+ 		 * is actually now running somewhere else!
+ 		 */
+ 		while (task_running(rq, p)) {
+-			if (match_state && unlikely(p->state != match_state))
++			if (match_state && !check_task_state(p, match_state))
+ 				return 0;
+ 			cpu_relax();
+ 		}
+@@ -1252,7 +1305,8 @@
+ 		running = task_running(rq, p);
+ 		queued = task_on_rq_queued(p);
+ 		ncsw = 0;
+-		if (!match_state || p->state == match_state)
++		if (!match_state || p->state == match_state ||
++		    p->saved_state == match_state)
+ 			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+ 		task_rq_unlock(rq, p, &flags);
+ 
+@@ -1477,10 +1531,6 @@
+ {
+ 	activate_task(rq, p, en_flags);
+ 	p->on_rq = TASK_ON_RQ_QUEUED;
+-
+-	/* if a worker is waking up, notify workqueue */
+-	if (p->flags & PF_WQ_WORKER)
+-		wq_worker_waking_up(p, cpu_of(rq));
+ }
+ 
+ /*
+@@ -1694,8 +1744,27 @@
+ 	 */
+ 	smp_mb__before_spinlock();
+ 	raw_spin_lock_irqsave(&p->pi_lock, flags);
+-	if (!(p->state & state))
++	if (!(p->state & state)) {
++		/*
++		 * The task might be running due to a spinlock sleeper
++		 * wakeup. Check the saved state and set it to running
++		 * if the wakeup condition is true.
++		 */
++		if (!(wake_flags & WF_LOCK_SLEEPER)) {
++			if (p->saved_state & state) {
++				p->saved_state = TASK_RUNNING;
++				success = 1;
++			}
++		}
+ 		goto out;
++	}
++
++	/*
++	 * If this is a regular wakeup, then we can unconditionally
++	 * clear the saved state of a "lock sleeper".
++	 */
++	if (!(wake_flags & WF_LOCK_SLEEPER))
++		p->saved_state = TASK_RUNNING;
+ 
+ 	success = 1; /* we're going to change ->state */
+ 	cpu = task_cpu(p);
+@@ -1738,42 +1807,6 @@
+ }
+ 
+ /**
+- * try_to_wake_up_local - try to wake up a local task with rq lock held
+- * @p: the thread to be awakened
+- *
+- * Put @p on the run-queue if it's not already there. The caller must
+- * ensure that this_rq() is locked, @p is bound to this_rq() and not
+- * the current task.
+- */
+-static void try_to_wake_up_local(struct task_struct *p)
+-{
+-	struct rq *rq = task_rq(p);
+-
+-	if (WARN_ON_ONCE(rq != this_rq()) ||
+-	    WARN_ON_ONCE(p == current))
+-		return;
+-
+-	lockdep_assert_held(&rq->lock);
+-
+-	if (!raw_spin_trylock(&p->pi_lock)) {
+-		raw_spin_unlock(&rq->lock);
+-		raw_spin_lock(&p->pi_lock);
+-		raw_spin_lock(&rq->lock);
+-	}
+-
+-	if (!(p->state & TASK_NORMAL))
+-		goto out;
+-
+-	if (!task_on_rq_queued(p))
+-		ttwu_activate(rq, p, ENQUEUE_WAKEUP);
+-
+-	ttwu_do_wakeup(rq, p, 0);
+-	ttwu_stat(p, smp_processor_id(), 0);
+-out:
+-	raw_spin_unlock(&p->pi_lock);
+-}
+-
+-/**
+  * wake_up_process - Wake up a specific process
+  * @p: The process to be woken up.
+  *
+@@ -1787,11 +1820,23 @@
+  */
+ int wake_up_process(struct task_struct *p)
+ {
+-	WARN_ON(task_is_stopped_or_traced(p));
++	WARN_ON(__task_is_stopped_or_traced(p));
+ 	return try_to_wake_up(p, TASK_NORMAL, 0);
+ }
+ EXPORT_SYMBOL(wake_up_process);
+ 
++/**
++ * wake_up_lock_sleeper - Wake up a specific process blocked on a "sleeping lock"
++ * @p: The process to be woken up.
++ *
++ * Same as wake_up_process() above, but wake_flags=WF_LOCK_SLEEPER to indicate
++ * the nature of the wakeup.
++ */
++int wake_up_lock_sleeper(struct task_struct *p)
++{
++	return try_to_wake_up(p, TASK_ALL, WF_LOCK_SLEEPER);
++}
++
+ int wake_up_state(struct task_struct *p, unsigned int state)
+ {
+ 	return try_to_wake_up(p, state, 0);
+@@ -1982,6 +2027,9 @@
+ 	p->on_cpu = 0;
+ #endif
+ 	init_task_preempt_count(p);
++#ifdef CONFIG_HAVE_PREEMPT_LAZY
++	task_thread_info(p)->preempt_lazy_count = 0;
++#endif
+ #ifdef CONFIG_SMP
+ 	plist_node_init(&p->pushable_tasks, MAX_PRIO);
+ 	RB_CLEAR_NODE(&p->pushable_dl_tasks);
+@@ -2265,8 +2313,12 @@
+ 	finish_arch_post_lock_switch();
+ 
+ 	fire_sched_in_preempt_notifiers(current);
++	/*
++	 * We use mmdrop_delayed() here so we don't have to do the
++	 * full __mmdrop() when we are the last user.
++	 */
+ 	if (mm)
+-		mmdrop(mm);
++		mmdrop_delayed(mm);
+ 	if (unlikely(prev_state == TASK_DEAD)) {
+ 		if (prev->sched_class->task_dead)
+ 			prev->sched_class->task_dead(prev);
+@@ -2691,6 +2743,133 @@
+ 	schedstat_inc(this_rq(), sched_count);
+ }
+ 
++#if defined(CONFIG_PREEMPT_RT_FULL) && defined(CONFIG_SMP)
++#define MIGRATE_DISABLE_SET_AFFIN	(1<<30) /* Can't make a negative */
++#define migrate_disabled_updated(p)	((p)->migrate_disable & MIGRATE_DISABLE_SET_AFFIN)
++#define migrate_disable_count(p)	((p)->migrate_disable & ~MIGRATE_DISABLE_SET_AFFIN)
++
++static inline void update_migrate_disable(struct task_struct *p)
++{
++	const struct cpumask *mask;
++
++	if (likely(!p->migrate_disable))
++		return;
++
++	/* Did we already update affinity? */
++	if (unlikely(migrate_disabled_updated(p)))
++		return;
++
++	/*
++	 * Since this is always current we can get away with only locking
++	 * rq->lock, the ->cpus_allowed value can normally only be changed
++	 * while holding both p->pi_lock and rq->lock, but seeing that this
++	 * is current, we cannot actually be waking up, so all code that
++	 * relies on serialization against p->pi_lock is out of scope.
++	 *
++	 * Having rq->lock serializes us against things like
++	 * set_cpus_allowed_ptr() that can still happen concurrently.
++	 */
++	mask = tsk_cpus_allowed(p);
++
++	if (p->sched_class->set_cpus_allowed)
++		p->sched_class->set_cpus_allowed(p, mask);
++	/* mask==cpumask_of(task_cpu(p)) which has a cpumask_weight==1 */
++	p->nr_cpus_allowed = 1;
++
++	/* Let migrate_enable know to fix things back up */
++	p->migrate_disable |= MIGRATE_DISABLE_SET_AFFIN;
++}
++
++void migrate_disable(void)
++{
++	struct task_struct *p = current;
++
++	if (in_atomic()) {
++#ifdef CONFIG_SCHED_DEBUG
++		p->migrate_disable_atomic++;
++#endif
++		return;
++	}
++
++#ifdef CONFIG_SCHED_DEBUG
++	if (unlikely(p->migrate_disable_atomic)) {
++		tracing_off();
++		WARN_ON_ONCE(1);
++	}
++#endif
++
++	if (p->migrate_disable) {
++		p->migrate_disable++;
++		return;
++	}
++
++	preempt_disable();
++	preempt_lazy_disable();
++	pin_current_cpu();
++	p->migrate_disable = 1;
++	preempt_enable();
++}
++EXPORT_SYMBOL(migrate_disable);
++
++void migrate_enable(void)
++{
++	struct task_struct *p = current;
++	const struct cpumask *mask;
++	unsigned long flags;
++	struct rq *rq;
++
++	if (in_atomic()) {
++#ifdef CONFIG_SCHED_DEBUG
++		p->migrate_disable_atomic--;
++#endif
++		return;
++	}
++
++#ifdef CONFIG_SCHED_DEBUG
++	if (unlikely(p->migrate_disable_atomic)) {
++		tracing_off();
++		WARN_ON_ONCE(1);
++	}
++#endif
++	WARN_ON_ONCE(p->migrate_disable <= 0);
++
++	if (migrate_disable_count(p) > 1) {
++		p->migrate_disable--;
++		return;
++	}
++
++	preempt_disable();
++	if (unlikely(migrate_disabled_updated(p))) {
++		/*
++		 * Undo whatever update_migrate_disable() did, also see there
++		 * about locking.
++		 */
++		rq = this_rq();
++		raw_spin_lock_irqsave(&rq->lock, flags);
++
++		/*
++		 * Clearing migrate_disable causes tsk_cpus_allowed to
++		 * show the tasks original cpu affinity.
++		 */
++		p->migrate_disable = 0;
++		mask = tsk_cpus_allowed(p);
++		if (p->sched_class->set_cpus_allowed)
++			p->sched_class->set_cpus_allowed(p, mask);
++		p->nr_cpus_allowed = cpumask_weight(mask);
++		raw_spin_unlock_irqrestore(&rq->lock, flags);
++	} else
++		p->migrate_disable = 0;
++
++	unpin_current_cpu();
++	preempt_enable();
++	preempt_lazy_enable();
++}
++EXPORT_SYMBOL(migrate_enable);
++#else
++static inline void update_migrate_disable(struct task_struct *p) { }
++#define migrate_disabled_updated(p)		0
++#endif
++
+ /*
+  * Pick up the highest-prio task:
+  */
+@@ -2794,6 +2973,8 @@
+ 	smp_mb__before_spinlock();
+ 	raw_spin_lock_irq(&rq->lock);
+ 
++	update_migrate_disable(prev);
++
+ 	switch_count = &prev->nivcsw;
+ 	if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+ 		if (unlikely(signal_pending_state(prev->state, prev))) {
+@@ -2801,19 +2982,6 @@
+ 		} else {
+ 			deactivate_task(rq, prev, DEQUEUE_SLEEP);
+ 			prev->on_rq = 0;
+-
+-			/*
+-			 * If a worker went to sleep, notify and ask workqueue
+-			 * whether it wants to wake up a task to maintain
+-			 * concurrency.
+-			 */
+-			if (prev->flags & PF_WQ_WORKER) {
+-				struct task_struct *to_wakeup;
+-
+-				to_wakeup = wq_worker_sleeping(prev, cpu);
+-				if (to_wakeup)
+-					try_to_wake_up_local(to_wakeup);
+-			}
+ 		}
+ 		switch_count = &prev->nvcsw;
+ 	}
+@@ -2823,6 +2991,7 @@
+ 
+ 	next = pick_next_task(rq, prev);
+ 	clear_tsk_need_resched(prev);
++	clear_tsk_need_resched_lazy(prev);
+ 	clear_preempt_need_resched();
+ 	rq->skip_clock_update = 0;
+ 
+@@ -2852,9 +3021,20 @@
+ 
+ static inline void sched_submit_work(struct task_struct *tsk)
+ {
+-	if (!tsk->state || tsk_is_pi_blocked(tsk))
++	if (!tsk->state)
+ 		return;
+ 	/*
++	 * If a worker went to sleep, notify and ask workqueue whether
++	 * it wants to wake up a task to maintain concurrency.
++	 */
++	if (tsk->flags & PF_WQ_WORKER)
++		wq_worker_sleeping(tsk);
++
++
++	if (tsk_is_pi_blocked(tsk))
++		return;
++
++	/*
+ 	 * If we are going to sleep and we have plugged IO queued,
+ 	 * make sure to submit it to avoid deadlocks.
+ 	 */
+@@ -2862,12 +3042,19 @@
+ 		blk_schedule_flush_plug(tsk);
+ }
+ 
++static inline void sched_update_worker(struct task_struct *tsk)
++{
++	if (tsk->flags & PF_WQ_WORKER)
++		wq_worker_running(tsk);
++}
++
+ asmlinkage __visible void __sched schedule(void)
+ {
+ 	struct task_struct *tsk = current;
+ 
+ 	sched_submit_work(tsk);
+ 	__schedule();
++	sched_update_worker(tsk);
+ }
+ EXPORT_SYMBOL(schedule);
+ 
+@@ -2917,9 +3104,26 @@
+ 	if (likely(!preemptible()))
+ 		return;
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++	/*
++	 * Check for lazy preemption
++	 */
++	if (current_thread_info()->preempt_lazy_count &&
++			!test_thread_flag(TIF_NEED_RESCHED))
++		return;
++#endif
+ 	do {
+ 		__preempt_count_add(PREEMPT_ACTIVE);
++		/*
++		 * The add/subtract must not be traced by the function
++		 * tracer. But we still want to account for the
++		 * preempt off latency tracer. Since the _notrace versions
++		 * of add/subtract skip the accounting for latency tracer
++		 * we must force it manually.
++		 */
++		start_critical_timings();
+ 		__schedule();
++		stop_critical_timings();
+ 		__preempt_count_sub(PREEMPT_ACTIVE);
+ 
+ 		/*
+@@ -4229,9 +4433,16 @@
+ 
+ static void __cond_resched(void)
+ {
+-	__preempt_count_add(PREEMPT_ACTIVE);
+-	__schedule();
+-	__preempt_count_sub(PREEMPT_ACTIVE);
++	do {
++		__preempt_count_add(PREEMPT_ACTIVE);
++		__schedule();
++		__preempt_count_sub(PREEMPT_ACTIVE);
++		/*
++		 * Check again in case we missed a preemption
++		 * opportunity between schedule and now.
++		 */
++		barrier();
++	} while (need_resched());
+ }
+ 
+ int __sched _cond_resched(void)
+@@ -4272,6 +4483,7 @@
+ }
+ EXPORT_SYMBOL(__cond_resched_lock);
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ int __sched __cond_resched_softirq(void)
+ {
+ 	BUG_ON(!in_softirq());
+@@ -4285,6 +4497,7 @@
+ 	return 0;
+ }
+ EXPORT_SYMBOL(__cond_resched_softirq);
++#endif
+ 
+ /**
+  * yield - yield the current processor to other threads.
+@@ -4646,7 +4859,9 @@
+ 
+ 	/* Set the preempt count _outside_ the spinlocks! */
+ 	init_idle_preempt_count(idle, cpu);
+-
++#ifdef CONFIG_HAVE_PREEMPT_LAZY
++	task_thread_info(idle)->preempt_lazy_count = 0;
++#endif
+ 	/*
+ 	 * The idle tasks have their own, simple scheduling class:
+ 	 */
+@@ -4688,11 +4903,91 @@
+ 
+ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+ {
+-	if (p->sched_class && p->sched_class->set_cpus_allowed)
+-		p->sched_class->set_cpus_allowed(p, new_mask);
++	if (!migrate_disabled_updated(p)) {
++		if (p->sched_class && p->sched_class->set_cpus_allowed)
++			p->sched_class->set_cpus_allowed(p, new_mask);
++		p->nr_cpus_allowed = cpumask_weight(new_mask);
++	}
+ 
+ 	cpumask_copy(&p->cpus_allowed, new_mask);
+-	p->nr_cpus_allowed = cpumask_weight(new_mask);
++}
++
++static DEFINE_PER_CPU(struct cpumask, sched_cpumasks);
++static DEFINE_MUTEX(sched_down_mutex);
++static cpumask_t sched_down_cpumask;
++
++void tell_sched_cpu_down_begin(int cpu)
++{
++	mutex_lock(&sched_down_mutex);
++	cpumask_set_cpu(cpu, &sched_down_cpumask);
++	mutex_unlock(&sched_down_mutex);
++}
++
++void tell_sched_cpu_down_done(int cpu)
++{
++	mutex_lock(&sched_down_mutex);
++	cpumask_clear_cpu(cpu, &sched_down_cpumask);
++	mutex_unlock(&sched_down_mutex);
++}
++
++/**
++ * migrate_me - try to move the current task off this cpu
++ *
++ * Used by the pin_current_cpu() code to try to get tasks
++ * to move off the current CPU as it is going down.
++ * It will only move the task if the task isn't pinned to
++ * the CPU (with migrate_disable, affinity or NO_SETAFFINITY)
++ * and the task has to be in a RUNNING state. Otherwise the
++ * movement of the task will wake it up (change its state
++ * to running) when the task did not expect it.
++ *
++ * Returns 1 if it succeeded in moving the current task
++ *         0 otherwise.
++ */
++int migrate_me(void)
++{
++	struct task_struct *p = current;
++	struct migration_arg arg;
++	struct cpumask *cpumask;
++	struct cpumask *mask;
++	unsigned long flags;
++	unsigned int dest_cpu;
++	struct rq *rq;
++
++	/*
++	 * We can not migrate tasks bounded to a CPU or tasks not
++	 * running. The movement of the task will wake it up.
++	 */
++	if (p->flags & PF_NO_SETAFFINITY || p->state)
++		return 0;
++
++	mutex_lock(&sched_down_mutex);
++	rq = task_rq_lock(p, &flags);
++
++	cpumask = &__get_cpu_var(sched_cpumasks);
++	mask = &p->cpus_allowed;
++
++	cpumask_andnot(cpumask, mask, &sched_down_cpumask);
++
++	if (!cpumask_weight(cpumask)) {
++		/* It's only on this CPU? */
++		task_rq_unlock(rq, p, &flags);
++		mutex_unlock(&sched_down_mutex);
++		return 0;
++	}
++
++	dest_cpu = cpumask_any_and(cpu_active_mask, cpumask);
++
++	arg.task = p;
++	arg.dest_cpu = dest_cpu;
++
++	task_rq_unlock(rq, p, &flags);
++
++	stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
++	tlb_migrate_finish(p->mm);
++	mutex_unlock(&sched_down_mutex);
++
++	return 1;
+ }
+ 
+ /*
+@@ -4738,7 +5033,7 @@
+ 	do_set_cpus_allowed(p, new_mask);
+ 
+ 	/* Can the task run on the task's current CPU? If so, we're done */
+-	if (cpumask_test_cpu(task_cpu(p), new_mask))
++	if (cpumask_test_cpu(task_cpu(p), new_mask) || __migrate_disabled(p))
+ 		goto out;
+ 
+ 	dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
+@@ -4878,6 +5173,8 @@
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+ 
++static DEFINE_PER_CPU(struct mm_struct *, idle_last_mm);
++
+ /*
+  * Ensures that the idle task is using init_mm right before its cpu goes
+  * offline.
+@@ -4892,7 +5189,11 @@
+ 		switch_mm(mm, &init_mm, current);
+ 		finish_arch_post_lock_switch();
+ 	}
+-	mmdrop(mm);
++	/*
++	 * Defer the cleanup to an alive cpu. On RT we can neither
++	 * call mmdrop() nor mmdrop_delayed() from here.
++	 */
++	per_cpu(idle_last_mm, smp_processor_id()) = mm;
+ }
+ 
+ /*
+@@ -5235,6 +5536,10 @@
+ 
+ 	case CPU_DEAD:
+ 		calc_load_migrate(rq);
++		if (per_cpu(idle_last_mm, cpu)) {
++			mmdrop(per_cpu(idle_last_mm, cpu));
++			per_cpu(idle_last_mm, cpu) = NULL;
++		}
+ 		break;
+ #endif
+ 	}
+@@ -7176,7 +7481,8 @@
+ #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+ static inline int preempt_count_equals(int preempt_offset)
+ {
+-	int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
++	int nested = (preempt_count() & ~PREEMPT_ACTIVE) +
++		sched_rcu_preempt_depth();
+ 
+ 	return (nested == preempt_offset);
+ }
+diff -Nur linux-3.18.8.orig/kernel/sched/cputime.c linux-3.18.8/kernel/sched/cputime.c
+--- linux-3.18.8.orig/kernel/sched/cputime.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/cputime.c	2015-03-03 08:05:18.000000000 +0100
+@@ -675,37 +675,45 @@
+ 
+ void vtime_account_system(struct task_struct *tsk)
+ {
+-	write_seqlock(&tsk->vtime_seqlock);
++	raw_spin_lock(&tsk->vtime_lock);
++	write_seqcount_begin(&tsk->vtime_seq);
+ 	__vtime_account_system(tsk);
+-	write_sequnlock(&tsk->vtime_seqlock);
++	write_seqcount_end(&tsk->vtime_seq);
++	raw_spin_unlock(&tsk->vtime_lock);
+ }
+ 
+ void vtime_gen_account_irq_exit(struct task_struct *tsk)
+ {
+-	write_seqlock(&tsk->vtime_seqlock);
++	raw_spin_lock(&tsk->vtime_lock);
++	write_seqcount_begin(&tsk->vtime_seq);
+ 	__vtime_account_system(tsk);
+ 	if (context_tracking_in_user())
+ 		tsk->vtime_snap_whence = VTIME_USER;
+-	write_sequnlock(&tsk->vtime_seqlock);
++	write_seqcount_end(&tsk->vtime_seq);
++	raw_spin_unlock(&tsk->vtime_lock);
+ }
+ 
+ void vtime_account_user(struct task_struct *tsk)
+ {
+ 	cputime_t delta_cpu;
+ 
+-	write_seqlock(&tsk->vtime_seqlock);
++	raw_spin_lock(&tsk->vtime_lock);
++	write_seqcount_begin(&tsk->vtime_seq);
+ 	delta_cpu = get_vtime_delta(tsk);
+ 	tsk->vtime_snap_whence = VTIME_SYS;
+ 	account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
+-	write_sequnlock(&tsk->vtime_seqlock);
++	write_seqcount_end(&tsk->vtime_seq);
++	raw_spin_unlock(&tsk->vtime_lock);
+ }
+ 
+ void vtime_user_enter(struct task_struct *tsk)
+ {
+-	write_seqlock(&tsk->vtime_seqlock);
++	raw_spin_lock(&tsk->vtime_lock);
++	write_seqcount_begin(&tsk->vtime_seq);
+ 	__vtime_account_system(tsk);
+ 	tsk->vtime_snap_whence = VTIME_USER;
+-	write_sequnlock(&tsk->vtime_seqlock);
++	write_seqcount_end(&tsk->vtime_seq);
++	raw_spin_unlock(&tsk->vtime_lock);
+ }
+ 
+ void vtime_guest_enter(struct task_struct *tsk)
+@@ -717,19 +725,23 @@
+ 	 * synchronization against the reader (task_gtime())
+ 	 * that can thus safely catch up with a tickless delta.
+ 	 */
+-	write_seqlock(&tsk->vtime_seqlock);
++	raw_spin_lock(&tsk->vtime_lock);
++	write_seqcount_begin(&tsk->vtime_seq);
+ 	__vtime_account_system(tsk);
+ 	current->flags |= PF_VCPU;
+-	write_sequnlock(&tsk->vtime_seqlock);
++	write_seqcount_end(&tsk->vtime_seq);
++	raw_spin_unlock(&tsk->vtime_lock);
+ }
+ EXPORT_SYMBOL_GPL(vtime_guest_enter);
+ 
+ void vtime_guest_exit(struct task_struct *tsk)
+ {
+-	write_seqlock(&tsk->vtime_seqlock);
++	raw_spin_lock(&tsk->vtime_lock);
++	write_seqcount_begin(&tsk->vtime_seq);
+ 	__vtime_account_system(tsk);
+ 	current->flags &= ~PF_VCPU;
+-	write_sequnlock(&tsk->vtime_seqlock);
++	write_seqcount_end(&tsk->vtime_seq);
++	raw_spin_unlock(&tsk->vtime_lock);
+ }
+ EXPORT_SYMBOL_GPL(vtime_guest_exit);
+ 
+@@ -742,24 +754,30 @@
+ 
+ void arch_vtime_task_switch(struct task_struct *prev)
+ {
+-	write_seqlock(&prev->vtime_seqlock);
++	raw_spin_lock(&prev->vtime_lock);
++	write_seqcount_begin(&prev->vtime_seq);
+ 	prev->vtime_snap_whence = VTIME_SLEEPING;
+-	write_sequnlock(&prev->vtime_seqlock);
++	write_seqcount_end(&prev->vtime_seq);
++	raw_spin_unlock(&prev->vtime_lock);
+ 
+-	write_seqlock(&current->vtime_seqlock);
++	raw_spin_lock(&current->vtime_lock);
++	write_seqcount_begin(&current->vtime_seq);
+ 	current->vtime_snap_whence = VTIME_SYS;
+ 	current->vtime_snap = sched_clock_cpu(smp_processor_id());
+-	write_sequnlock(&current->vtime_seqlock);
++	write_seqcount_end(&current->vtime_seq);
++	raw_spin_unlock(&current->vtime_lock);
+ }
+ 
+ void vtime_init_idle(struct task_struct *t, int cpu)
+ {
+ 	unsigned long flags;
+ 
+-	write_seqlock_irqsave(&t->vtime_seqlock, flags);
++	raw_spin_lock_irqsave(&t->vtime_lock, flags);
++	write_seqcount_begin(&t->vtime_seq);
+ 	t->vtime_snap_whence = VTIME_SYS;
+ 	t->vtime_snap = sched_clock_cpu(cpu);
+-	write_sequnlock_irqrestore(&t->vtime_seqlock, flags);
++	write_seqcount_end(&t->vtime_seq);
++	raw_spin_unlock_irqrestore(&t->vtime_lock, flags);
+ }
+ 
+ cputime_t task_gtime(struct task_struct *t)
+@@ -768,13 +786,13 @@
+ 	cputime_t gtime;
+ 
+ 	do {
+-		seq = read_seqbegin(&t->vtime_seqlock);
++		seq = read_seqcount_begin(&t->vtime_seq);
+ 
+ 		gtime = t->gtime;
+ 		if (t->flags & PF_VCPU)
+ 			gtime += vtime_delta(t);
+ 
+-	} while (read_seqretry(&t->vtime_seqlock, seq));
++	} while (read_seqcount_retry(&t->vtime_seq, seq));
+ 
+ 	return gtime;
+ }
+@@ -797,7 +815,7 @@
+ 		*udelta = 0;
+ 		*sdelta = 0;
+ 
+-		seq = read_seqbegin(&t->vtime_seqlock);
++		seq = read_seqcount_begin(&t->vtime_seq);
+ 
+ 		if (u_dst)
+ 			*u_dst = *u_src;
+@@ -821,7 +839,7 @@
+ 			if (t->vtime_snap_whence == VTIME_SYS)
+ 				*sdelta = delta;
+ 		}
+-	} while (read_seqretry(&t->vtime_seqlock, seq));
++	} while (read_seqcount_retry(&t->vtime_seq, seq));
+ }
+ 
+ 
+diff -Nur linux-3.18.8.orig/kernel/sched/deadline.c linux-3.18.8/kernel/sched/deadline.c
+--- linux-3.18.8.orig/kernel/sched/deadline.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/deadline.c	2015-03-03 08:05:18.000000000 +0100
+@@ -570,6 +570,7 @@
+ 
+ 	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ 	timer->function = dl_task_timer;
++	timer->irqsafe = 1;
+ }
+ 
+ static
+diff -Nur linux-3.18.8.orig/kernel/sched/debug.c linux-3.18.8/kernel/sched/debug.c
+--- linux-3.18.8.orig/kernel/sched/debug.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/debug.c	2015-03-03 08:05:18.000000000 +0100
+@@ -256,6 +256,9 @@
+ 	P(rt_throttled);
+ 	PN(rt_time);
+ 	PN(rt_runtime);
++#ifdef CONFIG_SMP
++	P(rt_nr_migratory);
++#endif
+ 
+ #undef PN
+ #undef P
+@@ -634,6 +637,10 @@
+ #endif
+ 	P(policy);
+ 	P(prio);
++#ifdef CONFIG_PREEMPT_RT_FULL
++	P(migrate_disable);
++#endif
++	P(nr_cpus_allowed);
+ #undef PN
+ #undef __PN
+ #undef P
+diff -Nur linux-3.18.8.orig/kernel/sched/fair.c linux-3.18.8/kernel/sched/fair.c
+--- linux-3.18.8.orig/kernel/sched/fair.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/fair.c	2015-03-03 08:05:18.000000000 +0100
+@@ -2951,7 +2951,7 @@
+ 	ideal_runtime = sched_slice(cfs_rq, curr);
+ 	delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ 	if (delta_exec > ideal_runtime) {
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ 		/*
+ 		 * The current task ran long enough, ensure it doesn't get
+ 		 * re-elected due to buddy favours.
+@@ -2975,7 +2975,7 @@
+ 		return;
+ 
+ 	if (delta > ideal_runtime)
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ }
+ 
+ static void
+@@ -3115,7 +3115,7 @@
+ 	 * validating it and just reschedule.
+ 	 */
+ 	if (queued) {
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ 		return;
+ 	}
+ 	/*
+@@ -3306,7 +3306,7 @@
+ 	 * hierarchy can be throttled
+ 	 */
+ 	if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ }
+ 
+ static __always_inline
+@@ -3925,7 +3925,7 @@
+ 
+ 		if (delta < 0) {
+ 			if (rq->curr == p)
+-				resched_curr(rq);
++				resched_curr_lazy(rq);
+ 			return;
+ 		}
+ 		hrtick_start(rq, delta);
+@@ -4792,7 +4792,7 @@
+ 	return;
+ 
+ preempt:
+-	resched_curr(rq);
++	resched_curr_lazy(rq);
+ 	/*
+ 	 * Only set the backward buddy when the current task is still
+ 	 * on the rq. This can happen when a wakeup gets interleaved
+@@ -7576,7 +7576,7 @@
+ 		 * 'current' within the tree based on its new key value.
+ 		 */
+ 		swap(curr->vruntime, se->vruntime);
+-		resched_curr(rq);
++		resched_curr_lazy(rq);
+ 	}
+ 
+ 	se->vruntime -= cfs_rq->min_vruntime;
+@@ -7601,7 +7601,7 @@
+ 	 */
+ 	if (rq->curr == p) {
+ 		if (p->prio > oldprio)
+-			resched_curr(rq);
++			resched_curr_lazy(rq);
+ 	} else
+ 		check_preempt_curr(rq, p, 0);
+ }
+diff -Nur linux-3.18.8.orig/kernel/sched/features.h linux-3.18.8/kernel/sched/features.h
+--- linux-3.18.8.orig/kernel/sched/features.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/features.h	2015-03-03 08:05:18.000000000 +0100
+@@ -50,12 +50,18 @@
+  */
+ SCHED_FEAT(NONTASK_CAPACITY, true)
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++SCHED_FEAT(TTWU_QUEUE, false)
++# ifdef CONFIG_PREEMPT_LAZY
++SCHED_FEAT(PREEMPT_LAZY, true)
++# endif
++#else
+ /*
+  * Queue remote wakeups on the target CPU and process them
+  * using the scheduler IPI. Reduces rq->lock contention/bounces.
+  */
+ SCHED_FEAT(TTWU_QUEUE, true)
+-
++#endif
+ SCHED_FEAT(FORCE_SD_OVERLAP, false)
+ SCHED_FEAT(RT_RUNTIME_SHARE, true)
+ SCHED_FEAT(LB_MIN, false)
+diff -Nur linux-3.18.8.orig/kernel/sched/Makefile linux-3.18.8/kernel/sched/Makefile
+--- linux-3.18.8.orig/kernel/sched/Makefile	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/Makefile	2015-03-03 08:05:18.000000000 +0100
+@@ -13,7 +13,7 @@
+ 
+ obj-y += core.o proc.o clock.o cputime.o
+ obj-y += idle_task.o fair.o rt.o deadline.o stop_task.o
+-obj-y += wait.o completion.o idle.o
++obj-y += wait.o wait-simple.o work-simple.o completion.o idle.o
+ obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o
+ obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
+ obj-$(CONFIG_SCHEDSTATS) += stats.o
+diff -Nur linux-3.18.8.orig/kernel/sched/rt.c linux-3.18.8/kernel/sched/rt.c
+--- linux-3.18.8.orig/kernel/sched/rt.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/rt.c	2015-03-03 08:05:18.000000000 +0100
+@@ -43,6 +43,7 @@
+ 
+ 	hrtimer_init(&rt_b->rt_period_timer,
+ 			CLOCK_MONOTONIC, HRTIMER_MODE_REL);
++	rt_b->rt_period_timer.irqsafe = 1;
+ 	rt_b->rt_period_timer.function = sched_rt_period_timer;
+ }
+ 
+diff -Nur linux-3.18.8.orig/kernel/sched/sched.h linux-3.18.8/kernel/sched/sched.h
+--- linux-3.18.8.orig/kernel/sched/sched.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/sched/sched.h	2015-03-03 08:05:18.000000000 +0100
+@@ -1018,6 +1018,7 @@
+ #define WF_SYNC		0x01		/* waker goes to sleep after wakeup */
+ #define WF_FORK		0x02		/* child wakeup after fork */
+ #define WF_MIGRATED	0x4		/* internal use, task got migrated */
++#define WF_LOCK_SLEEPER	0x08		/* wakeup spinlock "sleeper" */
+ 
+ /*
+  * To aid in avoiding the subversion of "niceness" due to uneven distribution
+@@ -1210,6 +1211,15 @@
+ extern void resched_curr(struct rq *rq);
+ extern void resched_cpu(int cpu);
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++extern void resched_curr_lazy(struct rq *rq);
++#else
++static inline void resched_curr_lazy(struct rq *rq)
++{
++	resched_curr(rq);
++}
++#endif
++
+ extern struct rt_bandwidth def_rt_bandwidth;
+ extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
+ 
+diff -Nur linux-3.18.8.orig/kernel/sched/wait-simple.c linux-3.18.8/kernel/sched/wait-simple.c
+--- linux-3.18.8.orig/kernel/sched/wait-simple.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/kernel/sched/wait-simple.c	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,115 @@
++/*
++ * Simple waitqueues without fancy flags and callbacks
++ *
++ * (C) 2011 Thomas Gleixner <tglx@linutronix.de>
++ *
++ * Based on kernel/wait.c
++ *
++ * For licencing details see kernel-base/COPYING
++ */
++#include <linux/init.h>
++#include <linux/export.h>
++#include <linux/sched.h>
++#include <linux/wait-simple.h>
++
++/* Adds w to head->list. Must be called with head->lock locked. */
++static inline void __swait_enqueue(struct swait_head *head, struct swaiter *w)
++{
++	list_add(&w->node, &head->list);
++	/* We can't let the condition leak before the setting of head */
++	smp_mb();
++}
++
++/* Removes w from head->list. Must be called with head->lock locked. */
++static inline void __swait_dequeue(struct swaiter *w)
++{
++	list_del_init(&w->node);
++}
++
++void __init_swait_head(struct swait_head *head, struct lock_class_key *key)
++{
++	raw_spin_lock_init(&head->lock);
++	lockdep_set_class(&head->lock, key);
++	INIT_LIST_HEAD(&head->list);
++}
++EXPORT_SYMBOL(__init_swait_head);
++
++void swait_prepare_locked(struct swait_head *head, struct swaiter *w)
++{
++	w->task = current;
++	if (list_empty(&w->node))
++		__swait_enqueue(head, w);
++}
++
++void swait_prepare(struct swait_head *head, struct swaiter *w, int state)
++{
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&head->lock, flags);
++	swait_prepare_locked(head, w);
++	__set_current_state(state);
++	raw_spin_unlock_irqrestore(&head->lock, flags);
++}
++EXPORT_SYMBOL(swait_prepare);
++
++void swait_finish_locked(struct swait_head *head, struct swaiter *w)
++{
++	__set_current_state(TASK_RUNNING);
++	if (w->task)
++		__swait_dequeue(w);
++}
++
++void swait_finish(struct swait_head *head, struct swaiter *w)
++{
++	unsigned long flags;
++
++	__set_current_state(TASK_RUNNING);
++	if (w->task) {
++		raw_spin_lock_irqsave(&head->lock, flags);
++		__swait_dequeue(w);
++		raw_spin_unlock_irqrestore(&head->lock, flags);
++	}
++}
++EXPORT_SYMBOL(swait_finish);
++
++unsigned int
++__swait_wake_locked(struct swait_head *head, unsigned int state, unsigned int num)
++{
++	struct swaiter *curr, *next;
++	int woken = 0;
++
++	list_for_each_entry_safe(curr, next, &head->list, node) {
++		if (wake_up_state(curr->task, state)) {
++			__swait_dequeue(curr);
++			/*
++			 * The waiting task can free the waiter as
++			 * soon as curr->task = NULL is written,
++			 * without taking any locks. A memory barrier
++			 * is required here to prevent the following
++			 * store to curr->task from getting ahead of
++			 * the dequeue operation.
++			 */
++			smp_wmb();
++			curr->task = NULL;
++			if (++woken == num)
++				break;
++		}
++	}
++	return woken;
++}
++
++unsigned int
++__swait_wake(struct swait_head *head, unsigned int state, unsigned int num)
++{
++	unsigned long flags;
++	int woken;
++
++	if (!swaitqueue_active(head))
++		return 0;
++
++	raw_spin_lock_irqsave(&head->lock, flags);
++	woken = __swait_wake_locked(head, state, num);
++	raw_spin_unlock_irqrestore(&head->lock, flags);
++	return woken;
++}
++EXPORT_SYMBOL(__swait_wake);
+diff -Nur linux-3.18.8.orig/kernel/sched/work-simple.c linux-3.18.8/kernel/sched/work-simple.c
+--- linux-3.18.8.orig/kernel/sched/work-simple.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/kernel/sched/work-simple.c	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,176 @@
++/*
++ * Copyright (C) 2014 BMW Car IT GmbH, Daniel Wagner daniel.wagner@bmw-carit.de
++ *
++ * Provides a framework for enqueuing callbacks from irq context
++ * PREEMPT_RT_FULL safe. The callbacks are executed in kthread context.
++ */
++
++#include <linux/wait-simple.h>
++#include <linux/work-simple.h>
++#include <linux/kthread.h>
++#include <linux/slab.h>
++#include <linux/spinlock.h>
++
++#define SWORK_EVENT_PENDING     (1 << 0)
++
++static DEFINE_MUTEX(worker_mutex);
++static struct sworker *glob_worker;
++
++struct sworker {
++	struct list_head events;
++	struct swait_head wq;
++
++	raw_spinlock_t lock;
++
++	struct task_struct *task;
++	int refs;
++};
++
++static bool swork_readable(struct sworker *worker)
++{
++	bool r;
++
++	if (kthread_should_stop())
++		return true;
++
++	raw_spin_lock(&worker->lock);
++	r = !list_empty(&worker->events);
++	raw_spin_unlock(&worker->lock);
++
++	return r;
++}
++
++static int swork_kthread(void *arg)
++{
++	struct sworker *worker = arg;
++
++	pr_info("swork_kthread enter\n");
++
++	for (;;) {
++		swait_event_interruptible(worker->wq,
++					swork_readable(worker));
++		if (kthread_should_stop())
++			break;
++
++		raw_spin_lock(&worker->lock);
++		while (!list_empty(&worker->events)) {
++			struct swork_event *sev;
++
++			sev = list_first_entry(&worker->events,
++					struct swork_event, item);
++			list_del(&sev->item);
++			raw_spin_unlock(&worker->lock);
++
++			WARN_ON_ONCE(!test_and_clear_bit(SWORK_EVENT_PENDING,
++							 &sev->flags));
++			sev->func(sev);
++			raw_spin_lock(&worker->lock);
++		}
++		raw_spin_unlock(&worker->lock);
++	}
++
++	pr_info("swork_kthread exit\n");
++	return 0;
++}
++
++static struct sworker *swork_create(void)
++{
++	struct sworker *worker;
++
++	worker = kzalloc(sizeof(*worker), GFP_KERNEL);
++	if (!worker)
++		return ERR_PTR(-ENOMEM);
++
++	INIT_LIST_HEAD(&worker->events);
++	raw_spin_lock_init(&worker->lock);
++	init_swait_head(&worker->wq);
++
++	worker->task = kthread_run(swork_kthread, worker, "kswork");
++	if (IS_ERR(worker->task)) {
++		kfree(worker);
++		return ERR_PTR(-ENOMEM);
++	}
++
++	return worker;
++}
++
++static void swork_destroy(struct sworker *worker)
++{
++	kthread_stop(worker->task);
++
++	WARN_ON(!list_empty(&worker->events));
++	kfree(worker);
++}
++
++/**
++ * swork_queue - queue swork
++ *
++ * Returns %false if @work was already on a queue, %true otherwise.
++ *
++ * The work is queued and processed on a random CPU
++ */
++bool swork_queue(struct swork_event *sev)
++{
++	if (test_and_set_bit(SWORK_EVENT_PENDING, &sev->flags))
++		return false;
++
++	WARN_ON(irqs_disabled());
++
++	raw_spin_lock(&glob_worker->lock);
++	list_add_tail(&sev->item, &glob_worker->events);
++	raw_spin_unlock(&glob_worker->lock);
++
++	swait_wake(&glob_worker->wq);
++	return true;
++}
++EXPORT_SYMBOL_GPL(swork_queue);
++
++/**
++ * swork_get - get an instance of the sworker
++ *
++ * Returns an negative error code if the initialization if the worker did not
++ * work, %0 otherwise.
++ *
++ */
++int swork_get(void)
++{
++	struct sworker *worker;
++
++	mutex_lock(&worker_mutex);
++	if (!glob_worker) {
++		worker = swork_create();
++		if (IS_ERR(worker)) {
++			mutex_unlock(&worker_mutex);
++			return -ENOMEM;
++		}
++
++		glob_worker = worker;
++	}
++
++	glob_worker->refs++;
++	mutex_unlock(&worker_mutex);
++
++	return 0;
++}
++EXPORT_SYMBOL_GPL(swork_get);
++
++/**
++ * swork_put - puts an instance of the sworker
++ *
++ * Will destroy the sworker thread. This function must not be called until all
++ * queued events have been completed.
++ */
++void swork_put(void)
++{
++	mutex_lock(&worker_mutex);
++
++	glob_worker->refs--;
++	if (glob_worker->refs > 0)
++		goto out;
++
++	swork_destroy(glob_worker);
++	glob_worker = NULL;
++out:
++	mutex_unlock(&worker_mutex);
++}
++EXPORT_SYMBOL_GPL(swork_put);
+diff -Nur linux-3.18.8.orig/kernel/signal.c linux-3.18.8/kernel/signal.c
+--- linux-3.18.8.orig/kernel/signal.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/signal.c	2015-03-03 08:05:18.000000000 +0100
+@@ -14,6 +14,7 @@
+ #include <linux/export.h>
+ #include <linux/init.h>
+ #include <linux/sched.h>
++#include <linux/sched/rt.h>
+ #include <linux/fs.h>
+ #include <linux/tty.h>
+ #include <linux/binfmts.h>
+@@ -352,13 +353,45 @@
+ 	return false;
+ }
+ 
++#ifdef __HAVE_ARCH_CMPXCHG
++static inline struct sigqueue *get_task_cache(struct task_struct *t)
++{
++	struct sigqueue *q = t->sigqueue_cache;
++
++	if (cmpxchg(&t->sigqueue_cache, q, NULL) != q)
++		return NULL;
++	return q;
++}
++
++static inline int put_task_cache(struct task_struct *t, struct sigqueue *q)
++{
++	if (cmpxchg(&t->sigqueue_cache, NULL, q) == NULL)
++		return 0;
++	return 1;
++}
++
++#else
++
++static inline struct sigqueue *get_task_cache(struct task_struct *t)
++{
++	return NULL;
++}
++
++static inline int put_task_cache(struct task_struct *t, struct sigqueue *q)
++{
++	return 1;
++}
++
++#endif
++
+ /*
+  * allocate a new signal queue record
+  * - this may be called without locks if and only if t == current, otherwise an
+  *   appropriate lock must be held to stop the target task from exiting
+  */
+ static struct sigqueue *
+-__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
++__sigqueue_do_alloc(int sig, struct task_struct *t, gfp_t flags,
++		    int override_rlimit, int fromslab)
+ {
+ 	struct sigqueue *q = NULL;
+ 	struct user_struct *user;
+@@ -375,7 +408,10 @@
+ 	if (override_rlimit ||
+ 	    atomic_read(&user->sigpending) <=
+ 			task_rlimit(t, RLIMIT_SIGPENDING)) {
+-		q = kmem_cache_alloc(sigqueue_cachep, flags);
++		if (!fromslab)
++			q = get_task_cache(t);
++		if (!q)
++			q = kmem_cache_alloc(sigqueue_cachep, flags);
+ 	} else {
+ 		print_dropped_signal(sig);
+ 	}
+@@ -392,6 +428,13 @@
+ 	return q;
+ }
+ 
++static struct sigqueue *
++__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags,
++		 int override_rlimit)
++{
++	return __sigqueue_do_alloc(sig, t, flags, override_rlimit, 0);
++}
++
+ static void __sigqueue_free(struct sigqueue *q)
+ {
+ 	if (q->flags & SIGQUEUE_PREALLOC)
+@@ -401,6 +444,21 @@
+ 	kmem_cache_free(sigqueue_cachep, q);
+ }
+ 
++static void sigqueue_free_current(struct sigqueue *q)
++{
++	struct user_struct *up;
++
++	if (q->flags & SIGQUEUE_PREALLOC)
++		return;
++
++	up = q->user;
++	if (rt_prio(current->normal_prio) && !put_task_cache(current, q)) {
++		atomic_dec(&up->sigpending);
++		free_uid(up);
++	} else
++		  __sigqueue_free(q);
++}
++
+ void flush_sigqueue(struct sigpending *queue)
+ {
+ 	struct sigqueue *q;
+@@ -414,6 +472,21 @@
+ }
+ 
+ /*
++ * Called from __exit_signal. Flush tsk->pending and
++ * tsk->sigqueue_cache
++ */
++void flush_task_sigqueue(struct task_struct *tsk)
++{
++	struct sigqueue *q;
++
++	flush_sigqueue(&tsk->pending);
++
++	q = get_task_cache(tsk);
++	if (q)
++		kmem_cache_free(sigqueue_cachep, q);
++}
++
++/*
+  * Flush all pending signals for a task.
+  */
+ void __flush_signals(struct task_struct *t)
+@@ -565,7 +638,7 @@
+ still_pending:
+ 		list_del_init(&first->list);
+ 		copy_siginfo(info, &first->info);
+-		__sigqueue_free(first);
++		sigqueue_free_current(first);
+ 	} else {
+ 		/*
+ 		 * Ok, it wasn't in the queue.  This must be
+@@ -611,6 +684,8 @@
+ {
+ 	int signr;
+ 
++	WARN_ON_ONCE(tsk != current);
++
+ 	/* We only dequeue private signals from ourselves, we don't let
+ 	 * signalfd steal them
+ 	 */
+@@ -1207,8 +1282,8 @@
+  * We don't want to have recursive SIGSEGV's etc, for example,
+  * that is why we also clear SIGNAL_UNKILLABLE.
+  */
+-int
+-force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
++static int
++do_force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+ {
+ 	unsigned long int flags;
+ 	int ret, blocked, ignored;
+@@ -1233,6 +1308,39 @@
+ 	return ret;
+ }
+ 
++int force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
++{
++/*
++ * On some archs, PREEMPT_RT has to delay sending a signal from a trap
++ * since it can not enable preemption, and the signal code's spin_locks
++ * turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME which will
++ * send the signal on exit of the trap.
++ */
++#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
++	if (in_atomic()) {
++		if (WARN_ON_ONCE(t != current))
++			return 0;
++		if (WARN_ON_ONCE(t->forced_info.si_signo))
++			return 0;
++
++		if (is_si_special(info)) {
++			WARN_ON_ONCE(info != SEND_SIG_PRIV);
++			t->forced_info.si_signo = sig;
++			t->forced_info.si_errno = 0;
++			t->forced_info.si_code = SI_KERNEL;
++			t->forced_info.si_pid = 0;
++			t->forced_info.si_uid = 0;
++		} else {
++			t->forced_info = *info;
++		}
++
++		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
++		return 0;
++	}
++#endif
++	return do_force_sig_info(sig, info, t);
++}
++
+ /*
+  * Nuke all other threads in the group.
+  */
+@@ -1267,12 +1375,12 @@
+ 		 * Disable interrupts early to avoid deadlocks.
+ 		 * See rcu_read_unlock() comment header for details.
+ 		 */
+-		local_irq_save(*flags);
++		local_irq_save_nort(*flags);
+ 		rcu_read_lock();
+ 		sighand = rcu_dereference(tsk->sighand);
+ 		if (unlikely(sighand == NULL)) {
+ 			rcu_read_unlock();
+-			local_irq_restore(*flags);
++			local_irq_restore_nort(*flags);
+ 			break;
+ 		}
+ 
+@@ -1283,7 +1391,7 @@
+ 		}
+ 		spin_unlock(&sighand->siglock);
+ 		rcu_read_unlock();
+-		local_irq_restore(*flags);
++		local_irq_restore_nort(*flags);
+ 	}
+ 
+ 	return sighand;
+@@ -1528,7 +1636,8 @@
+  */
+ struct sigqueue *sigqueue_alloc(void)
+ {
+-	struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
++	/* Preallocated sigqueue objects always from the slabcache ! */
++	struct sigqueue *q = __sigqueue_do_alloc(-1, current, GFP_KERNEL, 0, 1);
+ 
+ 	if (q)
+ 		q->flags |= SIGQUEUE_PREALLOC;
+@@ -1889,15 +1998,7 @@
+ 		if (gstop_done && ptrace_reparented(current))
+ 			do_notify_parent_cldstop(current, false, why);
+ 
+-		/*
+-		 * Don't want to allow preemption here, because
+-		 * sys_ptrace() needs this task to be inactive.
+-		 *
+-		 * XXX: implement read_unlock_no_resched().
+-		 */
+-		preempt_disable();
+ 		read_unlock(&tasklist_lock);
+-		preempt_enable_no_resched();
+ 		freezable_schedule();
+ 	} else {
+ 		/*
+diff -Nur linux-3.18.8.orig/kernel/softirq.c linux-3.18.8/kernel/softirq.c
+--- linux-3.18.8.orig/kernel/softirq.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/softirq.c	2015-03-03 08:05:18.000000000 +0100
+@@ -21,10 +21,12 @@
+ #include <linux/freezer.h>
+ #include <linux/kthread.h>
+ #include <linux/rcupdate.h>
++#include <linux/delay.h>
+ #include <linux/ftrace.h>
+ #include <linux/smp.h>
+ #include <linux/smpboot.h>
+ #include <linux/tick.h>
++#include <linux/locallock.h>
+ #include <linux/irq.h>
+ 
+ #define CREATE_TRACE_POINTS
+@@ -62,6 +64,98 @@
+ 	"TASKLET", "SCHED", "HRTIMER", "RCU"
+ };
+ 
++#ifdef CONFIG_NO_HZ_COMMON
++# ifdef CONFIG_PREEMPT_RT_FULL
++
++struct softirq_runner {
++	struct task_struct *runner[NR_SOFTIRQS];
++};
++
++static DEFINE_PER_CPU(struct softirq_runner, softirq_runners);
++
++static inline void softirq_set_runner(unsigned int sirq)
++{
++	struct softirq_runner *sr = &__get_cpu_var(softirq_runners);
++
++	sr->runner[sirq] = current;
++}
++
++static inline void softirq_clr_runner(unsigned int sirq)
++{
++	struct softirq_runner *sr = &__get_cpu_var(softirq_runners);
++
++	sr->runner[sirq] = NULL;
++}
++
++/*
++ * On preempt-rt a softirq running context might be blocked on a
++ * lock. There might be no other runnable task on this CPU because the
++ * lock owner runs on some other CPU. So we have to go into idle with
++ * the pending bit set. Therefor we need to check this otherwise we
++ * warn about false positives which confuses users and defeats the
++ * whole purpose of this test.
++ *
++ * This code is called with interrupts disabled.
++ */
++void softirq_check_pending_idle(void)
++{
++	static int rate_limit;
++	struct softirq_runner *sr = &__get_cpu_var(softirq_runners);
++	u32 warnpending;
++	int i;
++
++	if (rate_limit >= 10)
++		return;
++
++	warnpending = local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK;
++	for (i = 0; i < NR_SOFTIRQS; i++) {
++		struct task_struct *tsk = sr->runner[i];
++
++		/*
++		 * The wakeup code in rtmutex.c wakes up the task
++		 * _before_ it sets pi_blocked_on to NULL under
++		 * tsk->pi_lock. So we need to check for both: state
++		 * and pi_blocked_on.
++		 */
++		if (tsk) {
++			raw_spin_lock(&tsk->pi_lock);
++			if (tsk->pi_blocked_on || tsk->state == TASK_RUNNING) {
++				/* Clear all bits pending in that task */
++				warnpending &= ~(tsk->softirqs_raised);
++				warnpending &= ~(1 << i);
++			}
++			raw_spin_unlock(&tsk->pi_lock);
++		}
++	}
++
++	if (warnpending) {
++		printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
++		       warnpending);
++		rate_limit++;
++	}
++}
++# else
++/*
++ * On !PREEMPT_RT we just printk rate limited:
++ */
++void softirq_check_pending_idle(void)
++{
++	static int rate_limit;
++
++	if (rate_limit < 10 &&
++			(local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) {
++		printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
++		       local_softirq_pending());
++		rate_limit++;
++	}
++}
++# endif
++
++#else /* !CONFIG_NO_HZ_COMMON */
++static inline void softirq_set_runner(unsigned int sirq) { }
++static inline void softirq_clr_runner(unsigned int sirq) { }
++#endif
++
+ /*
+  * we cannot loop indefinitely here to avoid userspace starvation,
+  * but we also don't want to introduce a worst case 1/HZ latency
+@@ -77,6 +171,70 @@
+ 		wake_up_process(tsk);
+ }
+ 
++static void handle_softirq(unsigned int vec_nr)
++{
++	struct softirq_action *h = softirq_vec + vec_nr;
++	int prev_count;
++
++	prev_count = preempt_count();
++
++	kstat_incr_softirqs_this_cpu(vec_nr);
++
++	trace_softirq_entry(vec_nr);
++	h->action(h);
++	trace_softirq_exit(vec_nr);
++	if (unlikely(prev_count != preempt_count())) {
++		pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x?\n",
++		       vec_nr, softirq_to_name[vec_nr], h->action,
++		       prev_count, preempt_count());
++		preempt_count_set(prev_count);
++	}
++}
++
++#ifndef CONFIG_PREEMPT_RT_FULL
++static inline int ksoftirqd_softirq_pending(void)
++{
++	return local_softirq_pending();
++}
++
++static void handle_pending_softirqs(u32 pending, int need_rcu_bh_qs)
++{
++	struct softirq_action *h = softirq_vec;
++	int softirq_bit;
++
++	local_irq_enable();
++
++	h = softirq_vec;
++
++	while ((softirq_bit = ffs(pending))) {
++		unsigned int vec_nr;
++
++		h += softirq_bit - 1;
++		vec_nr = h - softirq_vec;
++		handle_softirq(vec_nr);
++
++		h++;
++		pending >>= softirq_bit;
++	}
++
++	if (need_rcu_bh_qs)
++		rcu_bh_qs();
++	local_irq_disable();
++}
++
++static void run_ksoftirqd(unsigned int cpu)
++{
++	local_irq_disable();
++	if (ksoftirqd_softirq_pending()) {
++		__do_softirq();
++		rcu_note_context_switch(cpu);
++		local_irq_enable();
++		cond_resched();
++		return;
++	}
++	local_irq_enable();
++}
++
+ /*
+  * preempt_count and SOFTIRQ_OFFSET usage:
+  * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
+@@ -228,10 +386,8 @@
+ 	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
+ 	unsigned long old_flags = current->flags;
+ 	int max_restart = MAX_SOFTIRQ_RESTART;
+-	struct softirq_action *h;
+ 	bool in_hardirq;
+ 	__u32 pending;
+-	int softirq_bit;
+ 
+ 	/*
+ 	 * Mask out PF_MEMALLOC s current task context is borrowed for the
+@@ -250,36 +406,7 @@
+ 	/* Reset the pending bitmask before enabling irqs */
+ 	set_softirq_pending(0);
+ 
+-	local_irq_enable();
+-
+-	h = softirq_vec;
+-
+-	while ((softirq_bit = ffs(pending))) {
+-		unsigned int vec_nr;
+-		int prev_count;
+-
+-		h += softirq_bit - 1;
+-
+-		vec_nr = h - softirq_vec;
+-		prev_count = preempt_count();
+-
+-		kstat_incr_softirqs_this_cpu(vec_nr);
+-
+-		trace_softirq_entry(vec_nr);
+-		h->action(h);
+-		trace_softirq_exit(vec_nr);
+-		if (unlikely(prev_count != preempt_count())) {
+-			pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x?\n",
+-			       vec_nr, softirq_to_name[vec_nr], h->action,
+-			       prev_count, preempt_count());
+-			preempt_count_set(prev_count);
+-		}
+-		h++;
+-		pending >>= softirq_bit;
+-	}
+-
+-	rcu_bh_qs();
+-	local_irq_disable();
++	handle_pending_softirqs(pending, 1);
+ 
+ 	pending = local_softirq_pending();
+ 	if (pending) {
+@@ -316,6 +443,285 @@
+ }
+ 
+ /*
++ * This function must run with irqs disabled!
++ */
++void raise_softirq_irqoff(unsigned int nr)
++{
++	__raise_softirq_irqoff(nr);
++
++	/*
++	 * If we're in an interrupt or softirq, we're done
++	 * (this also catches softirq-disabled code). We will
++	 * actually run the softirq once we return from
++	 * the irq or softirq.
++	 *
++	 * Otherwise we wake up ksoftirqd to make sure we
++	 * schedule the softirq soon.
++	 */
++	if (!in_interrupt())
++		wakeup_softirqd();
++}
++
++void __raise_softirq_irqoff(unsigned int nr)
++{
++	trace_softirq_raise(nr);
++	or_softirq_pending(1UL << nr);
++}
++
++static inline void local_bh_disable_nort(void) { local_bh_disable(); }
++static inline void _local_bh_enable_nort(void) { _local_bh_enable(); }
++static void ksoftirqd_set_sched_params(unsigned int cpu) { }
++static void ksoftirqd_clr_sched_params(unsigned int cpu, bool online) { }
++
++#else /* !PREEMPT_RT_FULL */
++
++/*
++ * On RT we serialize softirq execution with a cpu local lock per softirq
++ */
++static DEFINE_PER_CPU(struct local_irq_lock [NR_SOFTIRQS], local_softirq_locks);
++
++void __init softirq_early_init(void)
++{
++	int i;
++
++	for (i = 0; i < NR_SOFTIRQS; i++)
++		local_irq_lock_init(local_softirq_locks[i]);
++}
++
++static void lock_softirq(int which)
++{
++	local_lock(local_softirq_locks[which]);
++}
++
++static void unlock_softirq(int which)
++{
++	local_unlock(local_softirq_locks[which]);
++}
++
++static void do_single_softirq(int which, int need_rcu_bh_qs)
++{
++	unsigned long old_flags = current->flags;
++
++	current->flags &= ~PF_MEMALLOC;
++	vtime_account_irq_enter(current);
++	current->flags |= PF_IN_SOFTIRQ;
++	lockdep_softirq_enter();
++	local_irq_enable();
++	handle_softirq(which);
++	local_irq_disable();
++	lockdep_softirq_exit();
++	current->flags &= ~PF_IN_SOFTIRQ;
++	vtime_account_irq_enter(current);
++	tsk_restore_flags(current, old_flags, PF_MEMALLOC);
++}
++
++/*
++ * Called with interrupts disabled. Process softirqs which were raised
++ * in current context (or on behalf of ksoftirqd).
++ */
++static void do_current_softirqs(int need_rcu_bh_qs)
++{
++	while (current->softirqs_raised) {
++		int i = __ffs(current->softirqs_raised);
++		unsigned int pending, mask = (1U << i);
++
++		current->softirqs_raised &= ~mask;
++		local_irq_enable();
++
++		/*
++		 * If the lock is contended, we boost the owner to
++		 * process the softirq or leave the critical section
++		 * now.
++		 */
++		lock_softirq(i);
++		local_irq_disable();
++		softirq_set_runner(i);
++		/*
++		 * Check with the local_softirq_pending() bits,
++		 * whether we need to process this still or if someone
++		 * else took care of it.
++		 */
++		pending = local_softirq_pending();
++		if (pending & mask) {
++			set_softirq_pending(pending & ~mask);
++			do_single_softirq(i, need_rcu_bh_qs);
++		}
++		softirq_clr_runner(i);
++		unlock_softirq(i);
++		WARN_ON(current->softirq_nestcnt != 1);
++	}
++}
++
++static void __local_bh_disable(void)
++{
++	if (++current->softirq_nestcnt == 1)
++		migrate_disable();
++}
++
++void local_bh_disable(void)
++{
++	__local_bh_disable();
++}
++EXPORT_SYMBOL(local_bh_disable);
++
++void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
++{
++	__local_bh_disable();
++	if (cnt & PREEMPT_CHECK_OFFSET)
++		preempt_disable();
++}
++
++static void __local_bh_enable(void)
++{
++	if (WARN_ON(current->softirq_nestcnt == 0))
++		return;
++
++	local_irq_disable();
++	if (current->softirq_nestcnt == 1 && current->softirqs_raised)
++		do_current_softirqs(1);
++	local_irq_enable();
++
++	if (--current->softirq_nestcnt == 0)
++		migrate_enable();
++}
++
++void local_bh_enable(void)
++{
++	__local_bh_enable();
++}
++EXPORT_SYMBOL(local_bh_enable);
++
++extern void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
++{
++	__local_bh_enable();
++	if (cnt & PREEMPT_CHECK_OFFSET)
++		preempt_enable();
++}
++
++void local_bh_enable_ip(unsigned long ip)
++{
++	local_bh_enable();
++}
++EXPORT_SYMBOL(local_bh_enable_ip);
++
++void _local_bh_enable(void)
++{
++	if (WARN_ON(current->softirq_nestcnt == 0))
++		return;
++	if (--current->softirq_nestcnt == 0)
++		migrate_enable();
++}
++EXPORT_SYMBOL(_local_bh_enable);
++
++int in_serving_softirq(void)
++{
++	return current->flags & PF_IN_SOFTIRQ;
++}
++EXPORT_SYMBOL(in_serving_softirq);
++
++/* Called with preemption disabled */
++static void run_ksoftirqd(unsigned int cpu)
++{
++	local_irq_disable();
++	current->softirq_nestcnt++;
++
++	do_current_softirqs(1);
++	current->softirq_nestcnt--;
++	rcu_note_context_switch(cpu);
++	local_irq_enable();
++}
++
++/*
++ * Called from netif_rx_ni(). Preemption enabled, but migration
++ * disabled. So the cpu can't go away under us.
++ */
++void thread_do_softirq(void)
++{
++	if (!in_serving_softirq() && current->softirqs_raised) {
++		current->softirq_nestcnt++;
++		do_current_softirqs(0);
++		current->softirq_nestcnt--;
++	}
++}
++
++static void do_raise_softirq_irqoff(unsigned int nr)
++{
++	trace_softirq_raise(nr);
++	or_softirq_pending(1UL << nr);
++
++	/*
++	 * If we are not in a hard interrupt and inside a bh disabled
++	 * region, we simply raise the flag on current. local_bh_enable()
++	 * will make sure that the softirq is executed. Otherwise we
++	 * delegate it to ksoftirqd.
++	 */
++	if (!in_irq() && current->softirq_nestcnt)
++		current->softirqs_raised |= (1U << nr);
++	else if (__this_cpu_read(ksoftirqd))
++		__this_cpu_read(ksoftirqd)->softirqs_raised |= (1U << nr);
++}
++
++void __raise_softirq_irqoff(unsigned int nr)
++{
++	do_raise_softirq_irqoff(nr);
++	if (!in_irq() && !current->softirq_nestcnt)
++		wakeup_softirqd();
++}
++
++/*
++ * This function must run with irqs disabled!
++ */
++void raise_softirq_irqoff(unsigned int nr)
++{
++	do_raise_softirq_irqoff(nr);
++
++	/*
++	 * If we're in an hard interrupt we let irq return code deal
++	 * with the wakeup of ksoftirqd.
++	 */
++	if (in_irq())
++		return;
++	/*
++	 * If we are in thread context but outside of a bh disabled
++	 * region, we need to wake ksoftirqd as well.
++	 *
++	 * CHECKME: Some of the places which do that could be wrapped
++	 * into local_bh_disable/enable pairs. Though it's unclear
++	 * whether this is worth the effort. To find those places just
++	 * raise a WARN() if the condition is met.
++	 */
++	if (!current->softirq_nestcnt)
++		wakeup_softirqd();
++}
++
++static inline int ksoftirqd_softirq_pending(void)
++{
++	return current->softirqs_raised;
++}
++
++static inline void local_bh_disable_nort(void) { }
++static inline void _local_bh_enable_nort(void) { }
++
++static inline void ksoftirqd_set_sched_params(unsigned int cpu)
++{
++	struct sched_param param = { .sched_priority = 1 };
++
++	sched_setscheduler(current, SCHED_FIFO, &param);
++	/* Take over all pending softirqs when starting */
++	local_irq_disable();
++	current->softirqs_raised = local_softirq_pending();
++	local_irq_enable();
++}
++
++static inline void ksoftirqd_clr_sched_params(unsigned int cpu, bool online)
++{
++	struct sched_param param = { .sched_priority = 0 };
++
++	sched_setscheduler(current, SCHED_NORMAL, &param);
++}
++
++#endif /* PREEMPT_RT_FULL */
++/*
+  * Enter an interrupt context.
+  */
+ void irq_enter(void)
+@@ -326,9 +732,9 @@
+ 		 * Prevent raise_softirq from needlessly waking up ksoftirqd
+ 		 * here, as softirq will be serviced on return from interrupt.
+ 		 */
+-		local_bh_disable();
++		local_bh_disable_nort();
+ 		tick_irq_enter();
+-		_local_bh_enable();
++		_local_bh_enable_nort();
+ 	}
+ 
+ 	__irq_enter();
+@@ -336,6 +742,7 @@
+ 
+ static inline void invoke_softirq(void)
+ {
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	if (!force_irqthreads) {
+ #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
+ 		/*
+@@ -355,6 +762,15 @@
+ 	} else {
+ 		wakeup_softirqd();
+ 	}
++#else /* PREEMPT_RT_FULL */
++	unsigned long flags;
++
++	local_irq_save(flags);
++	if (__this_cpu_read(ksoftirqd) &&
++			__this_cpu_read(ksoftirqd)->softirqs_raised)
++		wakeup_softirqd();
++	local_irq_restore(flags);
++#endif
+ }
+ 
+ static inline void tick_irq_exit(void)
+@@ -391,26 +807,6 @@
+ 	trace_hardirq_exit(); /* must be last! */
+ }
+ 
+-/*
+- * This function must run with irqs disabled!
+- */
+-inline void raise_softirq_irqoff(unsigned int nr)
+-{
+-	__raise_softirq_irqoff(nr);
+-
+-	/*
+-	 * If we're in an interrupt or softirq, we're done
+-	 * (this also catches softirq-disabled code). We will
+-	 * actually run the softirq once we return from
+-	 * the irq or softirq.
+-	 *
+-	 * Otherwise we wake up ksoftirqd to make sure we
+-	 * schedule the softirq soon.
+-	 */
+-	if (!in_interrupt())
+-		wakeup_softirqd();
+-}
+-
+ void raise_softirq(unsigned int nr)
+ {
+ 	unsigned long flags;
+@@ -420,12 +816,6 @@
+ 	local_irq_restore(flags);
+ }
+ 
+-void __raise_softirq_irqoff(unsigned int nr)
+-{
+-	trace_softirq_raise(nr);
+-	or_softirq_pending(1UL << nr);
+-}
+-
+ void open_softirq(int nr, void (*action)(struct softirq_action *))
+ {
+ 	softirq_vec[nr].action = action;
+@@ -442,15 +832,45 @@
+ static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec);
+ static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec);
+ 
++static void inline
++__tasklet_common_schedule(struct tasklet_struct *t, struct tasklet_head *head, unsigned int nr)
++{
++	if (tasklet_trylock(t)) {
++again:
++		/* We may have been preempted before tasklet_trylock
++		 * and __tasklet_action may have already run.
++		 * So double check the sched bit while the takslet
++		 * is locked before adding it to the list.
++		 */
++		if (test_bit(TASKLET_STATE_SCHED, &t->state)) {
++			t->next = NULL;
++			*head->tail = t;
++			head->tail = &(t->next);
++			raise_softirq_irqoff(nr);
++			tasklet_unlock(t);
++		} else {
++			/* This is subtle. If we hit the corner case above
++			 * It is possible that we get preempted right here,
++			 * and another task has successfully called
++			 * tasklet_schedule(), then this function, and
++			 * failed on the trylock. Thus we must be sure
++			 * before releasing the tasklet lock, that the
++			 * SCHED_BIT is clear. Otherwise the tasklet
++			 * may get its SCHED_BIT set, but not added to the
++			 * list
++			 */
++			if (!tasklet_tryunlock(t))
++				goto again;
++		}
++	}
++}
++
+ void __tasklet_schedule(struct tasklet_struct *t)
+ {
+ 	unsigned long flags;
+ 
+ 	local_irq_save(flags);
+-	t->next = NULL;
+-	*__this_cpu_read(tasklet_vec.tail) = t;
+-	__this_cpu_write(tasklet_vec.tail, &(t->next));
+-	raise_softirq_irqoff(TASKLET_SOFTIRQ);
++	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_vec), TASKLET_SOFTIRQ);
+ 	local_irq_restore(flags);
+ }
+ EXPORT_SYMBOL(__tasklet_schedule);
+@@ -460,10 +880,7 @@
+ 	unsigned long flags;
+ 
+ 	local_irq_save(flags);
+-	t->next = NULL;
+-	*__this_cpu_read(tasklet_hi_vec.tail) = t;
+-	__this_cpu_write(tasklet_hi_vec.tail,  &(t->next));
+-	raise_softirq_irqoff(HI_SOFTIRQ);
++	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_hi_vec), HI_SOFTIRQ);
+ 	local_irq_restore(flags);
+ }
+ EXPORT_SYMBOL(__tasklet_hi_schedule);
+@@ -472,48 +889,116 @@
+ {
+ 	BUG_ON(!irqs_disabled());
+ 
+-	t->next = __this_cpu_read(tasklet_hi_vec.head);
+-	__this_cpu_write(tasklet_hi_vec.head, t);
+-	__raise_softirq_irqoff(HI_SOFTIRQ);
++	__tasklet_hi_schedule(t);
+ }
+ EXPORT_SYMBOL(__tasklet_hi_schedule_first);
+ 
+-static void tasklet_action(struct softirq_action *a)
++void  tasklet_enable(struct tasklet_struct *t)
+ {
+-	struct tasklet_struct *list;
++	if (!atomic_dec_and_test(&t->count))
++		return;
++	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
++		tasklet_schedule(t);
++}
++EXPORT_SYMBOL(tasklet_enable);
+ 
+-	local_irq_disable();
+-	list = __this_cpu_read(tasklet_vec.head);
+-	__this_cpu_write(tasklet_vec.head, NULL);
+-	__this_cpu_write(tasklet_vec.tail, this_cpu_ptr(&tasklet_vec.head));
+-	local_irq_enable();
++void  tasklet_hi_enable(struct tasklet_struct *t)
++{
++	if (!atomic_dec_and_test(&t->count))
++		return;
++	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
++		tasklet_hi_schedule(t);
++}
++EXPORT_SYMBOL(tasklet_hi_enable);
++
++static void __tasklet_action(struct softirq_action *a,
++			     struct tasklet_struct *list)
++{
++	int loops = 1000000;
+ 
+ 	while (list) {
+ 		struct tasklet_struct *t = list;
+ 
+ 		list = list->next;
+ 
+-		if (tasklet_trylock(t)) {
+-			if (!atomic_read(&t->count)) {
+-				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
+-							&t->state))
+-					BUG();
+-				t->func(t->data);
+-				tasklet_unlock(t);
+-				continue;
+-			}
+-			tasklet_unlock(t);
++		/*
++		 * Should always succeed - after a tasklist got on the
++		 * list (after getting the SCHED bit set from 0 to 1),
++		 * nothing but the tasklet softirq it got queued to can
++		 * lock it:
++		 */
++		if (!tasklet_trylock(t)) {
++			WARN_ON(1);
++			continue;
+ 		}
+ 
+-		local_irq_disable();
+ 		t->next = NULL;
+-		*__this_cpu_read(tasklet_vec.tail) = t;
+-		__this_cpu_write(tasklet_vec.tail, &(t->next));
+-		__raise_softirq_irqoff(TASKLET_SOFTIRQ);
+-		local_irq_enable();
++
++		/*
++		 * If we cannot handle the tasklet because it's disabled,
++		 * mark it as pending. tasklet_enable() will later
++		 * re-schedule the tasklet.
++		 */
++		if (unlikely(atomic_read(&t->count))) {
++out_disabled:
++			/* implicit unlock: */
++			wmb();
++			t->state = TASKLET_STATEF_PENDING;
++			continue;
++		}
++
++		/*
++		 * After this point on the tasklet might be rescheduled
++		 * on another CPU, but it can only be added to another
++		 * CPU's tasklet list if we unlock the tasklet (which we
++		 * dont do yet).
++		 */
++		if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
++			WARN_ON(1);
++
++again:
++		t->func(t->data);
++
++		/*
++		 * Try to unlock the tasklet. We must use cmpxchg, because
++		 * another CPU might have scheduled or disabled the tasklet.
++		 * We only allow the STATE_RUN -> 0 transition here.
++		 */
++		while (!tasklet_tryunlock(t)) {
++			/*
++			 * If it got disabled meanwhile, bail out:
++			 */
++			if (atomic_read(&t->count))
++				goto out_disabled;
++			/*
++			 * If it got scheduled meanwhile, re-execute
++			 * the tasklet function:
++			 */
++			if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
++				goto again;
++			if (!--loops) {
++				printk("hm, tasklet state: %08lx\n", t->state);
++				WARN_ON(1);
++				tasklet_unlock(t);
++				break;
++			}
++		}
+ 	}
+ }
+ 
++static void tasklet_action(struct softirq_action *a)
++{
++	struct tasklet_struct *list;
++
++	local_irq_disable();
++	list = __get_cpu_var(tasklet_vec).head;
++	__get_cpu_var(tasklet_vec).head = NULL;
++	__get_cpu_var(tasklet_vec).tail = &__get_cpu_var(tasklet_vec).head;
++	local_irq_enable();
++
++	__tasklet_action(a, list);
++}
++
+ static void tasklet_hi_action(struct softirq_action *a)
+ {
+ 	struct tasklet_struct *list;
+@@ -524,30 +1009,7 @@
+ 	__this_cpu_write(tasklet_hi_vec.tail, this_cpu_ptr(&tasklet_hi_vec.head));
+ 	local_irq_enable();
+ 
+-	while (list) {
+-		struct tasklet_struct *t = list;
+-
+-		list = list->next;
+-
+-		if (tasklet_trylock(t)) {
+-			if (!atomic_read(&t->count)) {
+-				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
+-							&t->state))
+-					BUG();
+-				t->func(t->data);
+-				tasklet_unlock(t);
+-				continue;
+-			}
+-			tasklet_unlock(t);
+-		}
+-
+-		local_irq_disable();
+-		t->next = NULL;
+-		*__this_cpu_read(tasklet_hi_vec.tail) = t;
+-		__this_cpu_write(tasklet_hi_vec.tail, &(t->next));
+-		__raise_softirq_irqoff(HI_SOFTIRQ);
+-		local_irq_enable();
+-	}
++	__tasklet_action(a, list);
+ }
+ 
+ void tasklet_init(struct tasklet_struct *t,
+@@ -568,7 +1030,7 @@
+ 
+ 	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
+ 		do {
+-			yield();
++			msleep(1);
+ 		} while (test_bit(TASKLET_STATE_SCHED, &t->state));
+ 	}
+ 	tasklet_unlock_wait(t);
+@@ -642,26 +1104,26 @@
+ 	open_softirq(HI_SOFTIRQ, tasklet_hi_action);
+ }
+ 
+-static int ksoftirqd_should_run(unsigned int cpu)
+-{
+-	return local_softirq_pending();
+-}
+-
+-static void run_ksoftirqd(unsigned int cpu)
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
++void tasklet_unlock_wait(struct tasklet_struct *t)
+ {
+-	local_irq_disable();
+-	if (local_softirq_pending()) {
++	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
+ 		/*
+-		 * We can safely run softirq on inline stack, as we are not deep
+-		 * in the task stack here.
++		 * Hack for now to avoid this busy-loop:
+ 		 */
+-		__do_softirq();
+-		rcu_note_context_switch(cpu);
+-		local_irq_enable();
+-		cond_resched();
+-		return;
++#ifdef CONFIG_PREEMPT_RT_FULL
++		msleep(1);
++#else
++		barrier();
++#endif
+ 	}
+-	local_irq_enable();
++}
++EXPORT_SYMBOL(tasklet_unlock_wait);
++#endif
++
++static int ksoftirqd_should_run(unsigned int cpu)
++{
++	return ksoftirqd_softirq_pending();
+ }
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+@@ -743,6 +1205,8 @@
+ 
+ static struct smp_hotplug_thread softirq_threads = {
+ 	.store			= &ksoftirqd,
++	.setup			= ksoftirqd_set_sched_params,
++	.cleanup		= ksoftirqd_clr_sched_params,
+ 	.thread_should_run	= ksoftirqd_should_run,
+ 	.thread_fn		= run_ksoftirqd,
+ 	.thread_comm		= "ksoftirqd/%u",
+diff -Nur linux-3.18.8.orig/kernel/stop_machine.c linux-3.18.8/kernel/stop_machine.c
+--- linux-3.18.8.orig/kernel/stop_machine.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/stop_machine.c	2015-03-03 08:05:18.000000000 +0100
+@@ -30,12 +30,12 @@
+ 	atomic_t		nr_todo;	/* nr left to execute */
+ 	bool			executed;	/* actually executed? */
+ 	int			ret;		/* collected return value */
+-	struct completion	completion;	/* fired if nr_todo reaches 0 */
++	struct task_struct	*waiter;	/* woken when nr_todo reaches 0 */
+ };
+ 
+ /* the actual stopper, one per every possible cpu, enabled on online cpus */
+ struct cpu_stopper {
+-	spinlock_t		lock;
++	raw_spinlock_t		lock;
+ 	bool			enabled;	/* is this stopper enabled? */
+ 	struct list_head	works;		/* list of pending works */
+ };
+@@ -56,7 +56,7 @@
+ {
+ 	memset(done, 0, sizeof(*done));
+ 	atomic_set(&done->nr_todo, nr_todo);
+-	init_completion(&done->completion);
++	done->waiter = current;
+ }
+ 
+ /* signal completion unless @done is NULL */
+@@ -65,8 +65,10 @@
+ 	if (done) {
+ 		if (executed)
+ 			done->executed = true;
+-		if (atomic_dec_and_test(&done->nr_todo))
+-			complete(&done->completion);
++		if (atomic_dec_and_test(&done->nr_todo)) {
++			wake_up_process(done->waiter);
++			done->waiter = NULL;
++		}
+ 	}
+ }
+ 
+@@ -78,7 +80,7 @@
+ 
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&stopper->lock, flags);
++	raw_spin_lock_irqsave(&stopper->lock, flags);
+ 
+ 	if (stopper->enabled) {
+ 		list_add_tail(&work->list, &stopper->works);
+@@ -86,7 +88,23 @@
+ 	} else
+ 		cpu_stop_signal_done(work->done, false);
+ 
+-	spin_unlock_irqrestore(&stopper->lock, flags);
++	raw_spin_unlock_irqrestore(&stopper->lock, flags);
++}
++
++static void wait_for_stop_done(struct cpu_stop_done *done)
++{
++	set_current_state(TASK_UNINTERRUPTIBLE);
++	while (atomic_read(&done->nr_todo)) {
++		schedule();
++		set_current_state(TASK_UNINTERRUPTIBLE);
++	}
++	/*
++	 * We need to wait until cpu_stop_signal_done() has cleared
++	 * done->waiter.
++	 */
++	while (done->waiter)
++		cpu_relax();
++	set_current_state(TASK_RUNNING);
+ }
+ 
+ /**
+@@ -120,7 +138,7 @@
+ 
+ 	cpu_stop_init_done(&done, 1);
+ 	cpu_stop_queue_work(cpu, &work);
+-	wait_for_completion(&done.completion);
++	wait_for_stop_done(&done);
+ 	return done.executed ? done.ret : -ENOENT;
+ }
+ 
+@@ -248,7 +266,7 @@
+ 	struct irq_cpu_stop_queue_work_info call_args;
+ 	struct multi_stop_data msdata;
+ 
+-	preempt_disable();
++	preempt_disable_nort();
+ 	msdata = (struct multi_stop_data){
+ 		.fn = fn,
+ 		.data = arg,
+@@ -281,7 +299,7 @@
+ 	 * This relies on the stopper workqueues to be FIFO.
+ 	 */
+ 	if (!cpu_active(cpu1) || !cpu_active(cpu2)) {
+-		preempt_enable();
++		preempt_enable_nort();
+ 		return -ENOENT;
+ 	}
+ 
+@@ -295,9 +313,9 @@
+ 				 &irq_cpu_stop_queue_work,
+ 				 &call_args, 1);
+ 	lg_local_unlock(&stop_cpus_lock);
+-	preempt_enable();
++	preempt_enable_nort();
+ 
+-	wait_for_completion(&done.completion);
++	wait_for_stop_done(&done);
+ 
+ 	return done.executed ? done.ret : -ENOENT;
+ }
+@@ -329,7 +347,7 @@
+ 
+ static void queue_stop_cpus_work(const struct cpumask *cpumask,
+ 				 cpu_stop_fn_t fn, void *arg,
+-				 struct cpu_stop_done *done)
++				 struct cpu_stop_done *done, bool inactive)
+ {
+ 	struct cpu_stop_work *work;
+ 	unsigned int cpu;
+@@ -343,11 +361,13 @@
+ 	}
+ 
+ 	/*
+-	 * Disable preemption while queueing to avoid getting
+-	 * preempted by a stopper which might wait for other stoppers
+-	 * to enter @fn which can lead to deadlock.
++	 * Make sure that all work is queued on all cpus before
++	 * any of the cpus can execute it.
+ 	 */
+-	lg_global_lock(&stop_cpus_lock);
++	if (!inactive)
++		lg_global_lock(&stop_cpus_lock);
++	else
++		lg_global_trylock_relax(&stop_cpus_lock);
+ 	for_each_cpu(cpu, cpumask)
+ 		cpu_stop_queue_work(cpu, &per_cpu(stop_cpus_work, cpu));
+ 	lg_global_unlock(&stop_cpus_lock);
+@@ -359,8 +379,8 @@
+ 	struct cpu_stop_done done;
+ 
+ 	cpu_stop_init_done(&done, cpumask_weight(cpumask));
+-	queue_stop_cpus_work(cpumask, fn, arg, &done);
+-	wait_for_completion(&done.completion);
++	queue_stop_cpus_work(cpumask, fn, arg, &done, false);
++	wait_for_stop_done(&done);
+ 	return done.executed ? done.ret : -ENOENT;
+ }
+ 
+@@ -439,9 +459,9 @@
+ 	unsigned long flags;
+ 	int run;
+ 
+-	spin_lock_irqsave(&stopper->lock, flags);
++	raw_spin_lock_irqsave(&stopper->lock, flags);
+ 	run = !list_empty(&stopper->works);
+-	spin_unlock_irqrestore(&stopper->lock, flags);
++	raw_spin_unlock_irqrestore(&stopper->lock, flags);
+ 	return run;
+ }
+ 
+@@ -453,13 +473,13 @@
+ 
+ repeat:
+ 	work = NULL;
+-	spin_lock_irq(&stopper->lock);
++	raw_spin_lock_irq(&stopper->lock);
+ 	if (!list_empty(&stopper->works)) {
+ 		work = list_first_entry(&stopper->works,
+ 					struct cpu_stop_work, list);
+ 		list_del_init(&work->list);
+ 	}
+-	spin_unlock_irq(&stopper->lock);
++	raw_spin_unlock_irq(&stopper->lock);
+ 
+ 	if (work) {
+ 		cpu_stop_fn_t fn = work->fn;
+@@ -467,6 +487,16 @@
+ 		struct cpu_stop_done *done = work->done;
+ 		char ksym_buf[KSYM_NAME_LEN] __maybe_unused;
+ 
++		/*
++		 * Wait until the stopper finished scheduling on all
++		 * cpus
++		 */
++		lg_global_lock(&stop_cpus_lock);
++		/*
++		 * Let other cpu threads continue as well
++		 */
++		lg_global_unlock(&stop_cpus_lock);
++
+ 		/* cpu stop callbacks are not allowed to sleep */
+ 		preempt_disable();
+ 
+@@ -481,7 +511,13 @@
+ 			  kallsyms_lookup((unsigned long)fn, NULL, NULL, NULL,
+ 					  ksym_buf), arg);
+ 
++		/*
++		 * Make sure that the wakeup and setting done->waiter
++		 * to NULL is atomic.
++		 */
++		local_irq_disable();
+ 		cpu_stop_signal_done(done, true);
++		local_irq_enable();
+ 		goto repeat;
+ 	}
+ }
+@@ -500,20 +536,20 @@
+ 	unsigned long flags;
+ 
+ 	/* drain remaining works */
+-	spin_lock_irqsave(&stopper->lock, flags);
++	raw_spin_lock_irqsave(&stopper->lock, flags);
+ 	list_for_each_entry(work, &stopper->works, list)
+ 		cpu_stop_signal_done(work->done, false);
+ 	stopper->enabled = false;
+-	spin_unlock_irqrestore(&stopper->lock, flags);
++	raw_spin_unlock_irqrestore(&stopper->lock, flags);
+ }
+ 
+ static void cpu_stop_unpark(unsigned int cpu)
+ {
+ 	struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+ 
+-	spin_lock_irq(&stopper->lock);
++	raw_spin_lock_irq(&stopper->lock);
+ 	stopper->enabled = true;
+-	spin_unlock_irq(&stopper->lock);
++	raw_spin_unlock_irq(&stopper->lock);
+ }
+ 
+ static struct smp_hotplug_thread cpu_stop_threads = {
+@@ -535,10 +571,12 @@
+ 	for_each_possible_cpu(cpu) {
+ 		struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+ 
+-		spin_lock_init(&stopper->lock);
++		raw_spin_lock_init(&stopper->lock);
+ 		INIT_LIST_HEAD(&stopper->works);
+ 	}
+ 
++	lg_lock_init(&stop_cpus_lock, "stop_cpus_lock");
++
+ 	BUG_ON(smpboot_register_percpu_thread(&cpu_stop_threads));
+ 	stop_machine_initialized = true;
+ 	return 0;
+@@ -634,11 +672,11 @@
+ 	set_state(&msdata, MULTI_STOP_PREPARE);
+ 	cpu_stop_init_done(&done, num_active_cpus());
+ 	queue_stop_cpus_work(cpu_active_mask, multi_cpu_stop, &msdata,
+-			     &done);
++			     &done, true);
+ 	ret = multi_cpu_stop(&msdata);
+ 
+ 	/* Busy wait for completion. */
+-	while (!completion_done(&done.completion))
++	while (atomic_read(&done.nr_todo))
+ 		cpu_relax();
+ 
+ 	mutex_unlock(&stop_cpus_mutex);
+diff -Nur linux-3.18.8.orig/kernel/time/hrtimer.c linux-3.18.8/kernel/time/hrtimer.c
+--- linux-3.18.8.orig/kernel/time/hrtimer.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/hrtimer.c	2015-03-03 08:05:18.000000000 +0100
+@@ -48,11 +48,13 @@
+ #include <linux/sched/rt.h>
+ #include <linux/sched/deadline.h>
+ #include <linux/timer.h>
++#include <linux/kthread.h>
+ #include <linux/freezer.h>
+ 
+ #include <asm/uaccess.h>
+ 
+ #include <trace/events/timer.h>
++#include <trace/events/hist.h>
+ 
+ #include "timekeeping.h"
+ 
+@@ -568,8 +570,7 @@
+ 	 * When the callback is running, we do not reprogram the clock event
+ 	 * device. The timer callback is either running on a different CPU or
+ 	 * the callback is executed in the hrtimer_interrupt context. The
+-	 * reprogramming is handled either by the softirq, which called the
+-	 * callback or at the end of the hrtimer_interrupt.
++	 * reprogramming is handled at the end of the hrtimer_interrupt.
+ 	 */
+ 	if (hrtimer_callback_running(timer))
+ 		return 0;
+@@ -604,6 +605,9 @@
+ 	return res;
+ }
+ 
++static void __run_hrtimer(struct hrtimer *timer, ktime_t *now);
++static int hrtimer_rt_defer(struct hrtimer *timer);
++
+ /*
+  * Initialize the high resolution related parts of cpu_base
+  */
+@@ -613,6 +617,21 @@
+ 	base->hres_active = 0;
+ }
+ 
++static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
++					    struct hrtimer_clock_base *base,
++					    int wakeup)
++{
++	if (!hrtimer_reprogram(timer, base))
++		return 0;
++	if (!wakeup)
++		return -ETIME;
++#ifdef CONFIG_PREEMPT_RT_BASE
++	if (!hrtimer_rt_defer(timer))
++		return -ETIME;
++#endif
++	return 1;
++}
++
+ static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
+ {
+ 	ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
+@@ -678,6 +697,44 @@
+ 
+ static DECLARE_WORK(hrtimer_work, clock_was_set_work);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * RT can not call schedule_work from real interrupt context.
++ * Need to make a thread to do the real work.
++ */
++static struct task_struct *clock_set_delay_thread;
++static bool do_clock_set_delay;
++
++static int run_clock_set_delay(void *ignore)
++{
++	while (!kthread_should_stop()) {
++		set_current_state(TASK_INTERRUPTIBLE);
++		if (do_clock_set_delay) {
++			do_clock_set_delay = false;
++			schedule_work(&hrtimer_work);
++		}
++		schedule();
++	}
++	__set_current_state(TASK_RUNNING);
++	return 0;
++}
++
++void clock_was_set_delayed(void)
++{
++	do_clock_set_delay = true;
++	/* Make visible before waking up process */
++	smp_wmb();
++	wake_up_process(clock_set_delay_thread);
++}
++
++static __init int create_clock_set_delay_thread(void)
++{
++	clock_set_delay_thread = kthread_run(run_clock_set_delay, NULL, "kclksetdelayd");
++	BUG_ON(!clock_set_delay_thread);
++	return 0;
++}
++early_initcall(create_clock_set_delay_thread);
++#else /* PREEMPT_RT_FULL */
+ /*
+  * Called from timekeeping and resume code to reprogramm the hrtimer
+  * interrupt device on all cpus.
+@@ -686,6 +743,7 @@
+ {
+ 	schedule_work(&hrtimer_work);
+ }
++#endif
+ 
+ #else
+ 
+@@ -694,6 +752,13 @@
+ static inline int hrtimer_switch_to_hres(void) { return 0; }
+ static inline void
+ hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
++static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
++					    struct hrtimer_clock_base *base,
++					    int wakeup)
++{
++	return 0;
++}
++
+ static inline int hrtimer_reprogram(struct hrtimer *timer,
+ 				    struct hrtimer_clock_base *base)
+ {
+@@ -701,7 +766,6 @@
+ }
+ static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
+ static inline void retrigger_next_event(void *arg) { }
+-
+ #endif /* CONFIG_HIGH_RES_TIMERS */
+ 
+ /*
+@@ -819,6 +883,32 @@
+ }
+ EXPORT_SYMBOL_GPL(hrtimer_forward);
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++# define wake_up_timer_waiters(b)	wake_up(&(b)->wait)
++
++/**
++ * hrtimer_wait_for_timer - Wait for a running timer
++ *
++ * @timer:	timer to wait for
++ *
++ * The function waits in case the timers callback function is
++ * currently executed on the waitqueue of the timer base. The
++ * waitqueue is woken up after the timer callback function has
++ * finished execution.
++ */
++void hrtimer_wait_for_timer(const struct hrtimer *timer)
++{
++	struct hrtimer_clock_base *base = timer->base;
++
++	if (base && base->cpu_base && !timer->irqsafe)
++		wait_event(base->cpu_base->wait,
++			   !(timer->state & HRTIMER_STATE_CALLBACK));
++}
++
++#else
++# define wake_up_timer_waiters(b)	do { } while (0)
++#endif
++
+ /*
+  * enqueue_hrtimer - internal function to (re)start a timer
+  *
+@@ -862,6 +952,11 @@
+ 	if (!(timer->state & HRTIMER_STATE_ENQUEUED))
+ 		goto out;
+ 
++	if (unlikely(!list_empty(&timer->cb_entry))) {
++		list_del_init(&timer->cb_entry);
++		goto out;
++	}
++
+ 	next_timer = timerqueue_getnext(&base->active);
+ 	timerqueue_del(&base->active, &timer->node);
+ 	if (&timer->node == next_timer) {
+@@ -949,7 +1044,16 @@
+ 	new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
+ 
+ 	timer_stats_hrtimer_set_start_info(timer);
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++	{
++		ktime_t now = new_base->get_time();
+ 
++		if (ktime_to_ns(tim) < ktime_to_ns(now))
++			timer->praecox = now;
++		else
++			timer->praecox = ktime_set(0, 0);
++	}
++#endif
+ 	leftmost = enqueue_hrtimer(timer, new_base);
+ 
+ 	if (!leftmost) {
+@@ -963,15 +1067,26 @@
+ 		 * on dynticks target.
+ 		 */
+ 		wake_up_nohz_cpu(new_base->cpu_base->cpu);
+-	} else if (new_base->cpu_base == this_cpu_ptr(&hrtimer_bases) &&
+-			hrtimer_reprogram(timer, new_base)) {
++	} else if (new_base->cpu_base == this_cpu_ptr(&hrtimer_bases)) {
++
++		ret = hrtimer_enqueue_reprogram(timer, new_base, wakeup);
++		if (ret < 0) {
++			/*
++			 * In case we failed to reprogram the timer (mostly
++			 * because out current timer is already elapsed),
++			 * remove it again and report a failure. This avoids
++			 * stale base->first entries.
++			 */
++			debug_deactivate(timer);
++			__remove_hrtimer(timer, new_base,
++				timer->state & HRTIMER_STATE_CALLBACK, 0);
++		} else if (ret > 0) {
+ 		/*
+ 		 * Only allow reprogramming if the new base is on this CPU.
+ 		 * (it might still be on another CPU if the timer was pending)
+ 		 *
+ 		 * XXX send_remote_softirq() ?
+ 		 */
+-		if (wakeup) {
+ 			/*
+ 			 * We need to drop cpu_base->lock to avoid a
+ 			 * lock ordering issue vs. rq->lock.
+@@ -979,9 +1094,7 @@
+ 			raw_spin_unlock(&new_base->cpu_base->lock);
+ 			raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ 			local_irq_restore(flags);
+-			return ret;
+-		} else {
+-			__raise_softirq_irqoff(HRTIMER_SOFTIRQ);
++			return 0;
+ 		}
+ 	}
+ 
+@@ -1072,7 +1185,7 @@
+ 
+ 		if (ret >= 0)
+ 			return ret;
+-		cpu_relax();
++		hrtimer_wait_for_timer(timer);
+ 	}
+ }
+ EXPORT_SYMBOL_GPL(hrtimer_cancel);
+@@ -1151,6 +1264,7 @@
+ 
+ 	base = hrtimer_clockid_to_base(clock_id);
+ 	timer->base = &cpu_base->clock_base[base];
++	INIT_LIST_HEAD(&timer->cb_entry);
+ 	timerqueue_init(&timer->node);
+ 
+ #ifdef CONFIG_TIMER_STATS
+@@ -1234,6 +1348,126 @@
+ 	timer->state &= ~HRTIMER_STATE_CALLBACK;
+ }
+ 
++static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer);
++
++#ifdef CONFIG_PREEMPT_RT_BASE
++static void hrtimer_rt_reprogram(int restart, struct hrtimer *timer,
++				 struct hrtimer_clock_base *base)
++{
++	/*
++	 * Note, we clear the callback flag before we requeue the
++	 * timer otherwise we trigger the callback_running() check
++	 * in hrtimer_reprogram().
++	 */
++	timer->state &= ~HRTIMER_STATE_CALLBACK;
++
++	if (restart != HRTIMER_NORESTART) {
++		BUG_ON(hrtimer_active(timer));
++		/*
++		 * Enqueue the timer, if it's the leftmost timer then
++		 * we need to reprogram it.
++		 */
++		if (!enqueue_hrtimer(timer, base))
++			return;
++
++#ifndef CONFIG_HIGH_RES_TIMERS
++	}
++#else
++		if (base->cpu_base->hres_active &&
++		    hrtimer_reprogram(timer, base))
++			goto requeue;
++
++	} else if (hrtimer_active(timer)) {
++		/*
++		 * If the timer was rearmed on another CPU, reprogram
++		 * the event device.
++		 */
++		if (&timer->node == base->active.next &&
++		    base->cpu_base->hres_active &&
++		    hrtimer_reprogram(timer, base))
++			goto requeue;
++	}
++	return;
++
++requeue:
++	/*
++	 * Timer is expired. Thus move it from tree to pending list
++	 * again.
++	 */
++	__remove_hrtimer(timer, base, timer->state, 0);
++	list_add_tail(&timer->cb_entry, &base->expired);
++#endif
++}
++
++/*
++ * The changes in mainline which removed the callback modes from
++ * hrtimer are not yet working with -rt. The non wakeup_process()
++ * based callbacks which involve sleeping locks need to be treated
++ * seperately.
++ */
++static void hrtimer_rt_run_pending(void)
++{
++	enum hrtimer_restart (*fn)(struct hrtimer *);
++	struct hrtimer_cpu_base *cpu_base;
++	struct hrtimer_clock_base *base;
++	struct hrtimer *timer;
++	int index, restart;
++
++	local_irq_disable();
++	cpu_base = &per_cpu(hrtimer_bases, smp_processor_id());
++
++	raw_spin_lock(&cpu_base->lock);
++
++	for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
++		base = &cpu_base->clock_base[index];
++
++		while (!list_empty(&base->expired)) {
++			timer = list_first_entry(&base->expired,
++						 struct hrtimer, cb_entry);
++
++			/*
++			 * Same as the above __run_hrtimer function
++			 * just we run with interrupts enabled.
++			 */
++			debug_hrtimer_deactivate(timer);
++			__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
++			timer_stats_account_hrtimer(timer);
++			fn = timer->function;
++
++			raw_spin_unlock_irq(&cpu_base->lock);
++			restart = fn(timer);
++			raw_spin_lock_irq(&cpu_base->lock);
++
++			hrtimer_rt_reprogram(restart, timer, base);
++		}
++	}
++
++	raw_spin_unlock_irq(&cpu_base->lock);
++
++	wake_up_timer_waiters(cpu_base);
++}
++
++static int hrtimer_rt_defer(struct hrtimer *timer)
++{
++	if (timer->irqsafe)
++		return 0;
++
++	__remove_hrtimer(timer, timer->base, timer->state, 0);
++	list_add_tail(&timer->cb_entry, &timer->base->expired);
++	return 1;
++}
++
++#else
++
++static inline void hrtimer_rt_run_pending(void)
++{
++	hrtimer_peek_ahead_timers();
++}
++
++static inline int hrtimer_rt_defer(struct hrtimer *timer) { return 0; }
++
++#endif
++
+ #ifdef CONFIG_HIGH_RES_TIMERS
+ 
+ /*
+@@ -1244,7 +1478,7 @@
+ {
+ 	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+ 	ktime_t expires_next, now, entry_time, delta;
+-	int i, retries = 0;
++	int i, retries = 0, raise = 0;
+ 
+ 	BUG_ON(!cpu_base->hres_active);
+ 	cpu_base->nr_events++;
+@@ -1279,6 +1513,15 @@
+ 
+ 			timer = container_of(node, struct hrtimer, node);
+ 
++			trace_hrtimer_interrupt(raw_smp_processor_id(),
++			    ktime_to_ns(ktime_sub(ktime_to_ns(timer->praecox) ?
++				timer->praecox : hrtimer_get_expires(timer),
++				basenow)),
++			    current,
++			    timer->function == hrtimer_wakeup ?
++			    container_of(timer, struct hrtimer_sleeper,
++				timer)->task : NULL);
++
+ 			/*
+ 			 * The immediate goal for using the softexpires is
+ 			 * minimizing wakeups, not running timers at the
+@@ -1304,7 +1547,10 @@
+ 				break;
+ 			}
+ 
+-			__run_hrtimer(timer, &basenow);
++			if (!hrtimer_rt_defer(timer))
++				__run_hrtimer(timer, &basenow);
++			else
++				raise = 1;
+ 		}
+ 	}
+ 
+@@ -1319,7 +1565,7 @@
+ 	if (expires_next.tv64 == KTIME_MAX ||
+ 	    !tick_program_event(expires_next, 0)) {
+ 		cpu_base->hang_detected = 0;
+-		return;
++		goto out;
+ 	}
+ 
+ 	/*
+@@ -1363,6 +1609,9 @@
+ 	tick_program_event(expires_next, 1);
+ 	printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
+ 		    ktime_to_ns(delta));
++out:
++	if (raise)
++		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ }
+ 
+ /*
+@@ -1398,18 +1647,18 @@
+ 	__hrtimer_peek_ahead_timers();
+ 	local_irq_restore(flags);
+ }
+-
+-static void run_hrtimer_softirq(struct softirq_action *h)
+-{
+-	hrtimer_peek_ahead_timers();
+-}
+-
+ #else /* CONFIG_HIGH_RES_TIMERS */
+ 
+ static inline void __hrtimer_peek_ahead_timers(void) { }
+ 
+ #endif	/* !CONFIG_HIGH_RES_TIMERS */
+ 
++
++static void run_hrtimer_softirq(struct softirq_action *h)
++{
++	hrtimer_rt_run_pending();
++}
++
+ /*
+  * Called from timer softirq every jiffy, expire hrtimers:
+  *
+@@ -1442,7 +1691,7 @@
+ 	struct timerqueue_node *node;
+ 	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
+ 	struct hrtimer_clock_base *base;
+-	int index, gettime = 1;
++	int index, gettime = 1, raise = 0;
+ 
+ 	if (hrtimer_hres_active())
+ 		return;
+@@ -1467,10 +1716,16 @@
+ 					hrtimer_get_expires_tv64(timer))
+ 				break;
+ 
+-			__run_hrtimer(timer, &base->softirq_time);
++			if (!hrtimer_rt_defer(timer))
++				__run_hrtimer(timer, &base->softirq_time);
++			else
++				raise = 1;
+ 		}
+ 		raw_spin_unlock(&cpu_base->lock);
+ 	}
++
++	if (raise)
++		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ }
+ 
+ /*
+@@ -1492,16 +1747,18 @@
+ void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
+ {
+ 	sl->timer.function = hrtimer_wakeup;
++	sl->timer.irqsafe = 1;
+ 	sl->task = task;
+ }
+ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
+ 
+-static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
++static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode,
++				unsigned long state)
+ {
+ 	hrtimer_init_sleeper(t, current);
+ 
+ 	do {
+-		set_current_state(TASK_INTERRUPTIBLE);
++		set_current_state(state);
+ 		hrtimer_start_expires(&t->timer, mode);
+ 		if (!hrtimer_active(&t->timer))
+ 			t->task = NULL;
+@@ -1545,7 +1802,8 @@
+ 				HRTIMER_MODE_ABS);
+ 	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
+ 
+-	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
++	/* cpu_chill() does not care about restart state. */
++	if (do_nanosleep(&t, HRTIMER_MODE_ABS, TASK_INTERRUPTIBLE))
+ 		goto out;
+ 
+ 	rmtp = restart->nanosleep.rmtp;
+@@ -1562,8 +1820,10 @@
+ 	return ret;
+ }
+ 
+-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
+-		       const enum hrtimer_mode mode, const clockid_t clockid)
++static long
++__hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
++		    const enum hrtimer_mode mode, const clockid_t clockid,
++		    unsigned long state)
+ {
+ 	struct restart_block *restart;
+ 	struct hrtimer_sleeper t;
+@@ -1576,7 +1836,7 @@
+ 
+ 	hrtimer_init_on_stack(&t.timer, clockid, mode);
+ 	hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
+-	if (do_nanosleep(&t, mode))
++	if (do_nanosleep(&t, mode, state))
+ 		goto out;
+ 
+ 	/* Absolute timers do not update the rmtp value and restart: */
+@@ -1603,6 +1863,12 @@
+ 	return ret;
+ }
+ 
++long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
++		       const enum hrtimer_mode mode, const clockid_t clockid)
++{
++	return __hrtimer_nanosleep(rqtp, rmtp, mode, clockid, TASK_INTERRUPTIBLE);
++}
++
+ SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
+ 		struct timespec __user *, rmtp)
+ {
+@@ -1617,6 +1883,26 @@
+ 	return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * Sleep for 1 ms in hope whoever holds what we want will let it go.
++ */
++void cpu_chill(void)
++{
++	struct timespec tu = {
++		.tv_nsec = NSEC_PER_MSEC,
++	};
++	unsigned int freeze_flag = current->flags & PF_NOFREEZE;
++
++	current->flags |= PF_NOFREEZE;
++	__hrtimer_nanosleep(&tu, NULL, HRTIMER_MODE_REL, CLOCK_MONOTONIC,
++			    TASK_UNINTERRUPTIBLE);
++	if (!freeze_flag)
++		current->flags &= ~PF_NOFREEZE;
++}
++EXPORT_SYMBOL(cpu_chill);
++#endif
++
+ /*
+  * Functions related to boot-time initialization:
+  */
+@@ -1628,10 +1914,14 @@
+ 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+ 		cpu_base->clock_base[i].cpu_base = cpu_base;
+ 		timerqueue_init_head(&cpu_base->clock_base[i].active);
++		INIT_LIST_HEAD(&cpu_base->clock_base[i].expired);
+ 	}
+ 
+ 	cpu_base->cpu = cpu;
+ 	hrtimer_init_hres(cpu_base);
++#ifdef CONFIG_PREEMPT_RT_BASE
++	init_waitqueue_head(&cpu_base->wait);
++#endif
+ }
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+@@ -1744,9 +2034,7 @@
+ 	hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
+ 			  (void *)(long)smp_processor_id());
+ 	register_cpu_notifier(&hrtimers_nb);
+-#ifdef CONFIG_HIGH_RES_TIMERS
+ 	open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
+-#endif
+ }
+ 
+ /**
+diff -Nur linux-3.18.8.orig/kernel/time/itimer.c linux-3.18.8/kernel/time/itimer.c
+--- linux-3.18.8.orig/kernel/time/itimer.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/itimer.c	2015-03-03 08:05:18.000000000 +0100
+@@ -213,6 +213,7 @@
+ 		/* We are sharing ->siglock with it_real_fn() */
+ 		if (hrtimer_try_to_cancel(timer) < 0) {
+ 			spin_unlock_irq(&tsk->sighand->siglock);
++			hrtimer_wait_for_timer(&tsk->signal->real_timer);
+ 			goto again;
+ 		}
+ 		expires = timeval_to_ktime(value->it_value);
+diff -Nur linux-3.18.8.orig/kernel/time/jiffies.c linux-3.18.8/kernel/time/jiffies.c
+--- linux-3.18.8.orig/kernel/time/jiffies.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/jiffies.c	2015-03-03 08:05:18.000000000 +0100
+@@ -73,7 +73,8 @@
+ 	.shift		= JIFFIES_SHIFT,
+ };
+ 
+-__cacheline_aligned_in_smp DEFINE_SEQLOCK(jiffies_lock);
++__cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(jiffies_lock);
++__cacheline_aligned_in_smp seqcount_t jiffies_seq;
+ 
+ #if (BITS_PER_LONG < 64)
+ u64 get_jiffies_64(void)
+@@ -82,9 +83,9 @@
+ 	u64 ret;
+ 
+ 	do {
+-		seq = read_seqbegin(&jiffies_lock);
++		seq = read_seqcount_begin(&jiffies_seq);
+ 		ret = jiffies_64;
+-	} while (read_seqretry(&jiffies_lock, seq));
++	} while (read_seqcount_retry(&jiffies_seq, seq));
+ 	return ret;
+ }
+ EXPORT_SYMBOL(get_jiffies_64);
+diff -Nur linux-3.18.8.orig/kernel/time/ntp.c linux-3.18.8/kernel/time/ntp.c
+--- linux-3.18.8.orig/kernel/time/ntp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/ntp.c	2015-03-03 08:05:18.000000000 +0100
+@@ -10,6 +10,7 @@
+ #include <linux/workqueue.h>
+ #include <linux/hrtimer.h>
+ #include <linux/jiffies.h>
++#include <linux/kthread.h>
+ #include <linux/math64.h>
+ #include <linux/timex.h>
+ #include <linux/time.h>
+@@ -519,10 +520,52 @@
+ 			   &sync_cmos_work, timespec_to_jiffies(&next));
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * RT can not call schedule_delayed_work from real interrupt context.
++ * Need to make a thread to do the real work.
++ */
++static struct task_struct *cmos_delay_thread;
++static bool do_cmos_delay;
++
++static int run_cmos_delay(void *ignore)
++{
++	while (!kthread_should_stop()) {
++		set_current_state(TASK_INTERRUPTIBLE);
++		if (do_cmos_delay) {
++			do_cmos_delay = false;
++			queue_delayed_work(system_power_efficient_wq,
++					   &sync_cmos_work, 0);
++		}
++		schedule();
++	}
++	__set_current_state(TASK_RUNNING);
++	return 0;
++}
++
++void ntp_notify_cmos_timer(void)
++{
++	do_cmos_delay = true;
++	/* Make visible before waking up process */
++	smp_wmb();
++	wake_up_process(cmos_delay_thread);
++}
++
++static __init int create_cmos_delay_thread(void)
++{
++	cmos_delay_thread = kthread_run(run_cmos_delay, NULL, "kcmosdelayd");
++	BUG_ON(!cmos_delay_thread);
++	return 0;
++}
++early_initcall(create_cmos_delay_thread);
++
++#else
++
+ void ntp_notify_cmos_timer(void)
+ {
+ 	queue_delayed_work(system_power_efficient_wq, &sync_cmos_work, 0);
+ }
++#endif /* CONFIG_PREEMPT_RT_FULL */
+ 
+ #else
+ void ntp_notify_cmos_timer(void) { }
+diff -Nur linux-3.18.8.orig/kernel/time/posix-cpu-timers.c linux-3.18.8/kernel/time/posix-cpu-timers.c
+--- linux-3.18.8.orig/kernel/time/posix-cpu-timers.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/posix-cpu-timers.c	2015-03-03 08:05:18.000000000 +0100
+@@ -3,6 +3,7 @@
+  */
+ 
+ #include <linux/sched.h>
++#include <linux/sched/rt.h>
+ #include <linux/posix-timers.h>
+ #include <linux/errno.h>
+ #include <linux/math64.h>
+@@ -626,7 +627,7 @@
+ 	/*
+ 	 * Disarm any old timer after extracting its expiry time.
+ 	 */
+-	WARN_ON_ONCE(!irqs_disabled());
++	WARN_ON_ONCE_NONRT(!irqs_disabled());
+ 
+ 	ret = 0;
+ 	old_incr = timer->it.cpu.incr;
+@@ -1047,7 +1048,7 @@
+ 	/*
+ 	 * Now re-arm for the new expiry time.
+ 	 */
+-	WARN_ON_ONCE(!irqs_disabled());
++	WARN_ON_ONCE_NONRT(!irqs_disabled());
+ 	arm_timer(timer);
+ 	unlock_task_sighand(p, &flags);
+ 
+@@ -1113,10 +1114,11 @@
+ 	sig = tsk->signal;
+ 	if (sig->cputimer.running) {
+ 		struct task_cputime group_sample;
++		unsigned long flags;
+ 
+-		raw_spin_lock(&sig->cputimer.lock);
++		raw_spin_lock_irqsave(&sig->cputimer.lock, flags);
+ 		group_sample = sig->cputimer.cputime;
+-		raw_spin_unlock(&sig->cputimer.lock);
++		raw_spin_unlock_irqrestore(&sig->cputimer.lock, flags);
+ 
+ 		if (task_cputime_expired(&group_sample, &sig->cputime_expires))
+ 			return 1;
+@@ -1130,13 +1132,13 @@
+  * already updated our counts.  We need to check if any timers fire now.
+  * Interrupts are disabled.
+  */
+-void run_posix_cpu_timers(struct task_struct *tsk)
++static void __run_posix_cpu_timers(struct task_struct *tsk)
+ {
+ 	LIST_HEAD(firing);
+ 	struct k_itimer *timer, *next;
+ 	unsigned long flags;
+ 
+-	WARN_ON_ONCE(!irqs_disabled());
++	WARN_ON_ONCE_NONRT(!irqs_disabled());
+ 
+ 	/*
+ 	 * The fast path checks that there are no expired thread or thread
+@@ -1194,6 +1196,190 @@
+ 	}
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++#include <linux/kthread.h>
++#include <linux/cpu.h>
++DEFINE_PER_CPU(struct task_struct *, posix_timer_task);
++DEFINE_PER_CPU(struct task_struct *, posix_timer_tasklist);
++
++static int posix_cpu_timers_thread(void *data)
++{
++	int cpu = (long)data;
++
++	BUG_ON(per_cpu(posix_timer_task,cpu) != current);
++
++	while (!kthread_should_stop()) {
++		struct task_struct *tsk = NULL;
++		struct task_struct *next = NULL;
++
++		if (cpu_is_offline(cpu))
++			goto wait_to_die;
++
++		/* grab task list */
++		raw_local_irq_disable();
++		tsk = per_cpu(posix_timer_tasklist, cpu);
++		per_cpu(posix_timer_tasklist, cpu) = NULL;
++		raw_local_irq_enable();
++
++		/* its possible the list is empty, just return */
++		if (!tsk) {
++			set_current_state(TASK_INTERRUPTIBLE);
++			schedule();
++			__set_current_state(TASK_RUNNING);
++			continue;
++		}
++
++		/* Process task list */
++		while (1) {
++			/* save next */
++			next = tsk->posix_timer_list;
++
++			/* run the task timers, clear its ptr and
++			 * unreference it
++			 */
++			__run_posix_cpu_timers(tsk);
++			tsk->posix_timer_list = NULL;
++			put_task_struct(tsk);
++
++			/* check if this is the last on the list */
++			if (next == tsk)
++				break;
++			tsk = next;
++		}
++	}
++	return 0;
++
++wait_to_die:
++	/* Wait for kthread_stop */
++	set_current_state(TASK_INTERRUPTIBLE);
++	while (!kthread_should_stop()) {
++		schedule();
++		set_current_state(TASK_INTERRUPTIBLE);
++	}
++	__set_current_state(TASK_RUNNING);
++	return 0;
++}
++
++static inline int __fastpath_timer_check(struct task_struct *tsk)
++{
++	/* tsk == current, ensure it is safe to use ->signal/sighand */
++	if (unlikely(tsk->exit_state))
++		return 0;
++
++	if (!task_cputime_zero(&tsk->cputime_expires))
++			return 1;
++
++	if (!task_cputime_zero(&tsk->signal->cputime_expires))
++			return 1;
++
++	return 0;
++}
++
++void run_posix_cpu_timers(struct task_struct *tsk)
++{
++	unsigned long cpu = smp_processor_id();
++	struct task_struct *tasklist;
++
++	BUG_ON(!irqs_disabled());
++	if(!per_cpu(posix_timer_task, cpu))
++		return;
++	/* get per-cpu references */
++	tasklist = per_cpu(posix_timer_tasklist, cpu);
++
++	/* check to see if we're already queued */
++	if (!tsk->posix_timer_list && __fastpath_timer_check(tsk)) {
++		get_task_struct(tsk);
++		if (tasklist) {
++			tsk->posix_timer_list = tasklist;
++		} else {
++			/*
++			 * The list is terminated by a self-pointing
++			 * task_struct
++			 */
++			tsk->posix_timer_list = tsk;
++		}
++		per_cpu(posix_timer_tasklist, cpu) = tsk;
++
++		wake_up_process(per_cpu(posix_timer_task, cpu));
++	}
++}
++
++/*
++ * posix_cpu_thread_call - callback that gets triggered when a CPU is added.
++ * Here we can start up the necessary migration thread for the new CPU.
++ */
++static int posix_cpu_thread_call(struct notifier_block *nfb,
++				 unsigned long action, void *hcpu)
++{
++	int cpu = (long)hcpu;
++	struct task_struct *p;
++	struct sched_param param;
++
++	switch (action) {
++	case CPU_UP_PREPARE:
++		p = kthread_create(posix_cpu_timers_thread, hcpu,
++					"posixcputmr/%d",cpu);
++		if (IS_ERR(p))
++			return NOTIFY_BAD;
++		p->flags |= PF_NOFREEZE;
++		kthread_bind(p, cpu);
++		/* Must be high prio to avoid getting starved */
++		param.sched_priority = MAX_RT_PRIO-1;
++		sched_setscheduler(p, SCHED_FIFO, &param);
++		per_cpu(posix_timer_task,cpu) = p;
++		break;
++	case CPU_ONLINE:
++		/* Strictly unneccessary, as first user will wake it. */
++		wake_up_process(per_cpu(posix_timer_task,cpu));
++		break;
++#ifdef CONFIG_HOTPLUG_CPU
++	case CPU_UP_CANCELED:
++		/* Unbind it from offline cpu so it can run.  Fall thru. */
++		kthread_bind(per_cpu(posix_timer_task, cpu),
++			     cpumask_any(cpu_online_mask));
++		kthread_stop(per_cpu(posix_timer_task,cpu));
++		per_cpu(posix_timer_task,cpu) = NULL;
++		break;
++	case CPU_DEAD:
++		kthread_stop(per_cpu(posix_timer_task,cpu));
++		per_cpu(posix_timer_task,cpu) = NULL;
++		break;
++#endif
++	}
++	return NOTIFY_OK;
++}
++
++/* Register at highest priority so that task migration (migrate_all_tasks)
++ * happens before everything else.
++ */
++static struct notifier_block posix_cpu_thread_notifier = {
++	.notifier_call = posix_cpu_thread_call,
++	.priority = 10
++};
++
++static int __init posix_cpu_thread_init(void)
++{
++	void *hcpu = (void *)(long)smp_processor_id();
++	/* Start one for boot CPU. */
++	unsigned long cpu;
++
++	/* init the per-cpu posix_timer_tasklets */
++	for_each_possible_cpu(cpu)
++		per_cpu(posix_timer_tasklist, cpu) = NULL;
++
++	posix_cpu_thread_call(&posix_cpu_thread_notifier, CPU_UP_PREPARE, hcpu);
++	posix_cpu_thread_call(&posix_cpu_thread_notifier, CPU_ONLINE, hcpu);
++	register_cpu_notifier(&posix_cpu_thread_notifier);
++	return 0;
++}
++early_initcall(posix_cpu_thread_init);
++#else /* CONFIG_PREEMPT_RT_BASE */
++void run_posix_cpu_timers(struct task_struct *tsk)
++{
++	__run_posix_cpu_timers(tsk);
++}
++#endif /* CONFIG_PREEMPT_RT_BASE */
++
+ /*
+  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
+  * The tsk->sighand->siglock must be held by the caller.
+diff -Nur linux-3.18.8.orig/kernel/time/posix-timers.c linux-3.18.8/kernel/time/posix-timers.c
+--- linux-3.18.8.orig/kernel/time/posix-timers.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/posix-timers.c	2015-03-03 08:05:18.000000000 +0100
+@@ -499,6 +499,7 @@
+ static struct pid *good_sigevent(sigevent_t * event)
+ {
+ 	struct task_struct *rtn = current->group_leader;
++	int sig = event->sigev_signo;
+ 
+ 	if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
+ 		(!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
+@@ -507,7 +508,8 @@
+ 		return NULL;
+ 
+ 	if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
+-	    ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
++	    (sig <= 0 || sig > SIGRTMAX || sig_kernel_only(sig) ||
++	     sig_kernel_coredump(sig)))
+ 		return NULL;
+ 
+ 	return task_pid(rtn);
+@@ -819,6 +821,20 @@
+ 	return overrun;
+ }
+ 
++/*
++ * Protected by RCU!
++ */
++static void timer_wait_for_callback(struct k_clock *kc, struct k_itimer *timr)
++{
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (kc->timer_set == common_timer_set)
++		hrtimer_wait_for_timer(&timr->it.real.timer);
++	else
++		/* FIXME: Whacky hack for posix-cpu-timers */
++		schedule_timeout(1);
++#endif
++}
++
+ /* Set a POSIX.1b interval timer. */
+ /* timr->it_lock is taken. */
+ static int
+@@ -896,6 +912,7 @@
+ 	if (!timr)
+ 		return -EINVAL;
+ 
++	rcu_read_lock();
+ 	kc = clockid_to_kclock(timr->it_clock);
+ 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
+ 		error = -EINVAL;
+@@ -904,9 +921,12 @@
+ 
+ 	unlock_timer(timr, flag);
+ 	if (error == TIMER_RETRY) {
++		timer_wait_for_callback(kc, timr);
+ 		rtn = NULL;	// We already got the old time...
++		rcu_read_unlock();
+ 		goto retry;
+ 	}
++	rcu_read_unlock();
+ 
+ 	if (old_setting && !error &&
+ 	    copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
+@@ -944,10 +964,15 @@
+ 	if (!timer)
+ 		return -EINVAL;
+ 
++	rcu_read_lock();
+ 	if (timer_delete_hook(timer) == TIMER_RETRY) {
+ 		unlock_timer(timer, flags);
++		timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
++					timer);
++		rcu_read_unlock();
+ 		goto retry_delete;
+ 	}
++	rcu_read_unlock();
+ 
+ 	spin_lock(&current->sighand->siglock);
+ 	list_del(&timer->list);
+@@ -973,8 +998,18 @@
+ retry_delete:
+ 	spin_lock_irqsave(&timer->it_lock, flags);
+ 
++	/* On RT we can race with a deletion */
++	if (!timer->it_signal) {
++		unlock_timer(timer, flags);
++		return;
++	}
++
+ 	if (timer_delete_hook(timer) == TIMER_RETRY) {
++		rcu_read_lock();
+ 		unlock_timer(timer, flags);
++		timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
++					timer);
++		rcu_read_unlock();
+ 		goto retry_delete;
+ 	}
+ 	list_del(&timer->list);
+diff -Nur linux-3.18.8.orig/kernel/time/tick-common.c linux-3.18.8/kernel/time/tick-common.c
+--- linux-3.18.8.orig/kernel/time/tick-common.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/tick-common.c	2015-03-03 08:05:18.000000000 +0100
+@@ -78,13 +78,15 @@
+ static void tick_periodic(int cpu)
+ {
+ 	if (tick_do_timer_cpu == cpu) {
+-		write_seqlock(&jiffies_lock);
++		raw_spin_lock(&jiffies_lock);
++		write_seqcount_begin(&jiffies_seq);
+ 
+ 		/* Keep track of the next tick event */
+ 		tick_next_period = ktime_add(tick_next_period, tick_period);
+ 
+ 		do_timer(1);
+-		write_sequnlock(&jiffies_lock);
++		write_seqcount_end(&jiffies_seq);
++		raw_spin_unlock(&jiffies_lock);
+ 		update_wall_time();
+ 	}
+ 
+@@ -146,9 +148,9 @@
+ 		ktime_t next;
+ 
+ 		do {
+-			seq = read_seqbegin(&jiffies_lock);
++			seq = read_seqcount_begin(&jiffies_seq);
+ 			next = tick_next_period;
+-		} while (read_seqretry(&jiffies_lock, seq));
++		} while (read_seqcount_retry(&jiffies_seq, seq));
+ 
+ 		clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
+ 
+diff -Nur linux-3.18.8.orig/kernel/time/tick-internal.h linux-3.18.8/kernel/time/tick-internal.h
+--- linux-3.18.8.orig/kernel/time/tick-internal.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/tick-internal.h	2015-03-03 08:05:18.000000000 +0100
+@@ -6,7 +6,8 @@
+ 
+ #include "timekeeping.h"
+ 
+-extern seqlock_t jiffies_lock;
++extern raw_spinlock_t jiffies_lock;
++extern seqcount_t jiffies_seq;
+ 
+ #define CS_NAME_LEN	32
+ 
+diff -Nur linux-3.18.8.orig/kernel/time/tick-sched.c linux-3.18.8/kernel/time/tick-sched.c
+--- linux-3.18.8.orig/kernel/time/tick-sched.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/tick-sched.c	2015-03-03 08:05:18.000000000 +0100
+@@ -62,7 +62,8 @@
+ 		return;
+ 
+ 	/* Reevalute with jiffies_lock held */
+-	write_seqlock(&jiffies_lock);
++	raw_spin_lock(&jiffies_lock);
++	write_seqcount_begin(&jiffies_seq);
+ 
+ 	delta = ktime_sub(now, last_jiffies_update);
+ 	if (delta.tv64 >= tick_period.tv64) {
+@@ -85,10 +86,12 @@
+ 		/* Keep the tick_next_period variable up to date */
+ 		tick_next_period = ktime_add(last_jiffies_update, tick_period);
+ 	} else {
+-		write_sequnlock(&jiffies_lock);
++		write_seqcount_end(&jiffies_seq);
++		raw_spin_unlock(&jiffies_lock);
+ 		return;
+ 	}
+-	write_sequnlock(&jiffies_lock);
++	write_seqcount_end(&jiffies_seq);
++	raw_spin_unlock(&jiffies_lock);
+ 	update_wall_time();
+ }
+ 
+@@ -99,12 +102,14 @@
+ {
+ 	ktime_t period;
+ 
+-	write_seqlock(&jiffies_lock);
++	raw_spin_lock(&jiffies_lock);
++	write_seqcount_begin(&jiffies_seq);
+ 	/* Did we start the jiffies update yet ? */
+ 	if (last_jiffies_update.tv64 == 0)
+ 		last_jiffies_update = tick_next_period;
+ 	period = last_jiffies_update;
+-	write_sequnlock(&jiffies_lock);
++	write_seqcount_end(&jiffies_seq);
++	raw_spin_unlock(&jiffies_lock);
+ 	return period;
+ }
+ 
+@@ -222,6 +227,7 @@
+ 
+ static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = {
+ 	.func = nohz_full_kick_work_func,
++	.flags = IRQ_WORK_HARD_IRQ,
+ };
+ 
+ /*
+@@ -580,10 +586,10 @@
+ 
+ 	/* Read jiffies and the time when jiffies were updated last */
+ 	do {
+-		seq = read_seqbegin(&jiffies_lock);
++		seq = read_seqcount_begin(&jiffies_seq);
+ 		last_update = last_jiffies_update;
+ 		last_jiffies = jiffies;
+-	} while (read_seqretry(&jiffies_lock, seq));
++	} while (read_seqcount_retry(&jiffies_seq, seq));
+ 
+ 	if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) ||
+ 	    arch_needs_cpu() || irq_work_needs_cpu()) {
+@@ -761,14 +767,7 @@
+ 		return false;
+ 
+ 	if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
+-		static int ratelimit;
+-
+-		if (ratelimit < 10 &&
+-		    (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) {
+-			pr_warn("NOHZ: local_softirq_pending %02x\n",
+-				(unsigned int) local_softirq_pending());
+-			ratelimit++;
+-		}
++		softirq_check_pending_idle();
+ 		return false;
+ 	}
+ 
+@@ -1156,6 +1155,7 @@
+ 	 * Emulate tick processing via per-CPU hrtimers:
+ 	 */
+ 	hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
++	ts->sched_timer.irqsafe = 1;
+ 	ts->sched_timer.function = tick_sched_timer;
+ 
+ 	/* Get the next period (per cpu) */
+diff -Nur linux-3.18.8.orig/kernel/time/timekeeping.c linux-3.18.8/kernel/time/timekeeping.c
+--- linux-3.18.8.orig/kernel/time/timekeeping.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/timekeeping.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1814,8 +1814,10 @@
+  */
+ void xtime_update(unsigned long ticks)
+ {
+-	write_seqlock(&jiffies_lock);
++	raw_spin_lock(&jiffies_lock);
++	write_seqcount_begin(&jiffies_seq);
+ 	do_timer(ticks);
+-	write_sequnlock(&jiffies_lock);
++	write_seqcount_end(&jiffies_seq);
++	raw_spin_unlock(&jiffies_lock);
+ 	update_wall_time();
+ }
+diff -Nur linux-3.18.8.orig/kernel/time/timer.c linux-3.18.8/kernel/time/timer.c
+--- linux-3.18.8.orig/kernel/time/timer.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/time/timer.c	2015-03-03 08:05:18.000000000 +0100
+@@ -78,6 +78,9 @@
+ struct tvec_base {
+ 	spinlock_t lock;
+ 	struct timer_list *running_timer;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	wait_queue_head_t wait_for_running_timer;
++#endif
+ 	unsigned long timer_jiffies;
+ 	unsigned long next_timer;
+ 	unsigned long active_timers;
+@@ -758,6 +761,36 @@
+ 	}
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
++static inline struct tvec_base *switch_timer_base(struct timer_list *timer,
++						  struct tvec_base *old,
++						  struct tvec_base *new)
++{
++	/* See the comment in lock_timer_base() */
++	timer_set_base(timer, NULL);
++	spin_unlock(&old->lock);
++	spin_lock(&new->lock);
++	timer_set_base(timer, new);
++	return new;
++}
++#else
++static inline struct tvec_base *switch_timer_base(struct timer_list *timer,
++						  struct tvec_base *old,
++						  struct tvec_base *new)
++{
++	/*
++	 * We cannot do the above because we might be preempted and
++	 * then the preempter would see NULL and loop forever.
++	 */
++	if (spin_trylock(&new->lock)) {
++		timer_set_base(timer, new);
++		spin_unlock(&old->lock);
++		return new;
++	}
++	return old;
++}
++#endif
++
+ static inline int
+ __mod_timer(struct timer_list *timer, unsigned long expires,
+ 						bool pending_only, int pinned)
+@@ -788,14 +821,8 @@
+ 		 * handler yet has not finished. This also guarantees that
+ 		 * the timer is serialized wrt itself.
+ 		 */
+-		if (likely(base->running_timer != timer)) {
+-			/* See the comment in lock_timer_base() */
+-			timer_set_base(timer, NULL);
+-			spin_unlock(&base->lock);
+-			base = new_base;
+-			spin_lock(&base->lock);
+-			timer_set_base(timer, base);
+-		}
++		if (likely(base->running_timer != timer))
++			base = switch_timer_base(timer, base, new_base);
+ 	}
+ 
+ 	timer->expires = expires;
+@@ -969,6 +996,29 @@
+ }
+ EXPORT_SYMBOL_GPL(add_timer_on);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * Wait for a running timer
++ */
++static void wait_for_running_timer(struct timer_list *timer)
++{
++	struct tvec_base *base = timer->base;
++
++	if (base->running_timer == timer)
++		wait_event(base->wait_for_running_timer,
++			   base->running_timer != timer);
++}
++
++# define wakeup_timer_waiters(b)	wake_up(&(b)->wait_for_running_timer)
++#else
++static inline void wait_for_running_timer(struct timer_list *timer)
++{
++	cpu_relax();
++}
++
++# define wakeup_timer_waiters(b)	do { } while (0)
++#endif
++
+ /**
+  * del_timer - deactive a timer.
+  * @timer: the timer to be deactivated
+@@ -1026,7 +1076,7 @@
+ }
+ EXPORT_SYMBOL(try_to_del_timer_sync);
+ 
+-#ifdef CONFIG_SMP
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
+ /**
+  * del_timer_sync - deactivate a timer and wait for the handler to finish.
+  * @timer: the timer to be deactivated
+@@ -1086,7 +1136,7 @@
+ 		int ret = try_to_del_timer_sync(timer);
+ 		if (ret >= 0)
+ 			return ret;
+-		cpu_relax();
++		wait_for_running_timer(timer);
+ 	}
+ }
+ EXPORT_SYMBOL(del_timer_sync);
+@@ -1207,15 +1257,17 @@
+ 			if (irqsafe) {
+ 				spin_unlock(&base->lock);
+ 				call_timer_fn(timer, fn, data);
++				base->running_timer = NULL;
+ 				spin_lock(&base->lock);
+ 			} else {
+ 				spin_unlock_irq(&base->lock);
+ 				call_timer_fn(timer, fn, data);
++				base->running_timer = NULL;
+ 				spin_lock_irq(&base->lock);
+ 			}
+ 		}
+ 	}
+-	base->running_timer = NULL;
++	wakeup_timer_waiters(base);
+ 	spin_unlock_irq(&base->lock);
+ }
+ 
+@@ -1355,17 +1407,31 @@
+ 	if (cpu_is_offline(smp_processor_id()))
+ 		return expires;
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++	/*
++	 * On PREEMPT_RT we cannot sleep here. If the trylock does not
++	 * succeed then we return the worst-case 'expires in 1 tick'
++	 * value.  We use the rt functions here directly to avoid a
++	 * migrate_disable() call.
++	 */
++	if (!spin_do_trylock(&base->lock))
++		return  now + 1;
++#else
+ 	spin_lock(&base->lock);
++#endif
+ 	if (base->active_timers) {
+ 		if (time_before_eq(base->next_timer, base->timer_jiffies))
+ 			base->next_timer = __next_timer_interrupt(base);
+ 		expires = base->next_timer;
+ 	}
++#ifdef CONFIG_PREEMPT_RT_FULL
++	rt_spin_unlock_after_trylock_in_irq(&base->lock);
++#else
+ 	spin_unlock(&base->lock);
++#endif
+ 
+ 	if (time_before_eq(expires, now))
+ 		return now;
+-
+ 	return cmp_next_hrtimer_event(now, expires);
+ }
+ #endif
+@@ -1381,13 +1447,13 @@
+ 
+ 	/* Note: this timer irq context must be accounted for as well. */
+ 	account_process_tick(p, user_tick);
++	scheduler_tick();
+ 	run_local_timers();
+ 	rcu_check_callbacks(cpu, user_tick);
+ #ifdef CONFIG_IRQ_WORK
+ 	if (in_irq())
+ 		irq_work_tick();
+ #endif
+-	scheduler_tick();
+ 	run_posix_cpu_timers(p);
+ }
+ 
+@@ -1400,6 +1466,10 @@
+ 
+ 	hrtimer_run_pending();
+ 
++#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
++	irq_work_tick();
++#endif
++
+ 	if (time_after_eq(jiffies, base->timer_jiffies))
+ 		__run_timers(base);
+ }
+@@ -1574,6 +1644,9 @@
+ 		base = per_cpu(tvec_bases, cpu);
+ 	}
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++	init_waitqueue_head(&base->wait_for_running_timer);
++#endif
+ 
+ 	for (j = 0; j < TVN_SIZE; j++) {
+ 		INIT_LIST_HEAD(base->tv5.vec + j);
+@@ -1613,7 +1686,7 @@
+ 
+ 	BUG_ON(cpu_online(cpu));
+ 	old_base = per_cpu(tvec_bases, cpu);
+-	new_base = get_cpu_var(tvec_bases);
++	new_base = get_local_var(tvec_bases);
+ 	/*
+ 	 * The caller is globally serialized and nobody else
+ 	 * takes two locks at once, deadlock is not possible.
+@@ -1634,7 +1707,7 @@
+ 
+ 	spin_unlock(&old_base->lock);
+ 	spin_unlock_irq(&new_base->lock);
+-	put_cpu_var(tvec_bases);
++	put_local_var(tvec_bases);
+ }
+ #endif /* CONFIG_HOTPLUG_CPU */
+ 
+diff -Nur linux-3.18.8.orig/kernel/trace/Kconfig linux-3.18.8/kernel/trace/Kconfig
+--- linux-3.18.8.orig/kernel/trace/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -187,6 +187,24 @@
+ 	  enabled. This option and the preempt-off timing option can be
+ 	  used together or separately.)
+ 
++config INTERRUPT_OFF_HIST
++	bool "Interrupts-off Latency Histogram"
++	depends on IRQSOFF_TRACER
++	help
++	  This option generates continuously updated histograms (one per cpu)
++	  of the duration of time periods with interrupts disabled. The
++	  histograms are disabled by default. To enable them, write a non-zero
++	  number to
++
++	      /sys/kernel/debug/tracing/latency_hist/enable/preemptirqsoff
++
++	  If PREEMPT_OFF_HIST is also selected, additional histograms (one
++	  per cpu) are generated that accumulate the duration of time periods
++	  when both interrupts and preemption are disabled. The histogram data
++	  will be located in the debug file system at
++
++	      /sys/kernel/debug/tracing/latency_hist/irqsoff
++
+ config PREEMPT_TRACER
+ 	bool "Preemption-off Latency Tracer"
+ 	default n
+@@ -211,6 +229,24 @@
+ 	  enabled. This option and the irqs-off timing option can be
+ 	  used together or separately.)
+ 
++config PREEMPT_OFF_HIST
++	bool "Preemption-off Latency Histogram"
++	depends on PREEMPT_TRACER
++	help
++	  This option generates continuously updated histograms (one per cpu)
++	  of the duration of time periods with preemption disabled. The
++	  histograms are disabled by default. To enable them, write a non-zero
++	  number to
++
++	      /sys/kernel/debug/tracing/latency_hist/enable/preemptirqsoff
++
++	  If INTERRUPT_OFF_HIST is also selected, additional histograms (one
++	  per cpu) are generated that accumulate the duration of time periods
++	  when both interrupts and preemption are disabled. The histogram data
++	  will be located in the debug file system at
++
++	      /sys/kernel/debug/tracing/latency_hist/preemptoff
++
+ config SCHED_TRACER
+ 	bool "Scheduling Latency Tracer"
+ 	select GENERIC_TRACER
+@@ -221,6 +257,74 @@
+ 	  This tracer tracks the latency of the highest priority task
+ 	  to be scheduled in, starting from the point it has woken up.
+ 
++config WAKEUP_LATENCY_HIST
++	bool "Scheduling Latency Histogram"
++	depends on SCHED_TRACER
++	help
++	  This option generates continuously updated histograms (one per cpu)
++	  of the scheduling latency of the highest priority task.
++	  The histograms are disabled by default. To enable them, write a
++	  non-zero number to
++
++	      /sys/kernel/debug/tracing/latency_hist/enable/wakeup
++
++	  Two different algorithms are used, one to determine the latency of
++	  processes that exclusively use the highest priority of the system and
++	  another one to determine the latency of processes that share the
++	  highest system priority with other processes. The former is used to
++	  improve hardware and system software, the latter to optimize the
++	  priority design of a given system. The histogram data will be
++	  located in the debug file system at
++
++	      /sys/kernel/debug/tracing/latency_hist/wakeup
++
++	  and
++
++	      /sys/kernel/debug/tracing/latency_hist/wakeup/sharedprio
++
++	  If both Scheduling Latency Histogram and Missed Timer Offsets
++	  Histogram are selected, additional histogram data will be collected
++	  that contain, in addition to the wakeup latency, the timer latency, in
++	  case the wakeup was triggered by an expired timer. These histograms
++	  are available in the
++
++	      /sys/kernel/debug/tracing/latency_hist/timerandwakeup
++
++	  directory. They reflect the apparent interrupt and scheduling latency
++	  and are best suitable to determine the worst-case latency of a given
++	  system. To enable these histograms, write a non-zero number to
++
++	      /sys/kernel/debug/tracing/latency_hist/enable/timerandwakeup
++
++config MISSED_TIMER_OFFSETS_HIST
++	depends on HIGH_RES_TIMERS
++	select GENERIC_TRACER
++	bool "Missed Timer Offsets Histogram"
++	help
++	  Generate a histogram of missed timer offsets in microseconds. The
++	  histograms are disabled by default. To enable them, write a non-zero
++	  number to
++
++	      /sys/kernel/debug/tracing/latency_hist/enable/missed_timer_offsets
++
++	  The histogram data will be located in the debug file system at
++
++	      /sys/kernel/debug/tracing/latency_hist/missed_timer_offsets
++
++	  If both Scheduling Latency Histogram and Missed Timer Offsets
++	  Histogram are selected, additional histogram data will be collected
++	  that contain, in addition to the wakeup latency, the timer latency, in
++	  case the wakeup was triggered by an expired timer. These histograms
++	  are available in the
++
++	      /sys/kernel/debug/tracing/latency_hist/timerandwakeup
++
++	  directory. They reflect the apparent interrupt and scheduling latency
++	  and are best suitable to determine the worst-case latency of a given
++	  system. To enable these histograms, write a non-zero number to
++
++	      /sys/kernel/debug/tracing/latency_hist/enable/timerandwakeup
++
+ config ENABLE_DEFAULT_TRACERS
+ 	bool "Trace process context switches and events"
+ 	depends on !GENERIC_TRACER
+diff -Nur linux-3.18.8.orig/kernel/trace/latency_hist.c linux-3.18.8/kernel/trace/latency_hist.c
+--- linux-3.18.8.orig/kernel/trace/latency_hist.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-3.18.8/kernel/trace/latency_hist.c	2015-03-03 08:05:18.000000000 +0100
+@@ -0,0 +1,1178 @@
++/*
++ * kernel/trace/latency_hist.c
++ *
++ * Add support for histograms of preemption-off latency and
++ * interrupt-off latency and wakeup latency, it depends on
++ * Real-Time Preemption Support.
++ *
++ *  Copyright (C) 2005 MontaVista Software, Inc.
++ *  Yi Yang <yyang@ch.mvista.com>
++ *
++ *  Converted to work with the new latency tracer.
++ *  Copyright (C) 2008 Red Hat, Inc.
++ *    Steven Rostedt <srostedt@redhat.com>
++ *
++ */
++#include <linux/module.h>
++#include <linux/debugfs.h>
++#include <linux/seq_file.h>
++#include <linux/percpu.h>
++#include <linux/kallsyms.h>
++#include <linux/uaccess.h>
++#include <linux/sched.h>
++#include <linux/sched/rt.h>
++#include <linux/slab.h>
++#include <linux/atomic.h>
++#include <asm/div64.h>
++
++#include "trace.h"
++#include <trace/events/sched.h>
++
++#define NSECS_PER_USECS 1000L
++
++#define CREATE_TRACE_POINTS
++#include <trace/events/hist.h>
++
++enum {
++	IRQSOFF_LATENCY = 0,
++	PREEMPTOFF_LATENCY,
++	PREEMPTIRQSOFF_LATENCY,
++	WAKEUP_LATENCY,
++	WAKEUP_LATENCY_SHAREDPRIO,
++	MISSED_TIMER_OFFSETS,
++	TIMERANDWAKEUP_LATENCY,
++	MAX_LATENCY_TYPE,
++};
++
++#define MAX_ENTRY_NUM 10240
++
++struct hist_data {
++	atomic_t hist_mode; /* 0 log, 1 don't log */
++	long offset; /* set it to MAX_ENTRY_NUM/2 for a bipolar scale */
++	long min_lat;
++	long max_lat;
++	unsigned long long below_hist_bound_samples;
++	unsigned long long above_hist_bound_samples;
++	long long accumulate_lat;
++	unsigned long long total_samples;
++	unsigned long long hist_array[MAX_ENTRY_NUM];
++};
++
++struct enable_data {
++	int latency_type;
++	int enabled;
++};
++
++static char *latency_hist_dir_root = "latency_hist";
++
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++static DEFINE_PER_CPU(struct hist_data, irqsoff_hist);
++static char *irqsoff_hist_dir = "irqsoff";
++static DEFINE_PER_CPU(cycles_t, hist_irqsoff_start);
++static DEFINE_PER_CPU(int, hist_irqsoff_counting);
++#endif
++
++#ifdef CONFIG_PREEMPT_OFF_HIST
++static DEFINE_PER_CPU(struct hist_data, preemptoff_hist);
++static char *preemptoff_hist_dir = "preemptoff";
++static DEFINE_PER_CPU(cycles_t, hist_preemptoff_start);
++static DEFINE_PER_CPU(int, hist_preemptoff_counting);
++#endif
++
++#if defined(CONFIG_PREEMPT_OFF_HIST) && defined(CONFIG_INTERRUPT_OFF_HIST)
++static DEFINE_PER_CPU(struct hist_data, preemptirqsoff_hist);
++static char *preemptirqsoff_hist_dir = "preemptirqsoff";
++static DEFINE_PER_CPU(cycles_t, hist_preemptirqsoff_start);
++static DEFINE_PER_CPU(int, hist_preemptirqsoff_counting);
++#endif
++
++#if defined(CONFIG_PREEMPT_OFF_HIST) || defined(CONFIG_INTERRUPT_OFF_HIST)
++static notrace void probe_preemptirqsoff_hist(void *v, int reason, int start);
++static struct enable_data preemptirqsoff_enabled_data = {
++	.latency_type = PREEMPTIRQSOFF_LATENCY,
++	.enabled = 0,
++};
++#endif
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++struct maxlatproc_data {
++	char comm[FIELD_SIZEOF(struct task_struct, comm)];
++	char current_comm[FIELD_SIZEOF(struct task_struct, comm)];
++	int pid;
++	int current_pid;
++	int prio;
++	int current_prio;
++	long latency;
++	long timeroffset;
++	cycle_t timestamp;
++};
++#endif
++
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++static DEFINE_PER_CPU(struct hist_data, wakeup_latency_hist);
++static DEFINE_PER_CPU(struct hist_data, wakeup_latency_hist_sharedprio);
++static char *wakeup_latency_hist_dir = "wakeup";
++static char *wakeup_latency_hist_dir_sharedprio = "sharedprio";
++static notrace void probe_wakeup_latency_hist_start(void *v,
++	struct task_struct *p, int success);
++static notrace void probe_wakeup_latency_hist_stop(void *v,
++	struct task_struct *prev, struct task_struct *next);
++static notrace void probe_sched_migrate_task(void *,
++	struct task_struct *task, int cpu);
++static struct enable_data wakeup_latency_enabled_data = {
++	.latency_type = WAKEUP_LATENCY,
++	.enabled = 0,
++};
++static DEFINE_PER_CPU(struct maxlatproc_data, wakeup_maxlatproc);
++static DEFINE_PER_CPU(struct maxlatproc_data, wakeup_maxlatproc_sharedprio);
++static DEFINE_PER_CPU(struct task_struct *, wakeup_task);
++static DEFINE_PER_CPU(int, wakeup_sharedprio);
++static unsigned long wakeup_pid;
++#endif
++
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++static DEFINE_PER_CPU(struct hist_data, missed_timer_offsets);
++static char *missed_timer_offsets_dir = "missed_timer_offsets";
++static notrace void probe_hrtimer_interrupt(void *v, int cpu,
++	long long offset, struct task_struct *curr, struct task_struct *task);
++static struct enable_data missed_timer_offsets_enabled_data = {
++	.latency_type = MISSED_TIMER_OFFSETS,
++	.enabled = 0,
++};
++static DEFINE_PER_CPU(struct maxlatproc_data, missed_timer_offsets_maxlatproc);
++static unsigned long missed_timer_offsets_pid;
++#endif
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++static DEFINE_PER_CPU(struct hist_data, timerandwakeup_latency_hist);
++static char *timerandwakeup_latency_hist_dir = "timerandwakeup";
++static struct enable_data timerandwakeup_enabled_data = {
++	.latency_type = TIMERANDWAKEUP_LATENCY,
++	.enabled = 0,
++};
++static DEFINE_PER_CPU(struct maxlatproc_data, timerandwakeup_maxlatproc);
++#endif
++
++void notrace latency_hist(int latency_type, int cpu, long latency,
++			  long timeroffset, cycle_t stop,
++			  struct task_struct *p)
++{
++	struct hist_data *my_hist;
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++	struct maxlatproc_data *mp = NULL;
++#endif
++
++	if (!cpu_possible(cpu) || latency_type < 0 ||
++	    latency_type >= MAX_LATENCY_TYPE)
++		return;
++
++	switch (latency_type) {
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++	case IRQSOFF_LATENCY:
++		my_hist = &per_cpu(irqsoff_hist, cpu);
++		break;
++#endif
++#ifdef CONFIG_PREEMPT_OFF_HIST
++	case PREEMPTOFF_LATENCY:
++		my_hist = &per_cpu(preemptoff_hist, cpu);
++		break;
++#endif
++#if defined(CONFIG_PREEMPT_OFF_HIST) && defined(CONFIG_INTERRUPT_OFF_HIST)
++	case PREEMPTIRQSOFF_LATENCY:
++		my_hist = &per_cpu(preemptirqsoff_hist, cpu);
++		break;
++#endif
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++	case WAKEUP_LATENCY:
++		my_hist = &per_cpu(wakeup_latency_hist, cpu);
++		mp = &per_cpu(wakeup_maxlatproc, cpu);
++		break;
++	case WAKEUP_LATENCY_SHAREDPRIO:
++		my_hist = &per_cpu(wakeup_latency_hist_sharedprio, cpu);
++		mp = &per_cpu(wakeup_maxlatproc_sharedprio, cpu);
++		break;
++#endif
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++	case MISSED_TIMER_OFFSETS:
++		my_hist = &per_cpu(missed_timer_offsets, cpu);
++		mp = &per_cpu(missed_timer_offsets_maxlatproc, cpu);
++		break;
++#endif
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++	case TIMERANDWAKEUP_LATENCY:
++		my_hist = &per_cpu(timerandwakeup_latency_hist, cpu);
++		mp = &per_cpu(timerandwakeup_maxlatproc, cpu);
++		break;
++#endif
++
++	default:
++		return;
++	}
++
++	latency += my_hist->offset;
++
++	if (atomic_read(&my_hist->hist_mode) == 0)
++		return;
++
++	if (latency < 0 || latency >= MAX_ENTRY_NUM) {
++		if (latency < 0)
++			my_hist->below_hist_bound_samples++;
++		else
++			my_hist->above_hist_bound_samples++;
++	} else
++		my_hist->hist_array[latency]++;
++
++	if (unlikely(latency > my_hist->max_lat ||
++	    my_hist->min_lat == LONG_MAX)) {
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++		if (latency_type == WAKEUP_LATENCY ||
++		    latency_type == WAKEUP_LATENCY_SHAREDPRIO ||
++		    latency_type == MISSED_TIMER_OFFSETS ||
++		    latency_type == TIMERANDWAKEUP_LATENCY) {
++			strncpy(mp->comm, p->comm, sizeof(mp->comm));
++			strncpy(mp->current_comm, current->comm,
++			    sizeof(mp->current_comm));
++			mp->pid = task_pid_nr(p);
++			mp->current_pid = task_pid_nr(current);
++			mp->prio = p->prio;
++			mp->current_prio = current->prio;
++			mp->latency = latency;
++			mp->timeroffset = timeroffset;
++			mp->timestamp = stop;
++		}
++#endif
++		my_hist->max_lat = latency;
++	}
++	if (unlikely(latency < my_hist->min_lat))
++		my_hist->min_lat = latency;
++	my_hist->total_samples++;
++	my_hist->accumulate_lat += latency;
++}
++
++static void *l_start(struct seq_file *m, loff_t *pos)
++{
++	loff_t *index_ptr = NULL;
++	loff_t index = *pos;
++	struct hist_data *my_hist = m->private;
++
++	if (index == 0) {
++		char minstr[32], avgstr[32], maxstr[32];
++
++		atomic_dec(&my_hist->hist_mode);
++
++		if (likely(my_hist->total_samples)) {
++			long avg = (long) div64_s64(my_hist->accumulate_lat,
++			    my_hist->total_samples);
++			snprintf(minstr, sizeof(minstr), "%ld",
++			    my_hist->min_lat - my_hist->offset);
++			snprintf(avgstr, sizeof(avgstr), "%ld",
++			    avg - my_hist->offset);
++			snprintf(maxstr, sizeof(maxstr), "%ld",
++			    my_hist->max_lat - my_hist->offset);
++		} else {
++			strcpy(minstr, "<undef>");
++			strcpy(avgstr, minstr);
++			strcpy(maxstr, minstr);
++		}
++
++		seq_printf(m, "#Minimum latency: %s microseconds\n"
++			   "#Average latency: %s microseconds\n"
++			   "#Maximum latency: %s microseconds\n"
++			   "#Total samples: %llu\n"
++			   "#There are %llu samples lower than %ld"
++			   " microseconds.\n"
++			   "#There are %llu samples greater or equal"
++			   " than %ld microseconds.\n"
++			   "#usecs\t%16s\n",
++			   minstr, avgstr, maxstr,
++			   my_hist->total_samples,
++			   my_hist->below_hist_bound_samples,
++			   -my_hist->offset,
++			   my_hist->above_hist_bound_samples,
++			   MAX_ENTRY_NUM - my_hist->offset,
++			   "samples");
++	}
++	if (index < MAX_ENTRY_NUM) {
++		index_ptr = kmalloc(sizeof(loff_t), GFP_KERNEL);
++		if (index_ptr)
++			*index_ptr = index;
++	}
++
++	return index_ptr;
++}
++
++static void *l_next(struct seq_file *m, void *p, loff_t *pos)
++{
++	loff_t *index_ptr = p;
++	struct hist_data *my_hist = m->private;
++
++	if (++*pos >= MAX_ENTRY_NUM) {
++		atomic_inc(&my_hist->hist_mode);
++		return NULL;
++	}
++	*index_ptr = *pos;
++	return index_ptr;
++}
++
++static void l_stop(struct seq_file *m, void *p)
++{
++	kfree(p);
++}
++
++static int l_show(struct seq_file *m, void *p)
++{
++	int index = *(loff_t *) p;
++	struct hist_data *my_hist = m->private;
++
++	seq_printf(m, "%6ld\t%16llu\n", index - my_hist->offset,
++	    my_hist->hist_array[index]);
++	return 0;
++}
++
++static const struct seq_operations latency_hist_seq_op = {
++	.start = l_start,
++	.next  = l_next,
++	.stop  = l_stop,
++	.show  = l_show
++};
++
++static int latency_hist_open(struct inode *inode, struct file *file)
++{
++	int ret;
++
++	ret = seq_open(file, &latency_hist_seq_op);
++	if (!ret) {
++		struct seq_file *seq = file->private_data;
++		seq->private = inode->i_private;
++	}
++	return ret;
++}
++
++static const struct file_operations latency_hist_fops = {
++	.open = latency_hist_open,
++	.read = seq_read,
++	.llseek = seq_lseek,
++	.release = seq_release,
++};
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++static void clear_maxlatprocdata(struct maxlatproc_data *mp)
++{
++	mp->comm[0] = mp->current_comm[0] = '\0';
++	mp->prio = mp->current_prio = mp->pid = mp->current_pid =
++	    mp->latency = mp->timeroffset = -1;
++	mp->timestamp = 0;
++}
++#endif
++
++static void hist_reset(struct hist_data *hist)
++{
++	atomic_dec(&hist->hist_mode);
++
++	memset(hist->hist_array, 0, sizeof(hist->hist_array));
++	hist->below_hist_bound_samples = 0ULL;
++	hist->above_hist_bound_samples = 0ULL;
++	hist->min_lat = LONG_MAX;
++	hist->max_lat = LONG_MIN;
++	hist->total_samples = 0ULL;
++	hist->accumulate_lat = 0LL;
++
++	atomic_inc(&hist->hist_mode);
++}
++
++static ssize_t
++latency_hist_reset(struct file *file, const char __user *a,
++		   size_t size, loff_t *off)
++{
++	int cpu;
++	struct hist_data *hist = NULL;
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++	struct maxlatproc_data *mp = NULL;
++#endif
++	off_t latency_type = (off_t) file->private_data;
++
++	for_each_online_cpu(cpu) {
++
++		switch (latency_type) {
++#ifdef CONFIG_PREEMPT_OFF_HIST
++		case PREEMPTOFF_LATENCY:
++			hist = &per_cpu(preemptoff_hist, cpu);
++			break;
++#endif
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++		case IRQSOFF_LATENCY:
++			hist = &per_cpu(irqsoff_hist, cpu);
++			break;
++#endif
++#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
++		case PREEMPTIRQSOFF_LATENCY:
++			hist = &per_cpu(preemptirqsoff_hist, cpu);
++			break;
++#endif
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++		case WAKEUP_LATENCY:
++			hist = &per_cpu(wakeup_latency_hist, cpu);
++			mp = &per_cpu(wakeup_maxlatproc, cpu);
++			break;
++		case WAKEUP_LATENCY_SHAREDPRIO:
++			hist = &per_cpu(wakeup_latency_hist_sharedprio, cpu);
++			mp = &per_cpu(wakeup_maxlatproc_sharedprio, cpu);
++			break;
++#endif
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++		case MISSED_TIMER_OFFSETS:
++			hist = &per_cpu(missed_timer_offsets, cpu);
++			mp = &per_cpu(missed_timer_offsets_maxlatproc, cpu);
++			break;
++#endif
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++		case TIMERANDWAKEUP_LATENCY:
++			hist = &per_cpu(timerandwakeup_latency_hist, cpu);
++			mp = &per_cpu(timerandwakeup_maxlatproc, cpu);
++			break;
++#endif
++		}
++
++		hist_reset(hist);
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++		if (latency_type == WAKEUP_LATENCY ||
++		    latency_type == WAKEUP_LATENCY_SHAREDPRIO ||
++		    latency_type == MISSED_TIMER_OFFSETS ||
++		    latency_type == TIMERANDWAKEUP_LATENCY)
++			clear_maxlatprocdata(mp);
++#endif
++	}
++
++	return size;
++}
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++static ssize_t
++show_pid(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos)
++{
++	char buf[64];
++	int r;
++	unsigned long *this_pid = file->private_data;
++
++	r = snprintf(buf, sizeof(buf), "%lu\n", *this_pid);
++	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
++}
++
++static ssize_t do_pid(struct file *file, const char __user *ubuf,
++		      size_t cnt, loff_t *ppos)
++{
++	char buf[64];
++	unsigned long pid;
++	unsigned long *this_pid = file->private_data;
++
++	if (cnt >= sizeof(buf))
++		return -EINVAL;
++
++	if (copy_from_user(&buf, ubuf, cnt))
++		return -EFAULT;
++
++	buf[cnt] = '\0';
++
++	if (kstrtoul(buf, 10, &pid))
++		return -EINVAL;
++
++	*this_pid = pid;
++
++	return cnt;
++}
++#endif
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++static ssize_t
++show_maxlatproc(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos)
++{
++	int r;
++	struct maxlatproc_data *mp = file->private_data;
++	int strmaxlen = (TASK_COMM_LEN * 2) + (8 * 8);
++	unsigned long long t;
++	unsigned long usecs, secs;
++	char *buf;
++
++	if (mp->pid == -1 || mp->current_pid == -1) {
++		buf = "(none)\n";
++		return simple_read_from_buffer(ubuf, cnt, ppos, buf,
++		    strlen(buf));
++	}
++
++	buf = kmalloc(strmaxlen, GFP_KERNEL);
++	if (buf == NULL)
++		return -ENOMEM;
++
++	t = ns2usecs(mp->timestamp);
++	usecs = do_div(t, USEC_PER_SEC);
++	secs = (unsigned long) t;
++	r = snprintf(buf, strmaxlen,
++	    "%d %d %ld (%ld) %s <- %d %d %s %lu.%06lu\n", mp->pid,
++	    MAX_RT_PRIO-1 - mp->prio, mp->latency, mp->timeroffset, mp->comm,
++	    mp->current_pid, MAX_RT_PRIO-1 - mp->current_prio, mp->current_comm,
++	    secs, usecs);
++	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
++	kfree(buf);
++	return r;
++}
++#endif
++
++static ssize_t
++show_enable(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos)
++{
++	char buf[64];
++	struct enable_data *ed = file->private_data;
++	int r;
++
++	r = snprintf(buf, sizeof(buf), "%d\n", ed->enabled);
++	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
++}
++
++static ssize_t
++do_enable(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos)
++{
++	char buf[64];
++	long enable;
++	struct enable_data *ed = file->private_data;
++
++	if (cnt >= sizeof(buf))
++		return -EINVAL;
++
++	if (copy_from_user(&buf, ubuf, cnt))
++		return -EFAULT;
++
++	buf[cnt] = 0;
++
++	if (kstrtoul(buf, 10, &enable))
++		return -EINVAL;
++
++	if ((enable && ed->enabled) || (!enable && !ed->enabled))
++		return cnt;
++
++	if (enable) {
++		int ret;
++
++		switch (ed->latency_type) {
++#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
++		case PREEMPTIRQSOFF_LATENCY:
++			ret = register_trace_preemptirqsoff_hist(
++			    probe_preemptirqsoff_hist, NULL);
++			if (ret) {
++				pr_info("wakeup trace: Couldn't assign "
++				    "probe_preemptirqsoff_hist "
++				    "to trace_preemptirqsoff_hist\n");
++				return ret;
++			}
++			break;
++#endif
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++		case WAKEUP_LATENCY:
++			ret = register_trace_sched_wakeup(
++			    probe_wakeup_latency_hist_start, NULL);
++			if (ret) {
++				pr_info("wakeup trace: Couldn't assign "
++				    "probe_wakeup_latency_hist_start "
++				    "to trace_sched_wakeup\n");
++				return ret;
++			}
++			ret = register_trace_sched_wakeup_new(
++			    probe_wakeup_latency_hist_start, NULL);
++			if (ret) {
++				pr_info("wakeup trace: Couldn't assign "
++				    "probe_wakeup_latency_hist_start "
++				    "to trace_sched_wakeup_new\n");
++				unregister_trace_sched_wakeup(
++				    probe_wakeup_latency_hist_start, NULL);
++				return ret;
++			}
++			ret = register_trace_sched_switch(
++			    probe_wakeup_latency_hist_stop, NULL);
++			if (ret) {
++				pr_info("wakeup trace: Couldn't assign "
++				    "probe_wakeup_latency_hist_stop "
++				    "to trace_sched_switch\n");
++				unregister_trace_sched_wakeup(
++				    probe_wakeup_latency_hist_start, NULL);
++				unregister_trace_sched_wakeup_new(
++				    probe_wakeup_latency_hist_start, NULL);
++				return ret;
++			}
++			ret = register_trace_sched_migrate_task(
++			    probe_sched_migrate_task, NULL);
++			if (ret) {
++				pr_info("wakeup trace: Couldn't assign "
++				    "probe_sched_migrate_task "
++				    "to trace_sched_migrate_task\n");
++				unregister_trace_sched_wakeup(
++				    probe_wakeup_latency_hist_start, NULL);
++				unregister_trace_sched_wakeup_new(
++				    probe_wakeup_latency_hist_start, NULL);
++				unregister_trace_sched_switch(
++				    probe_wakeup_latency_hist_stop, NULL);
++				return ret;
++			}
++			break;
++#endif
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++		case MISSED_TIMER_OFFSETS:
++			ret = register_trace_hrtimer_interrupt(
++			    probe_hrtimer_interrupt, NULL);
++			if (ret) {
++				pr_info("wakeup trace: Couldn't assign "
++				    "probe_hrtimer_interrupt "
++				    "to trace_hrtimer_interrupt\n");
++				return ret;
++			}
++			break;
++#endif
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++		case TIMERANDWAKEUP_LATENCY:
++			if (!wakeup_latency_enabled_data.enabled ||
++			    !missed_timer_offsets_enabled_data.enabled)
++				return -EINVAL;
++			break;
++#endif
++		default:
++			break;
++		}
++	} else {
++		switch (ed->latency_type) {
++#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
++		case PREEMPTIRQSOFF_LATENCY:
++			{
++				int cpu;
++
++				unregister_trace_preemptirqsoff_hist(
++				    probe_preemptirqsoff_hist, NULL);
++				for_each_online_cpu(cpu) {
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++					per_cpu(hist_irqsoff_counting,
++					    cpu) = 0;
++#endif
++#ifdef CONFIG_PREEMPT_OFF_HIST
++					per_cpu(hist_preemptoff_counting,
++					    cpu) = 0;
++#endif
++#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
++					per_cpu(hist_preemptirqsoff_counting,
++					    cpu) = 0;
++#endif
++				}
++			}
++			break;
++#endif
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++		case WAKEUP_LATENCY:
++			{
++				int cpu;
++
++				unregister_trace_sched_wakeup(
++				    probe_wakeup_latency_hist_start, NULL);
++				unregister_trace_sched_wakeup_new(
++				    probe_wakeup_latency_hist_start, NULL);
++				unregister_trace_sched_switch(
++				    probe_wakeup_latency_hist_stop, NULL);
++				unregister_trace_sched_migrate_task(
++				    probe_sched_migrate_task, NULL);
++
++				for_each_online_cpu(cpu) {
++					per_cpu(wakeup_task, cpu) = NULL;
++					per_cpu(wakeup_sharedprio, cpu) = 0;
++				}
++			}
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++			timerandwakeup_enabled_data.enabled = 0;
++#endif
++			break;
++#endif
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++		case MISSED_TIMER_OFFSETS:
++			unregister_trace_hrtimer_interrupt(
++			    probe_hrtimer_interrupt, NULL);
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++			timerandwakeup_enabled_data.enabled = 0;
++#endif
++			break;
++#endif
++		default:
++			break;
++		}
++	}
++	ed->enabled = enable;
++	return cnt;
++}
++
++static const struct file_operations latency_hist_reset_fops = {
++	.open = tracing_open_generic,
++	.write = latency_hist_reset,
++};
++
++static const struct file_operations enable_fops = {
++	.open = tracing_open_generic,
++	.read = show_enable,
++	.write = do_enable,
++};
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++static const struct file_operations pid_fops = {
++	.open = tracing_open_generic,
++	.read = show_pid,
++	.write = do_pid,
++};
++
++static const struct file_operations maxlatproc_fops = {
++	.open = tracing_open_generic,
++	.read = show_maxlatproc,
++};
++#endif
++
++#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
++static notrace void probe_preemptirqsoff_hist(void *v, int reason,
++	int starthist)
++{
++	int cpu = raw_smp_processor_id();
++	int time_set = 0;
++
++	if (starthist) {
++		cycle_t uninitialized_var(start);
++
++		if (!preempt_count() && !irqs_disabled())
++			return;
++
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++		if ((reason == IRQS_OFF || reason == TRACE_START) &&
++		    !per_cpu(hist_irqsoff_counting, cpu)) {
++			per_cpu(hist_irqsoff_counting, cpu) = 1;
++			start = ftrace_now(cpu);
++			time_set++;
++			per_cpu(hist_irqsoff_start, cpu) = start;
++		}
++#endif
++
++#ifdef CONFIG_PREEMPT_OFF_HIST
++		if ((reason == PREEMPT_OFF || reason == TRACE_START) &&
++		    !per_cpu(hist_preemptoff_counting, cpu)) {
++			per_cpu(hist_preemptoff_counting, cpu) = 1;
++			if (!(time_set++))
++				start = ftrace_now(cpu);
++			per_cpu(hist_preemptoff_start, cpu) = start;
++		}
++#endif
++
++#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
++		if (per_cpu(hist_irqsoff_counting, cpu) &&
++		    per_cpu(hist_preemptoff_counting, cpu) &&
++		    !per_cpu(hist_preemptirqsoff_counting, cpu)) {
++			per_cpu(hist_preemptirqsoff_counting, cpu) = 1;
++			if (!time_set)
++				start = ftrace_now(cpu);
++			per_cpu(hist_preemptirqsoff_start, cpu) = start;
++		}
++#endif
++	} else {
++		cycle_t uninitialized_var(stop);
++
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++		if ((reason == IRQS_ON || reason == TRACE_STOP) &&
++		    per_cpu(hist_irqsoff_counting, cpu)) {
++			cycle_t start = per_cpu(hist_irqsoff_start, cpu);
++
++			stop = ftrace_now(cpu);
++			time_set++;
++			if (start) {
++				long latency = ((long) (stop - start)) /
++				    NSECS_PER_USECS;
++
++				latency_hist(IRQSOFF_LATENCY, cpu, latency, 0,
++				    stop, NULL);
++			}
++			per_cpu(hist_irqsoff_counting, cpu) = 0;
++		}
++#endif
++
++#ifdef CONFIG_PREEMPT_OFF_HIST
++		if ((reason == PREEMPT_ON || reason == TRACE_STOP) &&
++		    per_cpu(hist_preemptoff_counting, cpu)) {
++			cycle_t start = per_cpu(hist_preemptoff_start, cpu);
++
++			if (!(time_set++))
++				stop = ftrace_now(cpu);
++			if (start) {
++				long latency = ((long) (stop - start)) /
++				    NSECS_PER_USECS;
++
++				latency_hist(PREEMPTOFF_LATENCY, cpu, latency,
++				    0, stop, NULL);
++			}
++			per_cpu(hist_preemptoff_counting, cpu) = 0;
++		}
++#endif
++
++#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
++		if ((!per_cpu(hist_irqsoff_counting, cpu) ||
++		     !per_cpu(hist_preemptoff_counting, cpu)) &&
++		   per_cpu(hist_preemptirqsoff_counting, cpu)) {
++			cycle_t start = per_cpu(hist_preemptirqsoff_start, cpu);
++
++			if (!time_set)
++				stop = ftrace_now(cpu);
++			if (start) {
++				long latency = ((long) (stop - start)) /
++				    NSECS_PER_USECS;
++
++				latency_hist(PREEMPTIRQSOFF_LATENCY, cpu,
++				    latency, 0, stop, NULL);
++			}
++			per_cpu(hist_preemptirqsoff_counting, cpu) = 0;
++		}
++#endif
++	}
++}
++#endif
++
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++static DEFINE_RAW_SPINLOCK(wakeup_lock);
++static notrace void probe_sched_migrate_task(void *v, struct task_struct *task,
++	int cpu)
++{
++	int old_cpu = task_cpu(task);
++
++	if (cpu != old_cpu) {
++		unsigned long flags;
++		struct task_struct *cpu_wakeup_task;
++
++		raw_spin_lock_irqsave(&wakeup_lock, flags);
++
++		cpu_wakeup_task = per_cpu(wakeup_task, old_cpu);
++		if (task == cpu_wakeup_task) {
++			put_task_struct(cpu_wakeup_task);
++			per_cpu(wakeup_task, old_cpu) = NULL;
++			cpu_wakeup_task = per_cpu(wakeup_task, cpu) = task;
++			get_task_struct(cpu_wakeup_task);
++		}
++
++		raw_spin_unlock_irqrestore(&wakeup_lock, flags);
++	}
++}
++
++static notrace void probe_wakeup_latency_hist_start(void *v,
++	struct task_struct *p, int success)
++{
++	unsigned long flags;
++	struct task_struct *curr = current;
++	int cpu = task_cpu(p);
++	struct task_struct *cpu_wakeup_task;
++
++	raw_spin_lock_irqsave(&wakeup_lock, flags);
++
++	cpu_wakeup_task = per_cpu(wakeup_task, cpu);
++
++	if (wakeup_pid) {
++		if ((cpu_wakeup_task && p->prio == cpu_wakeup_task->prio) ||
++		    p->prio == curr->prio)
++			per_cpu(wakeup_sharedprio, cpu) = 1;
++		if (likely(wakeup_pid != task_pid_nr(p)))
++			goto out;
++	} else {
++		if (likely(!rt_task(p)) ||
++		    (cpu_wakeup_task && p->prio > cpu_wakeup_task->prio) ||
++		    p->prio > curr->prio)
++			goto out;
++		if ((cpu_wakeup_task && p->prio == cpu_wakeup_task->prio) ||
++		    p->prio == curr->prio)
++			per_cpu(wakeup_sharedprio, cpu) = 1;
++	}
++
++	if (cpu_wakeup_task)
++		put_task_struct(cpu_wakeup_task);
++	cpu_wakeup_task = per_cpu(wakeup_task, cpu) = p;
++	get_task_struct(cpu_wakeup_task);
++	cpu_wakeup_task->preempt_timestamp_hist =
++		ftrace_now(raw_smp_processor_id());
++out:
++	raw_spin_unlock_irqrestore(&wakeup_lock, flags);
++}
++
++static notrace void probe_wakeup_latency_hist_stop(void *v,
++	struct task_struct *prev, struct task_struct *next)
++{
++	unsigned long flags;
++	int cpu = task_cpu(next);
++	long latency;
++	cycle_t stop;
++	struct task_struct *cpu_wakeup_task;
++
++	raw_spin_lock_irqsave(&wakeup_lock, flags);
++
++	cpu_wakeup_task = per_cpu(wakeup_task, cpu);
++
++	if (cpu_wakeup_task == NULL)
++		goto out;
++
++	/* Already running? */
++	if (unlikely(current == cpu_wakeup_task))
++		goto out_reset;
++
++	if (next != cpu_wakeup_task) {
++		if (next->prio < cpu_wakeup_task->prio)
++			goto out_reset;
++
++		if (next->prio == cpu_wakeup_task->prio)
++			per_cpu(wakeup_sharedprio, cpu) = 1;
++
++		goto out;
++	}
++
++	if (current->prio == cpu_wakeup_task->prio)
++		per_cpu(wakeup_sharedprio, cpu) = 1;
++
++	/*
++	 * The task we are waiting for is about to be switched to.
++	 * Calculate latency and store it in histogram.
++	 */
++	stop = ftrace_now(raw_smp_processor_id());
++
++	latency = ((long) (stop - next->preempt_timestamp_hist)) /
++	    NSECS_PER_USECS;
++
++	if (per_cpu(wakeup_sharedprio, cpu)) {
++		latency_hist(WAKEUP_LATENCY_SHAREDPRIO, cpu, latency, 0, stop,
++		    next);
++		per_cpu(wakeup_sharedprio, cpu) = 0;
++	} else {
++		latency_hist(WAKEUP_LATENCY, cpu, latency, 0, stop, next);
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++		if (timerandwakeup_enabled_data.enabled) {
++			latency_hist(TIMERANDWAKEUP_LATENCY, cpu,
++			    next->timer_offset + latency, next->timer_offset,
++			    stop, next);
++		}
++#endif
++	}
++
++out_reset:
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++	next->timer_offset = 0;
++#endif
++	put_task_struct(cpu_wakeup_task);
++	per_cpu(wakeup_task, cpu) = NULL;
++out:
++	raw_spin_unlock_irqrestore(&wakeup_lock, flags);
++}
++#endif
++
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++static notrace void probe_hrtimer_interrupt(void *v, int cpu,
++	long long latency_ns, struct task_struct *curr,
++	struct task_struct *task)
++{
++	if (latency_ns <= 0 && task != NULL && rt_task(task) &&
++	    (task->prio < curr->prio ||
++	    (task->prio == curr->prio &&
++	    !cpumask_test_cpu(cpu, &task->cpus_allowed)))) {
++		long latency;
++		cycle_t now;
++
++		if (missed_timer_offsets_pid) {
++			if (likely(missed_timer_offsets_pid !=
++			    task_pid_nr(task)))
++				return;
++		}
++
++		now = ftrace_now(cpu);
++		latency = (long) div_s64(-latency_ns, NSECS_PER_USECS);
++		latency_hist(MISSED_TIMER_OFFSETS, cpu, latency, latency, now,
++		    task);
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++		task->timer_offset = latency;
++#endif
++	}
++}
++#endif
++
++static __init int latency_hist_init(void)
++{
++	struct dentry *latency_hist_root = NULL;
++	struct dentry *dentry;
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++	struct dentry *dentry_sharedprio;
++#endif
++	struct dentry *entry;
++	struct dentry *enable_root;
++	int i = 0;
++	struct hist_data *my_hist;
++	char name[64];
++	char *cpufmt = "CPU%d";
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++	char *cpufmt_maxlatproc = "max_latency-CPU%d";
++	struct maxlatproc_data *mp = NULL;
++#endif
++
++	dentry = tracing_init_dentry();
++	latency_hist_root = debugfs_create_dir(latency_hist_dir_root, dentry);
++	enable_root = debugfs_create_dir("enable", latency_hist_root);
++
++#ifdef CONFIG_INTERRUPT_OFF_HIST
++	dentry = debugfs_create_dir(irqsoff_hist_dir, latency_hist_root);
++	for_each_possible_cpu(i) {
++		sprintf(name, cpufmt, i);
++		entry = debugfs_create_file(name, 0444, dentry,
++		    &per_cpu(irqsoff_hist, i), &latency_hist_fops);
++		my_hist = &per_cpu(irqsoff_hist, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++	}
++	entry = debugfs_create_file("reset", 0644, dentry,
++	    (void *)IRQSOFF_LATENCY, &latency_hist_reset_fops);
++#endif
++
++#ifdef CONFIG_PREEMPT_OFF_HIST
++	dentry = debugfs_create_dir(preemptoff_hist_dir,
++	    latency_hist_root);
++	for_each_possible_cpu(i) {
++		sprintf(name, cpufmt, i);
++		entry = debugfs_create_file(name, 0444, dentry,
++		    &per_cpu(preemptoff_hist, i), &latency_hist_fops);
++		my_hist = &per_cpu(preemptoff_hist, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++	}
++	entry = debugfs_create_file("reset", 0644, dentry,
++	    (void *)PREEMPTOFF_LATENCY, &latency_hist_reset_fops);
++#endif
++
++#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
++	dentry = debugfs_create_dir(preemptirqsoff_hist_dir,
++	    latency_hist_root);
++	for_each_possible_cpu(i) {
++		sprintf(name, cpufmt, i);
++		entry = debugfs_create_file(name, 0444, dentry,
++		    &per_cpu(preemptirqsoff_hist, i), &latency_hist_fops);
++		my_hist = &per_cpu(preemptirqsoff_hist, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++	}
++	entry = debugfs_create_file("reset", 0644, dentry,
++	    (void *)PREEMPTIRQSOFF_LATENCY, &latency_hist_reset_fops);
++#endif
++
++#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
++	entry = debugfs_create_file("preemptirqsoff", 0644,
++	    enable_root, (void *)&preemptirqsoff_enabled_data,
++	    &enable_fops);
++#endif
++
++#ifdef CONFIG_WAKEUP_LATENCY_HIST
++	dentry = debugfs_create_dir(wakeup_latency_hist_dir,
++	    latency_hist_root);
++	dentry_sharedprio = debugfs_create_dir(
++	    wakeup_latency_hist_dir_sharedprio, dentry);
++	for_each_possible_cpu(i) {
++		sprintf(name, cpufmt, i);
++
++		entry = debugfs_create_file(name, 0444, dentry,
++		    &per_cpu(wakeup_latency_hist, i),
++		    &latency_hist_fops);
++		my_hist = &per_cpu(wakeup_latency_hist, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++
++		entry = debugfs_create_file(name, 0444, dentry_sharedprio,
++		    &per_cpu(wakeup_latency_hist_sharedprio, i),
++		    &latency_hist_fops);
++		my_hist = &per_cpu(wakeup_latency_hist_sharedprio, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++
++		sprintf(name, cpufmt_maxlatproc, i);
++
++		mp = &per_cpu(wakeup_maxlatproc, i);
++		entry = debugfs_create_file(name, 0444, dentry, mp,
++		    &maxlatproc_fops);
++		clear_maxlatprocdata(mp);
++
++		mp = &per_cpu(wakeup_maxlatproc_sharedprio, i);
++		entry = debugfs_create_file(name, 0444, dentry_sharedprio, mp,
++		    &maxlatproc_fops);
++		clear_maxlatprocdata(mp);
++	}
++	entry = debugfs_create_file("pid", 0644, dentry,
++	    (void *)&wakeup_pid, &pid_fops);
++	entry = debugfs_create_file("reset", 0644, dentry,
++	    (void *)WAKEUP_LATENCY, &latency_hist_reset_fops);
++	entry = debugfs_create_file("reset", 0644, dentry_sharedprio,
++	    (void *)WAKEUP_LATENCY_SHAREDPRIO, &latency_hist_reset_fops);
++	entry = debugfs_create_file("wakeup", 0644,
++	    enable_root, (void *)&wakeup_latency_enabled_data,
++	    &enable_fops);
++#endif
++
++#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
++	dentry = debugfs_create_dir(missed_timer_offsets_dir,
++	    latency_hist_root);
++	for_each_possible_cpu(i) {
++		sprintf(name, cpufmt, i);
++		entry = debugfs_create_file(name, 0444, dentry,
++		    &per_cpu(missed_timer_offsets, i), &latency_hist_fops);
++		my_hist = &per_cpu(missed_timer_offsets, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++
++		sprintf(name, cpufmt_maxlatproc, i);
++		mp = &per_cpu(missed_timer_offsets_maxlatproc, i);
++		entry = debugfs_create_file(name, 0444, dentry, mp,
++		    &maxlatproc_fops);
++		clear_maxlatprocdata(mp);
++	}
++	entry = debugfs_create_file("pid", 0644, dentry,
++	    (void *)&missed_timer_offsets_pid, &pid_fops);
++	entry = debugfs_create_file("reset", 0644, dentry,
++	    (void *)MISSED_TIMER_OFFSETS, &latency_hist_reset_fops);
++	entry = debugfs_create_file("missed_timer_offsets", 0644,
++	    enable_root, (void *)&missed_timer_offsets_enabled_data,
++	    &enable_fops);
++#endif
++
++#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
++	defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
++	dentry = debugfs_create_dir(timerandwakeup_latency_hist_dir,
++	    latency_hist_root);
++	for_each_possible_cpu(i) {
++		sprintf(name, cpufmt, i);
++		entry = debugfs_create_file(name, 0444, dentry,
++		    &per_cpu(timerandwakeup_latency_hist, i),
++		    &latency_hist_fops);
++		my_hist = &per_cpu(timerandwakeup_latency_hist, i);
++		atomic_set(&my_hist->hist_mode, 1);
++		my_hist->min_lat = LONG_MAX;
++
++		sprintf(name, cpufmt_maxlatproc, i);
++		mp = &per_cpu(timerandwakeup_maxlatproc, i);
++		entry = debugfs_create_file(name, 0444, dentry, mp,
++		    &maxlatproc_fops);
++		clear_maxlatprocdata(mp);
++	}
++	entry = debugfs_create_file("reset", 0644, dentry,
++	    (void *)TIMERANDWAKEUP_LATENCY, &latency_hist_reset_fops);
++	entry = debugfs_create_file("timerandwakeup", 0644,
++	    enable_root, (void *)&timerandwakeup_enabled_data,
++	    &enable_fops);
++#endif
++	return 0;
++}
++
++device_initcall(latency_hist_init);
+diff -Nur linux-3.18.8.orig/kernel/trace/Makefile linux-3.18.8/kernel/trace/Makefile
+--- linux-3.18.8.orig/kernel/trace/Makefile	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/Makefile	2015-03-03 08:05:18.000000000 +0100
+@@ -36,6 +36,10 @@
+ obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
+ obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
+ obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
++obj-$(CONFIG_INTERRUPT_OFF_HIST) += latency_hist.o
++obj-$(CONFIG_PREEMPT_OFF_HIST) += latency_hist.o
++obj-$(CONFIG_WAKEUP_LATENCY_HIST) += latency_hist.o
++obj-$(CONFIG_MISSED_TIMER_OFFSETS_HIST) += latency_hist.o
+ obj-$(CONFIG_NOP_TRACER) += trace_nop.o
+ obj-$(CONFIG_STACK_TRACER) += trace_stack.o
+ obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
+diff -Nur linux-3.18.8.orig/kernel/trace/trace.c linux-3.18.8/kernel/trace/trace.c
+--- linux-3.18.8.orig/kernel/trace/trace.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/trace.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1579,6 +1579,7 @@
+ 	struct task_struct *tsk = current;
+ 
+ 	entry->preempt_count		= pc & 0xff;
++	entry->preempt_lazy_count	= preempt_lazy_count();
+ 	entry->pid			= (tsk) ? tsk->pid : 0;
+ 	entry->flags =
+ #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+@@ -1588,8 +1589,11 @@
+ #endif
+ 		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
+ 		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
+-		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
++		(tif_need_resched_now() ? TRACE_FLAG_NEED_RESCHED : 0) |
++		(need_resched_lazy() ? TRACE_FLAG_NEED_RESCHED_LAZY : 0) |
+ 		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
++
++	entry->migrate_disable = (tsk) ? __migrate_disabled(tsk) & 0xFF : 0;
+ }
+ EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
+ 
+@@ -2509,14 +2513,17 @@
+ 
+ static void print_lat_help_header(struct seq_file *m)
+ {
+-	seq_puts(m, "#                  _------=> CPU#            \n");
+-	seq_puts(m, "#                 / _-----=> irqs-off        \n");
+-	seq_puts(m, "#                | / _----=> need-resched    \n");
+-	seq_puts(m, "#                || / _---=> hardirq/softirq \n");
+-	seq_puts(m, "#                ||| / _--=> preempt-depth   \n");
+-	seq_puts(m, "#                |||| /     delay             \n");
+-	seq_puts(m, "#  cmd     pid   ||||| time  |   caller      \n");
+-	seq_puts(m, "#     \\   /      |||||  \\    |   /           \n");
++	seq_puts(m, "#                   _--------=> CPU#              \n");
++	seq_puts(m, "#                  / _-------=> irqs-off          \n");
++	seq_puts(m, "#                 | / _------=> need-resched      \n");
++	seq_puts(m, "#                 || / _-----=> need-resched_lazy \n");
++	seq_puts(m, "#                 ||| / _----=> hardirq/softirq   \n");
++	seq_puts(m, "#                 |||| / _---=> preempt-depth     \n");
++	seq_puts(m, "#                 ||||| / _--=> preempt-lazy-depth\n");
++	seq_puts(m, "#                 |||||| / _-=> migrate-disable   \n");
++	seq_puts(m, "#                 ||||||| /     delay             \n");
++	seq_puts(m, "#  cmd     pid    |||||||| time  |   caller       \n");
++	seq_puts(m, "#     \\   /      ||||||||  \\   |   /            \n");
+ }
+ 
+ static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
+@@ -2540,13 +2547,16 @@
+ static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
+ {
+ 	print_event_info(buf, m);
+-	seq_puts(m, "#                              _-----=> irqs-off\n");
+-	seq_puts(m, "#                             / _----=> need-resched\n");
+-	seq_puts(m, "#                            | / _---=> hardirq/softirq\n");
+-	seq_puts(m, "#                            || / _--=> preempt-depth\n");
+-	seq_puts(m, "#                            ||| /     delay\n");
+-	seq_puts(m, "#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION\n");
+-	seq_puts(m, "#              | |       |   ||||       |         |\n");
++	seq_puts(m, "#                              _-------=> irqs-off          \n");
++	seq_puts(m, "#                            /  _------=> need-resched      \n");
++	seq_puts(m, "#                            |/  _-----=> need-resched_lazy \n");
++	seq_puts(m, "#                            ||/  _----=> hardirq/softirq   \n");
++	seq_puts(m, "#                            |||/  _---=> preempt-depth     \n");
++	seq_puts(m, "#                            ||||/  _--=> preempt-lazy-depth\n");
++	seq_puts(m, "#                            ||||| / _-=> migrate-disable   \n");
++	seq_puts(m, "#                            |||||| /     delay\n");
++	seq_puts(m, "#           TASK-PID   CPU#  ||||||  TIMESTAMP  FUNCTION\n");
++	seq_puts(m, "#              | |       |   ||||||     |         |\n");
+ }
+ 
+ void
+diff -Nur linux-3.18.8.orig/kernel/trace/trace_events.c linux-3.18.8/kernel/trace/trace_events.c
+--- linux-3.18.8.orig/kernel/trace/trace_events.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/trace_events.c	2015-03-03 08:05:18.000000000 +0100
+@@ -162,6 +162,8 @@
+ 	__common_field(unsigned char, flags);
+ 	__common_field(unsigned char, preempt_count);
+ 	__common_field(int, pid);
++	__common_field(unsigned short, migrate_disable);
++	__common_field(unsigned short, padding);
+ 
+ 	return ret;
+ }
+diff -Nur linux-3.18.8.orig/kernel/trace/trace.h linux-3.18.8/kernel/trace/trace.h
+--- linux-3.18.8.orig/kernel/trace/trace.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/trace.h	2015-03-03 08:05:18.000000000 +0100
+@@ -119,6 +119,7 @@
+  *  NEED_RESCHED	- reschedule is requested
+  *  HARDIRQ		- inside an interrupt handler
+  *  SOFTIRQ		- inside a softirq handler
++ *  NEED_RESCHED_LAZY	- lazy reschedule is requested
+  */
+ enum trace_flag_type {
+ 	TRACE_FLAG_IRQS_OFF		= 0x01,
+@@ -127,6 +128,7 @@
+ 	TRACE_FLAG_HARDIRQ		= 0x08,
+ 	TRACE_FLAG_SOFTIRQ		= 0x10,
+ 	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,
++	TRACE_FLAG_NEED_RESCHED_LAZY    = 0x40,
+ };
+ 
+ #define TRACE_BUF_SIZE		1024
+diff -Nur linux-3.18.8.orig/kernel/trace/trace_irqsoff.c linux-3.18.8/kernel/trace/trace_irqsoff.c
+--- linux-3.18.8.orig/kernel/trace/trace_irqsoff.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/trace_irqsoff.c	2015-03-03 08:05:18.000000000 +0100
+@@ -17,6 +17,7 @@
+ #include <linux/fs.h>
+ 
+ #include "trace.h"
++#include <trace/events/hist.h>
+ 
+ static struct trace_array		*irqsoff_trace __read_mostly;
+ static int				tracer_enabled __read_mostly;
+@@ -435,11 +436,13 @@
+ {
+ 	if (preempt_trace() || irq_trace())
+ 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
++	trace_preemptirqsoff_hist(TRACE_START, 1);
+ }
+ EXPORT_SYMBOL_GPL(start_critical_timings);
+ 
+ void stop_critical_timings(void)
+ {
++	trace_preemptirqsoff_hist(TRACE_STOP, 0);
+ 	if (preempt_trace() || irq_trace())
+ 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+ }
+@@ -449,6 +452,7 @@
+ #ifdef CONFIG_PROVE_LOCKING
+ void time_hardirqs_on(unsigned long a0, unsigned long a1)
+ {
++	trace_preemptirqsoff_hist(IRQS_ON, 0);
+ 	if (!preempt_trace() && irq_trace())
+ 		stop_critical_timing(a0, a1);
+ }
+@@ -457,6 +461,7 @@
+ {
+ 	if (!preempt_trace() && irq_trace())
+ 		start_critical_timing(a0, a1);
++	trace_preemptirqsoff_hist(IRQS_OFF, 1);
+ }
+ 
+ #else /* !CONFIG_PROVE_LOCKING */
+@@ -482,6 +487,7 @@
+  */
+ void trace_hardirqs_on(void)
+ {
++	trace_preemptirqsoff_hist(IRQS_ON, 0);
+ 	if (!preempt_trace() && irq_trace())
+ 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+ }
+@@ -491,11 +497,13 @@
+ {
+ 	if (!preempt_trace() && irq_trace())
+ 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
++	trace_preemptirqsoff_hist(IRQS_OFF, 1);
+ }
+ EXPORT_SYMBOL(trace_hardirqs_off);
+ 
+ __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+ {
++	trace_preemptirqsoff_hist(IRQS_ON, 0);
+ 	if (!preempt_trace() && irq_trace())
+ 		stop_critical_timing(CALLER_ADDR0, caller_addr);
+ }
+@@ -505,6 +513,7 @@
+ {
+ 	if (!preempt_trace() && irq_trace())
+ 		start_critical_timing(CALLER_ADDR0, caller_addr);
++	trace_preemptirqsoff_hist(IRQS_OFF, 1);
+ }
+ EXPORT_SYMBOL(trace_hardirqs_off_caller);
+ 
+@@ -514,12 +523,14 @@
+ #ifdef CONFIG_PREEMPT_TRACER
+ void trace_preempt_on(unsigned long a0, unsigned long a1)
+ {
++	trace_preemptirqsoff_hist(PREEMPT_ON, 0);
+ 	if (preempt_trace() && !irq_trace())
+ 		stop_critical_timing(a0, a1);
+ }
+ 
+ void trace_preempt_off(unsigned long a0, unsigned long a1)
+ {
++	trace_preemptirqsoff_hist(PREEMPT_ON, 1);
+ 	if (preempt_trace() && !irq_trace())
+ 		start_critical_timing(a0, a1);
+ }
+diff -Nur linux-3.18.8.orig/kernel/trace/trace_output.c linux-3.18.8/kernel/trace/trace_output.c
+--- linux-3.18.8.orig/kernel/trace/trace_output.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/trace/trace_output.c	2015-03-03 08:05:18.000000000 +0100
+@@ -410,6 +410,7 @@
+ {
+ 	char hardsoft_irq;
+ 	char need_resched;
++	char need_resched_lazy;
+ 	char irqs_off;
+ 	int hardirq;
+ 	int softirq;
+@@ -438,6 +439,8 @@
+ 		need_resched = '.';
+ 		break;
+ 	}
++	need_resched_lazy =
++		(entry->flags & TRACE_FLAG_NEED_RESCHED_LAZY) ? 'L' : '.';
+ 
+ 	hardsoft_irq =
+ 		(hardirq && softirq) ? 'H' :
+@@ -445,8 +448,9 @@
+ 		softirq ? 's' :
+ 		'.';
+ 
+-	if (!trace_seq_printf(s, "%c%c%c",
+-			      irqs_off, need_resched, hardsoft_irq))
++	if (!trace_seq_printf(s, "%c%c%c%c",
++			      irqs_off, need_resched, need_resched_lazy,
++			      hardsoft_irq))
+ 		return 0;
+ 
+ 	if (entry->preempt_count)
+@@ -454,6 +458,16 @@
+ 	else
+ 		ret = trace_seq_putc(s, '.');
+ 
++	if (entry->preempt_lazy_count)
++		ret = trace_seq_printf(s, "%x", entry->preempt_lazy_count);
++	else
++		ret = trace_seq_putc(s, '.');
++
++	if (entry->migrate_disable)
++		ret = trace_seq_printf(s, "%x", entry->migrate_disable);
++	else
++		ret = trace_seq_putc(s, '.');
++
+ 	return ret;
+ }
+ 
+diff -Nur linux-3.18.8.orig/kernel/user.c linux-3.18.8/kernel/user.c
+--- linux-3.18.8.orig/kernel/user.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/user.c	2015-03-03 08:05:18.000000000 +0100
+@@ -158,11 +158,11 @@
+ 	if (!up)
+ 		return;
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 	if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
+ 		free_user(up, flags);
+ 	else
+-		local_irq_restore(flags);
++		local_irq_restore_nort(flags);
+ }
+ 
+ struct user_struct *alloc_uid(kuid_t uid)
+diff -Nur linux-3.18.8.orig/kernel/watchdog.c linux-3.18.8/kernel/watchdog.c
+--- linux-3.18.8.orig/kernel/watchdog.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/watchdog.c	2015-03-03 08:05:18.000000000 +0100
+@@ -248,6 +248,8 @@
+ 
+ #ifdef CONFIG_HARDLOCKUP_DETECTOR
+ 
++static DEFINE_RAW_SPINLOCK(watchdog_output_lock);
++
+ static struct perf_event_attr wd_hw_attr = {
+ 	.type		= PERF_TYPE_HARDWARE,
+ 	.config		= PERF_COUNT_HW_CPU_CYCLES,
+@@ -281,13 +283,21 @@
+ 		/* only print hardlockups once */
+ 		if (__this_cpu_read(hard_watchdog_warn) == true)
+ 			return;
++		/*
++		 * If early-printk is enabled then make sure we do not
++		 * lock up in printk() and kill console logging:
++		 */
++		printk_kill();
+ 
+-		if (hardlockup_panic)
++		if (hardlockup_panic) {
+ 			panic("Watchdog detected hard LOCKUP on cpu %d",
+ 			      this_cpu);
+-		else
++		} else {
++			raw_spin_lock(&watchdog_output_lock);
+ 			WARN(1, "Watchdog detected hard LOCKUP on cpu %d",
+ 			     this_cpu);
++			raw_spin_unlock(&watchdog_output_lock);
++		}
+ 
+ 		__this_cpu_write(hard_watchdog_warn, true);
+ 		return;
+@@ -430,6 +440,7 @@
+ 	/* kick off the timer for the hardlockup detector */
+ 	hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ 	hrtimer->function = watchdog_timer_fn;
++	hrtimer->irqsafe = 1;
+ 
+ 	/* Enable the perf event */
+ 	watchdog_nmi_enable(cpu);
+diff -Nur linux-3.18.8.orig/kernel/workqueue.c linux-3.18.8/kernel/workqueue.c
+--- linux-3.18.8.orig/kernel/workqueue.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/workqueue.c	2015-03-03 08:05:18.000000000 +0100
+@@ -48,6 +48,8 @@
+ #include <linux/nodemask.h>
+ #include <linux/moduleparam.h>
+ #include <linux/uaccess.h>
++#include <linux/locallock.h>
++#include <linux/delay.h>
+ 
+ #include "workqueue_internal.h"
+ 
+@@ -121,15 +123,20 @@
+  *    cpu or grabbing pool->lock is enough for read access.  If
+  *    POOL_DISASSOCIATED is set, it's identical to L.
+  *
++ *    On RT we need the extra protection via rt_lock_idle_list() for
++ *    the list manipulations against read access from
++ *    wq_worker_sleeping(). All other places are nicely serialized via
++ *    pool->lock.
++ *
+  * A: pool->attach_mutex protected.
+  *
+  * PL: wq_pool_mutex protected.
+  *
+- * PR: wq_pool_mutex protected for writes.  Sched-RCU protected for reads.
++ * PR: wq_pool_mutex protected for writes.  RCU protected for reads.
+  *
+  * WQ: wq->mutex protected.
+  *
+- * WR: wq->mutex protected for writes.  Sched-RCU protected for reads.
++ * WR: wq->mutex protected for writes.  RCU protected for reads.
+  *
+  * MD: wq_mayday_lock protected.
+  */
+@@ -177,7 +184,7 @@
+ 	atomic_t		nr_running ____cacheline_aligned_in_smp;
+ 
+ 	/*
+-	 * Destruction of pool is sched-RCU protected to allow dereferences
++	 * Destruction of pool is RCU protected to allow dereferences
+ 	 * from get_work_pool().
+ 	 */
+ 	struct rcu_head		rcu;
+@@ -206,7 +213,7 @@
+ 	/*
+ 	 * Release of unbound pwq is punted to system_wq.  See put_pwq()
+ 	 * and pwq_unbound_release_workfn() for details.  pool_workqueue
+-	 * itself is also sched-RCU protected so that the first pwq can be
++	 * itself is also RCU protected so that the first pwq can be
+ 	 * determined without grabbing wq->mutex.
+ 	 */
+ 	struct work_struct	unbound_release_work;
+@@ -321,6 +328,8 @@
+ struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly;
+ EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);
+ 
++static DEFINE_LOCAL_IRQ_LOCK(pendingb_lock);
++
+ static int worker_thread(void *__worker);
+ static void copy_workqueue_attrs(struct workqueue_attrs *to,
+ 				 const struct workqueue_attrs *from);
+@@ -329,14 +338,14 @@
+ #include <trace/events/workqueue.h>
+ 
+ #define assert_rcu_or_pool_mutex()					\
+-	rcu_lockdep_assert(rcu_read_lock_sched_held() ||		\
++	rcu_lockdep_assert(rcu_read_lock_held() ||			\
+ 			   lockdep_is_held(&wq_pool_mutex),		\
+-			   "sched RCU or wq_pool_mutex should be held")
++			   "RCU or wq_pool_mutex should be held")
+ 
+ #define assert_rcu_or_wq_mutex(wq)					\
+-	rcu_lockdep_assert(rcu_read_lock_sched_held() ||		\
++	rcu_lockdep_assert(rcu_read_lock_held() ||			\
+ 			   lockdep_is_held(&wq->mutex),			\
+-			   "sched RCU or wq->mutex should be held")
++			   "RCU or wq->mutex should be held")
+ 
+ #define for_each_cpu_worker_pool(pool, cpu)				\
+ 	for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0];		\
+@@ -348,7 +357,7 @@
+  * @pool: iteration cursor
+  * @pi: integer used for iteration
+  *
+- * This must be called either with wq_pool_mutex held or sched RCU read
++ * This must be called either with wq_pool_mutex held or RCU read
+  * locked.  If the pool needs to be used beyond the locking in effect, the
+  * caller is responsible for guaranteeing that the pool stays online.
+  *
+@@ -380,7 +389,7 @@
+  * @pwq: iteration cursor
+  * @wq: the target workqueue
+  *
+- * This must be called either with wq->mutex held or sched RCU read locked.
++ * This must be called either with wq->mutex held or RCU read locked.
+  * If the pwq needs to be used beyond the locking in effect, the caller is
+  * responsible for guaranteeing that the pwq stays online.
+  *
+@@ -392,6 +401,31 @@
+ 		if (({ assert_rcu_or_wq_mutex(wq); false; })) { }	\
+ 		else
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++static inline void rt_lock_idle_list(struct worker_pool *pool)
++{
++	preempt_disable();
++}
++static inline void rt_unlock_idle_list(struct worker_pool *pool)
++{
++	preempt_enable();
++}
++static inline void sched_lock_idle_list(struct worker_pool *pool) { }
++static inline void sched_unlock_idle_list(struct worker_pool *pool) { }
++#else
++static inline void rt_lock_idle_list(struct worker_pool *pool) { }
++static inline void rt_unlock_idle_list(struct worker_pool *pool) { }
++static inline void sched_lock_idle_list(struct worker_pool *pool)
++{
++	spin_lock_irq(&pool->lock);
++}
++static inline void sched_unlock_idle_list(struct worker_pool *pool)
++{
++	spin_unlock_irq(&pool->lock);
++}
++#endif
++
++
+ #ifdef CONFIG_DEBUG_OBJECTS_WORK
+ 
+ static struct debug_obj_descr work_debug_descr;
+@@ -542,7 +576,7 @@
+  * @wq: the target workqueue
+  * @node: the node ID
+  *
+- * This must be called either with pwq_lock held or sched RCU read locked.
++ * This must be called either with pwq_lock held or RCU read locked.
+  * If the pwq needs to be used beyond the locking in effect, the caller is
+  * responsible for guaranteeing that the pwq stays online.
+  *
+@@ -646,8 +680,8 @@
+  * @work: the work item of interest
+  *
+  * Pools are created and destroyed under wq_pool_mutex, and allows read
+- * access under sched-RCU read lock.  As such, this function should be
+- * called under wq_pool_mutex or with preemption disabled.
++ * access under RCU read lock.  As such, this function should be
++ * called under wq_pool_mutex or inside of a rcu_read_lock() region.
+  *
+  * All fields of the returned pool are accessible as long as the above
+  * mentioned locking is in effect.  If the returned pool needs to be used
+@@ -784,51 +818,44 @@
+  */
+ static void wake_up_worker(struct worker_pool *pool)
+ {
+-	struct worker *worker = first_idle_worker(pool);
++	struct worker *worker;
++
++	rt_lock_idle_list(pool);
++
++	worker = first_idle_worker(pool);
+ 
+ 	if (likely(worker))
+ 		wake_up_process(worker->task);
++
++	rt_unlock_idle_list(pool);
+ }
+ 
+ /**
+- * wq_worker_waking_up - a worker is waking up
+- * @task: task waking up
+- * @cpu: CPU @task is waking up to
+- *
+- * This function is called during try_to_wake_up() when a worker is
+- * being awoken.
++ * wq_worker_running - a worker is running again
++ * @task: task returning from sleep
+  *
+- * CONTEXT:
+- * spin_lock_irq(rq->lock)
++ * This function is called when a worker returns from schedule()
+  */
+-void wq_worker_waking_up(struct task_struct *task, int cpu)
++void wq_worker_running(struct task_struct *task)
+ {
+ 	struct worker *worker = kthread_data(task);
+ 
+-	if (!(worker->flags & WORKER_NOT_RUNNING)) {
+-		WARN_ON_ONCE(worker->pool->cpu != cpu);
++	if (!worker->sleeping)
++		return;
++	if (!(worker->flags & WORKER_NOT_RUNNING))
+ 		atomic_inc(&worker->pool->nr_running);
+-	}
++	worker->sleeping = 0;
+ }
+ 
+ /**
+  * wq_worker_sleeping - a worker is going to sleep
+  * @task: task going to sleep
+- * @cpu: CPU in question, must be the current CPU number
+- *
+- * This function is called during schedule() when a busy worker is
+- * going to sleep.  Worker on the same cpu can be woken up by
+- * returning pointer to its task.
+- *
+- * CONTEXT:
+- * spin_lock_irq(rq->lock)
+- *
+- * Return:
+- * Worker task on @cpu to wake up, %NULL if none.
++ * This function is called from schedule() when a busy worker is
++ * going to sleep.
+  */
+-struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
++void wq_worker_sleeping(struct task_struct *task)
+ {
+-	struct worker *worker = kthread_data(task), *to_wakeup = NULL;
++	struct worker *worker = kthread_data(task);
+ 	struct worker_pool *pool;
+ 
+ 	/*
+@@ -837,29 +864,26 @@
+ 	 * checking NOT_RUNNING.
+ 	 */
+ 	if (worker->flags & WORKER_NOT_RUNNING)
+-		return NULL;
++		return;
+ 
+ 	pool = worker->pool;
+ 
+-	/* this can only happen on the local cpu */
+-	if (WARN_ON_ONCE(cpu != raw_smp_processor_id() || pool->cpu != cpu))
+-		return NULL;
++	if (WARN_ON_ONCE(worker->sleeping))
++		return;
++
++	worker->sleeping = 1;
+ 
+ 	/*
+ 	 * The counterpart of the following dec_and_test, implied mb,
+ 	 * worklist not empty test sequence is in insert_work().
+ 	 * Please read comment there.
+-	 *
+-	 * NOT_RUNNING is clear.  This means that we're bound to and
+-	 * running on the local cpu w/ rq lock held and preemption
+-	 * disabled, which in turn means that none else could be
+-	 * manipulating idle_list, so dereferencing idle_list without pool
+-	 * lock is safe.
+ 	 */
+ 	if (atomic_dec_and_test(&pool->nr_running) &&
+-	    !list_empty(&pool->worklist))
+-		to_wakeup = first_idle_worker(pool);
+-	return to_wakeup ? to_wakeup->task : NULL;
++	    !list_empty(&pool->worklist)) {
++		sched_lock_idle_list(pool);
++		wake_up_worker(pool);
++		sched_unlock_idle_list(pool);
++	}
+ }
+ 
+ /**
+@@ -1053,12 +1077,12 @@
+ {
+ 	if (pwq) {
+ 		/*
+-		 * As both pwqs and pools are sched-RCU protected, the
++		 * As both pwqs and pools are RCU protected, the
+ 		 * following lock operations are safe.
+ 		 */
+-		spin_lock_irq(&pwq->pool->lock);
++		local_spin_lock_irq(pendingb_lock, &pwq->pool->lock);
+ 		put_pwq(pwq);
+-		spin_unlock_irq(&pwq->pool->lock);
++		local_spin_unlock_irq(pendingb_lock, &pwq->pool->lock);
+ 	}
+ }
+ 
+@@ -1160,7 +1184,7 @@
+ 	struct worker_pool *pool;
+ 	struct pool_workqueue *pwq;
+ 
+-	local_irq_save(*flags);
++	local_lock_irqsave(pendingb_lock, *flags);
+ 
+ 	/* try to steal the timer if it exists */
+ 	if (is_dwork) {
+@@ -1179,6 +1203,7 @@
+ 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
+ 		return 0;
+ 
++	rcu_read_lock();
+ 	/*
+ 	 * The queueing is in progress, or it is already queued. Try to
+ 	 * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
+@@ -1217,14 +1242,16 @@
+ 		set_work_pool_and_keep_pending(work, pool->id);
+ 
+ 		spin_unlock(&pool->lock);
++		rcu_read_unlock();
+ 		return 1;
+ 	}
+ 	spin_unlock(&pool->lock);
+ fail:
+-	local_irq_restore(*flags);
++	rcu_read_unlock();
++	local_unlock_irqrestore(pendingb_lock, *flags);
+ 	if (work_is_canceling(work))
+ 		return -ENOENT;
+-	cpu_relax();
++	cpu_chill();
+ 	return -EAGAIN;
+ }
+ 
+@@ -1293,7 +1320,7 @@
+ 	 * queued or lose PENDING.  Grabbing PENDING and queueing should
+ 	 * happen with IRQ disabled.
+ 	 */
+-	WARN_ON_ONCE(!irqs_disabled());
++	WARN_ON_ONCE_NONRT(!irqs_disabled());
+ 
+ 	debug_work_activate(work);
+ 
+@@ -1301,6 +1328,8 @@
+ 	if (unlikely(wq->flags & __WQ_DRAINING) &&
+ 	    WARN_ON_ONCE(!is_chained_work(wq)))
+ 		return;
++
++	rcu_read_lock();
+ retry:
+ 	if (req_cpu == WORK_CPU_UNBOUND)
+ 		cpu = raw_smp_processor_id();
+@@ -1357,10 +1386,8 @@
+ 	/* pwq determined, queue */
+ 	trace_workqueue_queue_work(req_cpu, pwq, work);
+ 
+-	if (WARN_ON(!list_empty(&work->entry))) {
+-		spin_unlock(&pwq->pool->lock);
+-		return;
+-	}
++	if (WARN_ON(!list_empty(&work->entry)))
++		goto out;
+ 
+ 	pwq->nr_in_flight[pwq->work_color]++;
+ 	work_flags = work_color_to_flags(pwq->work_color);
+@@ -1376,7 +1403,9 @@
+ 
+ 	insert_work(pwq, work, worklist, work_flags);
+ 
++out:
+ 	spin_unlock(&pwq->pool->lock);
++	rcu_read_unlock();
+ }
+ 
+ /**
+@@ -1396,14 +1425,14 @@
+ 	bool ret = false;
+ 	unsigned long flags;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(pendingb_lock,flags);
+ 
+ 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+ 		__queue_work(cpu, wq, work);
+ 		ret = true;
+ 	}
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pendingb_lock, flags);
+ 	return ret;
+ }
+ EXPORT_SYMBOL(queue_work_on);
+@@ -1470,14 +1499,14 @@
+ 	unsigned long flags;
+ 
+ 	/* read the comment in __queue_work() */
+-	local_irq_save(flags);
++	local_lock_irqsave(pendingb_lock, flags);
+ 
+ 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+ 		__queue_delayed_work(cpu, wq, dwork, delay);
+ 		ret = true;
+ 	}
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pendingb_lock, flags);
+ 	return ret;
+ }
+ EXPORT_SYMBOL(queue_delayed_work_on);
+@@ -1512,7 +1541,7 @@
+ 
+ 	if (likely(ret >= 0)) {
+ 		__queue_delayed_work(cpu, wq, dwork, delay);
+-		local_irq_restore(flags);
++		local_unlock_irqrestore(pendingb_lock, flags);
+ 	}
+ 
+ 	/* -ENOENT from try_to_grab_pending() becomes %true */
+@@ -1545,7 +1574,9 @@
+ 	worker->last_active = jiffies;
+ 
+ 	/* idle_list is LIFO */
++	rt_lock_idle_list(pool);
+ 	list_add(&worker->entry, &pool->idle_list);
++	rt_unlock_idle_list(pool);
+ 
+ 	if (too_many_workers(pool) && !timer_pending(&pool->idle_timer))
+ 		mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
+@@ -1578,7 +1609,9 @@
+ 		return;
+ 	worker_clr_flags(worker, WORKER_IDLE);
+ 	pool->nr_idle--;
++	rt_lock_idle_list(pool);
+ 	list_del_init(&worker->entry);
++	rt_unlock_idle_list(pool);
+ }
+ 
+ static struct worker *alloc_worker(int node)
+@@ -1746,7 +1779,9 @@
+ 	pool->nr_workers--;
+ 	pool->nr_idle--;
+ 
++	rt_lock_idle_list(pool);
+ 	list_del_init(&worker->entry);
++	rt_unlock_idle_list(pool);
+ 	worker->flags |= WORKER_DIE;
+ 	wake_up_process(worker->task);
+ }
+@@ -2641,14 +2676,14 @@
+ 
+ 	might_sleep();
+ 
+-	local_irq_disable();
++	rcu_read_lock();
+ 	pool = get_work_pool(work);
+ 	if (!pool) {
+-		local_irq_enable();
++		rcu_read_unlock();
+ 		return false;
+ 	}
+ 
+-	spin_lock(&pool->lock);
++	spin_lock_irq(&pool->lock);
+ 	/* see the comment in try_to_grab_pending() with the same code */
+ 	pwq = get_work_pwq(work);
+ 	if (pwq) {
+@@ -2675,10 +2710,11 @@
+ 	else
+ 		lock_map_acquire_read(&pwq->wq->lockdep_map);
+ 	lock_map_release(&pwq->wq->lockdep_map);
+-
++	rcu_read_unlock();
+ 	return true;
+ already_gone:
+ 	spin_unlock_irq(&pool->lock);
++	rcu_read_unlock();
+ 	return false;
+ }
+ 
+@@ -2727,7 +2763,7 @@
+ 
+ 	/* tell other tasks trying to grab @work to back off */
+ 	mark_work_canceling(work);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pendingb_lock, flags);
+ 
+ 	flush_work(work);
+ 	clear_work_data(work);
+@@ -2772,10 +2808,10 @@
+  */
+ bool flush_delayed_work(struct delayed_work *dwork)
+ {
+-	local_irq_disable();
++	local_lock_irq(pendingb_lock);
+ 	if (del_timer_sync(&dwork->timer))
+ 		__queue_work(dwork->cpu, dwork->wq, &dwork->work);
+-	local_irq_enable();
++	local_unlock_irq(pendingb_lock);
+ 	return flush_work(&dwork->work);
+ }
+ EXPORT_SYMBOL(flush_delayed_work);
+@@ -2810,7 +2846,7 @@
+ 
+ 	set_work_pool_and_clear_pending(&dwork->work,
+ 					get_work_pool_id(&dwork->work));
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pendingb_lock, flags);
+ 	return ret;
+ }
+ EXPORT_SYMBOL(cancel_delayed_work);
+@@ -2996,7 +3032,8 @@
+ 	const char *delim = "";
+ 	int node, written = 0;
+ 
+-	rcu_read_lock_sched();
++	get_online_cpus();
++	rcu_read_lock();
+ 	for_each_node(node) {
+ 		written += scnprintf(buf + written, PAGE_SIZE - written,
+ 				     "%s%d:%d", delim, node,
+@@ -3004,7 +3041,8 @@
+ 		delim = " ";
+ 	}
+ 	written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
+-	rcu_read_unlock_sched();
++	rcu_read_unlock();
++	put_online_cpus();
+ 
+ 	return written;
+ }
+@@ -3372,7 +3410,7 @@
+  * put_unbound_pool - put a worker_pool
+  * @pool: worker_pool to put
+  *
+- * Put @pool.  If its refcnt reaches zero, it gets destroyed in sched-RCU
++ * Put @pool.  If its refcnt reaches zero, it gets destroyed in RCU
+  * safe manner.  get_unbound_pool() calls this function on its failure path
+  * and this function should be able to release pools which went through,
+  * successfully or not, init_worker_pool().
+@@ -3426,8 +3464,8 @@
+ 	del_timer_sync(&pool->idle_timer);
+ 	del_timer_sync(&pool->mayday_timer);
+ 
+-	/* sched-RCU protected to allow dereferences from get_work_pool() */
+-	call_rcu_sched(&pool->rcu, rcu_free_pool);
++	/* RCU protected to allow dereferences from get_work_pool() */
++	call_rcu(&pool->rcu, rcu_free_pool);
+ }
+ 
+ /**
+@@ -3532,7 +3570,7 @@
+ 	put_unbound_pool(pool);
+ 	mutex_unlock(&wq_pool_mutex);
+ 
+-	call_rcu_sched(&pwq->rcu, rcu_free_pwq);
++	call_rcu(&pwq->rcu, rcu_free_pwq);
+ 
+ 	/*
+ 	 * If we're the last pwq going away, @wq is already dead and no one
+@@ -4244,7 +4282,8 @@
+ 	struct pool_workqueue *pwq;
+ 	bool ret;
+ 
+-	rcu_read_lock_sched();
++	rcu_read_lock();
++	preempt_disable();
+ 
+ 	if (cpu == WORK_CPU_UNBOUND)
+ 		cpu = smp_processor_id();
+@@ -4255,7 +4294,8 @@
+ 		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+ 
+ 	ret = !list_empty(&pwq->delayed_works);
+-	rcu_read_unlock_sched();
++	preempt_enable();
++	rcu_read_unlock();
+ 
+ 	return ret;
+ }
+@@ -4281,16 +4321,15 @@
+ 	if (work_pending(work))
+ 		ret |= WORK_BUSY_PENDING;
+ 
+-	local_irq_save(flags);
++	rcu_read_lock();
+ 	pool = get_work_pool(work);
+ 	if (pool) {
+-		spin_lock(&pool->lock);
++		spin_lock_irqsave(&pool->lock, flags);
+ 		if (find_worker_executing_work(pool, work))
+ 			ret |= WORK_BUSY_RUNNING;
+-		spin_unlock(&pool->lock);
++		spin_unlock_irqrestore(&pool->lock, flags);
+ 	}
+-	local_irq_restore(flags);
+-
++	rcu_read_unlock();
+ 	return ret;
+ }
+ EXPORT_SYMBOL_GPL(work_busy);
+@@ -4719,16 +4758,16 @@
+ 		 * nr_active is monotonically decreasing.  It's safe
+ 		 * to peek without lock.
+ 		 */
+-		rcu_read_lock_sched();
++		rcu_read_lock();
+ 		for_each_pwq(pwq, wq) {
+ 			WARN_ON_ONCE(pwq->nr_active < 0);
+ 			if (pwq->nr_active) {
+ 				busy = true;
+-				rcu_read_unlock_sched();
++				rcu_read_unlock();
+ 				goto out_unlock;
+ 			}
+ 		}
+-		rcu_read_unlock_sched();
++		rcu_read_unlock();
+ 	}
+ out_unlock:
+ 	mutex_unlock(&wq_pool_mutex);
+diff -Nur linux-3.18.8.orig/kernel/workqueue_internal.h linux-3.18.8/kernel/workqueue_internal.h
+--- linux-3.18.8.orig/kernel/workqueue_internal.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/kernel/workqueue_internal.h	2015-03-03 08:05:18.000000000 +0100
+@@ -43,6 +43,7 @@
+ 	unsigned long		last_active;	/* L: last active timestamp */
+ 	unsigned int		flags;		/* X: flags */
+ 	int			id;		/* I: worker id */
++	int			sleeping;	/* None */
+ 
+ 	/*
+ 	 * Opaque string set with work_set_desc().  Printed out with task
+@@ -68,7 +69,7 @@
+  * Scheduler hooks for concurrency managed workqueue.  Only to be used from
+  * sched/core.c and workqueue.c.
+  */
+-void wq_worker_waking_up(struct task_struct *task, int cpu);
+-struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu);
++void wq_worker_running(struct task_struct *task);
++void wq_worker_sleeping(struct task_struct *task);
+ 
+ #endif /* _KERNEL_WORKQUEUE_INTERNAL_H */
+diff -Nur linux-3.18.8.orig/lib/debugobjects.c linux-3.18.8/lib/debugobjects.c
+--- linux-3.18.8.orig/lib/debugobjects.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/debugobjects.c	2015-03-03 08:05:18.000000000 +0100
+@@ -309,7 +309,10 @@
+ 	struct debug_obj *obj;
+ 	unsigned long flags;
+ 
+-	fill_pool();
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (preempt_count() == 0 && !irqs_disabled())
++#endif
++		fill_pool();
+ 
+ 	db = get_bucket((unsigned long) addr);
+ 
+diff -Nur linux-3.18.8.orig/lib/idr.c linux-3.18.8/lib/idr.c
+--- linux-3.18.8.orig/lib/idr.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/idr.c	2015-03-03 08:05:18.000000000 +0100
+@@ -31,6 +31,7 @@
+ #include <linux/spinlock.h>
+ #include <linux/percpu.h>
+ #include <linux/hardirq.h>
++#include <linux/locallock.h>
+ 
+ #define MAX_IDR_SHIFT		(sizeof(int) * 8 - 1)
+ #define MAX_IDR_BIT		(1U << MAX_IDR_SHIFT)
+@@ -367,6 +368,35 @@
+ 	idr_mark_full(pa, id);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++static DEFINE_LOCAL_IRQ_LOCK(idr_lock);
++
++static inline void idr_preload_lock(void)
++{
++	local_lock(idr_lock);
++}
++
++static inline void idr_preload_unlock(void)
++{
++	local_unlock(idr_lock);
++}
++
++void idr_preload_end(void)
++{
++	idr_preload_unlock();
++}
++EXPORT_SYMBOL(idr_preload_end);
++#else
++static inline void idr_preload_lock(void)
++{
++	preempt_disable();
++}
++
++static inline void idr_preload_unlock(void)
++{
++	preempt_enable();
++}
++#endif
+ 
+ /**
+  * idr_preload - preload for idr_alloc()
+@@ -402,7 +432,7 @@
+ 	WARN_ON_ONCE(in_interrupt());
+ 	might_sleep_if(gfp_mask & __GFP_WAIT);
+ 
+-	preempt_disable();
++	idr_preload_lock();
+ 
+ 	/*
+ 	 * idr_alloc() is likely to succeed w/o full idr_layer buffer and
+@@ -414,9 +444,9 @@
+ 	while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
+ 		struct idr_layer *new;
+ 
+-		preempt_enable();
++		idr_preload_unlock();
+ 		new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
+-		preempt_disable();
++		idr_preload_lock();
+ 		if (!new)
+ 			break;
+ 
+diff -Nur linux-3.18.8.orig/lib/Kconfig linux-3.18.8/lib/Kconfig
+--- linux-3.18.8.orig/lib/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -383,6 +383,7 @@
+ 
+ config CPUMASK_OFFSTACK
+ 	bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
++	depends on !PREEMPT_RT_FULL
+ 	help
+ 	  Use dynamic allocation for cpumask_var_t, instead of putting
+ 	  them on the stack.  This is a bit more expensive, but avoids
+diff -Nur linux-3.18.8.orig/lib/Kconfig.debug linux-3.18.8/lib/Kconfig.debug
+--- linux-3.18.8.orig/lib/Kconfig.debug	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/Kconfig.debug	2015-03-03 08:05:18.000000000 +0100
+@@ -639,7 +639,7 @@
+ 
+ config DEBUG_SHIRQ
+ 	bool "Debug shared IRQ handlers"
+-	depends on DEBUG_KERNEL
++	depends on DEBUG_KERNEL && !PREEMPT_RT_BASE
+ 	help
+ 	  Enable this to generate a spurious interrupt as soon as a shared
+ 	  interrupt handler is registered, and just before one is deregistered.
+diff -Nur linux-3.18.8.orig/lib/locking-selftest.c linux-3.18.8/lib/locking-selftest.c
+--- linux-3.18.8.orig/lib/locking-selftest.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/locking-selftest.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1858,6 +1858,7 @@
+ 
+ 	printk("  --------------------------------------------------------------------------\n");
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	/*
+ 	 * irq-context testcases:
+ 	 */
+@@ -1870,6 +1871,28 @@
+ 
+ 	DO_TESTCASE_6x2("irq read-recursion", irq_read_recursion);
+ //	DO_TESTCASE_6x2B("irq read-recursion #2", irq_read_recursion2);
++#else
++	/* On -rt, we only do hardirq context test for raw spinlock */
++	DO_TESTCASE_1B("hard-irqs-on + irq-safe-A", irqsafe1_hard_spin, 12);
++	DO_TESTCASE_1B("hard-irqs-on + irq-safe-A", irqsafe1_hard_spin, 21);
++
++	DO_TESTCASE_1B("hard-safe-A + irqs-on", irqsafe2B_hard_spin, 12);
++	DO_TESTCASE_1B("hard-safe-A + irqs-on", irqsafe2B_hard_spin, 21);
++
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 123);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 132);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 213);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 231);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 312);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 321);
++
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 123);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 132);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 213);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 231);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 312);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 321);
++#endif
+ 
+ 	ww_tests();
+ 
+diff -Nur linux-3.18.8.orig/lib/percpu_ida.c linux-3.18.8/lib/percpu_ida.c
+--- linux-3.18.8.orig/lib/percpu_ida.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/percpu_ida.c	2015-03-03 08:05:18.000000000 +0100
+@@ -29,6 +29,9 @@
+ #include <linux/string.h>
+ #include <linux/spinlock.h>
+ #include <linux/percpu_ida.h>
++#include <linux/locallock.h>
++
++static DEFINE_LOCAL_IRQ_LOCK(irq_off_lock);
+ 
+ struct percpu_ida_cpu {
+ 	/*
+@@ -151,13 +154,13 @@
+ 	unsigned long flags;
+ 	int tag;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(irq_off_lock, flags);
+ 	tags = this_cpu_ptr(pool->tag_cpu);
+ 
+ 	/* Fastpath */
+ 	tag = alloc_local_tag(tags);
+ 	if (likely(tag >= 0)) {
+-		local_irq_restore(flags);
++		local_unlock_irqrestore(irq_off_lock, flags);
+ 		return tag;
+ 	}
+ 
+@@ -176,6 +179,7 @@
+ 
+ 		if (!tags->nr_free)
+ 			alloc_global_tags(pool, tags);
++
+ 		if (!tags->nr_free)
+ 			steal_tags(pool, tags);
+ 
+@@ -187,7 +191,7 @@
+ 		}
+ 
+ 		spin_unlock(&pool->lock);
+-		local_irq_restore(flags);
++		local_unlock_irqrestore(irq_off_lock, flags);
+ 
+ 		if (tag >= 0 || state == TASK_RUNNING)
+ 			break;
+@@ -199,7 +203,7 @@
+ 
+ 		schedule();
+ 
+-		local_irq_save(flags);
++		local_lock_irqsave(irq_off_lock, flags);
+ 		tags = this_cpu_ptr(pool->tag_cpu);
+ 	}
+ 	if (state != TASK_RUNNING)
+@@ -224,7 +228,7 @@
+ 
+ 	BUG_ON(tag >= pool->nr_tags);
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(irq_off_lock, flags);
+ 	tags = this_cpu_ptr(pool->tag_cpu);
+ 
+ 	spin_lock(&tags->lock);
+@@ -256,7 +260,7 @@
+ 		spin_unlock(&pool->lock);
+ 	}
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(irq_off_lock, flags);
+ }
+ EXPORT_SYMBOL_GPL(percpu_ida_free);
+ 
+@@ -348,7 +352,7 @@
+ 	struct percpu_ida_cpu *remote;
+ 	unsigned cpu, i, err = 0;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(irq_off_lock, flags);
+ 	for_each_possible_cpu(cpu) {
+ 		remote = per_cpu_ptr(pool->tag_cpu, cpu);
+ 		spin_lock(&remote->lock);
+@@ -370,7 +374,7 @@
+ 	}
+ 	spin_unlock(&pool->lock);
+ out:
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(irq_off_lock, flags);
+ 	return err;
+ }
+ EXPORT_SYMBOL_GPL(percpu_ida_for_each_free);
+diff -Nur linux-3.18.8.orig/lib/radix-tree.c linux-3.18.8/lib/radix-tree.c
+--- linux-3.18.8.orig/lib/radix-tree.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/radix-tree.c	2015-03-03 08:05:18.000000000 +0100
+@@ -195,12 +195,13 @@
+ 		 * succeed in getting a node here (and never reach
+ 		 * kmem_cache_alloc)
+ 		 */
+-		rtp = this_cpu_ptr(&radix_tree_preloads);
++		rtp = &get_cpu_var(radix_tree_preloads);
+ 		if (rtp->nr) {
+ 			ret = rtp->nodes[rtp->nr - 1];
+ 			rtp->nodes[rtp->nr - 1] = NULL;
+ 			rtp->nr--;
+ 		}
++		put_cpu_var(radix_tree_preloads);
+ 		/*
+ 		 * Update the allocation stack trace as this is more useful
+ 		 * for debugging.
+@@ -240,6 +241,7 @@
+ 	call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /*
+  * Load up this CPU's radix_tree_node buffer with sufficient objects to
+  * ensure that the addition of a single element in the tree cannot fail.  On
+@@ -305,6 +307,7 @@
+ 	return 0;
+ }
+ EXPORT_SYMBOL(radix_tree_maybe_preload);
++#endif
+ 
+ /*
+  *	Return the maximum key which can be store into a
+diff -Nur linux-3.18.8.orig/lib/scatterlist.c linux-3.18.8/lib/scatterlist.c
+--- linux-3.18.8.orig/lib/scatterlist.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/scatterlist.c	2015-03-03 08:05:18.000000000 +0100
+@@ -592,7 +592,7 @@
+ 			flush_kernel_dcache_page(miter->page);
+ 
+ 		if (miter->__flags & SG_MITER_ATOMIC) {
+-			WARN_ON_ONCE(preemptible());
++			WARN_ON_ONCE(!pagefault_disabled());
+ 			kunmap_atomic(miter->addr);
+ 		} else
+ 			kunmap(miter->page);
+@@ -637,7 +637,7 @@
+ 	if (!sg_miter_skip(&miter, skip))
+ 		return false;
+ 
+-	local_irq_save(flags);
++	local_irq_save_nort(flags);
+ 
+ 	while (sg_miter_next(&miter) && offset < buflen) {
+ 		unsigned int len;
+@@ -654,7 +654,7 @@
+ 
+ 	sg_miter_stop(&miter);
+ 
+-	local_irq_restore(flags);
++	local_irq_restore_nort(flags);
+ 	return offset;
+ }
+ 
+diff -Nur linux-3.18.8.orig/lib/smp_processor_id.c linux-3.18.8/lib/smp_processor_id.c
+--- linux-3.18.8.orig/lib/smp_processor_id.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/lib/smp_processor_id.c	2015-03-03 08:05:18.000000000 +0100
+@@ -39,8 +39,9 @@
+ 	if (!printk_ratelimit())
+ 		goto out_enable;
+ 
+-	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
+-		what1, what2, preempt_count() - 1, current->comm, current->pid);
++	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x %08x] code: %s/%d\n",
++		what1, what2, preempt_count() - 1, __migrate_disabled(current),
++		current->comm, current->pid);
+ 
+ 	print_symbol("caller is %s\n", (long)__builtin_return_address(0));
+ 	dump_stack();
+diff -Nur linux-3.18.8.orig/mm/filemap.c linux-3.18.8/mm/filemap.c
+--- linux-3.18.8.orig/mm/filemap.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/filemap.c	2015-03-03 08:05:18.000000000 +0100
+@@ -168,7 +168,9 @@
+ 	if (!workingset_node_pages(node) &&
+ 	    list_empty(&node->private_list)) {
+ 		node->private_data = mapping;
+-		list_lru_add(&workingset_shadow_nodes, &node->private_list);
++		local_lock(workingset_shadow_lock);
++		list_lru_add(&__workingset_shadow_nodes, &node->private_list);
++		local_unlock(workingset_shadow_lock);
+ 	}
+ }
+ 
+@@ -535,9 +537,12 @@
+ 		 * node->private_list is protected by
+ 		 * mapping->tree_lock.
+ 		 */
+-		if (!list_empty(&node->private_list))
+-			list_lru_del(&workingset_shadow_nodes,
++		if (!list_empty(&node->private_list)) {
++			local_lock(workingset_shadow_lock);
++			list_lru_del(&__workingset_shadow_nodes,
+ 				     &node->private_list);
++			local_unlock(workingset_shadow_lock);
++		}
+ 	}
+ 	return 0;
+ }
+diff -Nur linux-3.18.8.orig/mm/highmem.c linux-3.18.8/mm/highmem.c
+--- linux-3.18.8.orig/mm/highmem.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/highmem.c	2015-03-03 08:05:18.000000000 +0100
+@@ -29,10 +29,11 @@
+ #include <linux/kgdb.h>
+ #include <asm/tlbflush.h>
+ 
+-
++#ifndef CONFIG_PREEMPT_RT_FULL
+ #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
+ DEFINE_PER_CPU(int, __kmap_atomic_idx);
+ #endif
++#endif
+ 
+ /*
+  * Virtual_count is not a pure "count".
+@@ -107,8 +108,9 @@
+ unsigned long totalhigh_pages __read_mostly;
+ EXPORT_SYMBOL(totalhigh_pages);
+ 
+-
++#ifndef CONFIG_PREEMPT_RT_FULL
+ EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx);
++#endif
+ 
+ unsigned int nr_free_highpages (void)
+ {
+diff -Nur linux-3.18.8.orig/mm/Kconfig linux-3.18.8/mm/Kconfig
+--- linux-3.18.8.orig/mm/Kconfig	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/Kconfig	2015-03-03 08:05:18.000000000 +0100
+@@ -408,7 +408,7 @@
+ 
+ config TRANSPARENT_HUGEPAGE
+ 	bool "Transparent Hugepage Support"
+-	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
++	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT_FULL
+ 	select COMPACTION
+ 	help
+ 	  Transparent Hugepages allows the kernel to use huge pages and
+diff -Nur linux-3.18.8.orig/mm/memcontrol.c linux-3.18.8/mm/memcontrol.c
+--- linux-3.18.8.orig/mm/memcontrol.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/memcontrol.c	2015-03-03 08:05:18.000000000 +0100
+@@ -60,6 +60,8 @@
+ #include <net/sock.h>
+ #include <net/ip.h>
+ #include <net/tcp_memcontrol.h>
++#include <linux/locallock.h>
++
+ #include "slab.h"
+ 
+ #include <asm/uaccess.h>
+@@ -87,6 +89,7 @@
+ #define do_swap_account		0
+ #endif
+ 
++static DEFINE_LOCAL_IRQ_LOCK(event_lock);
+ 
+ static const char * const mem_cgroup_stat_names[] = {
+ 	"cache",
+@@ -2376,14 +2379,17 @@
+  */
+ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+ {
+-	struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
++	struct memcg_stock_pcp *stock;
++	int cpu = get_cpu_light();
++
++	stock = &per_cpu(memcg_stock, cpu);
+ 
+ 	if (stock->cached != memcg) { /* reset if necessary */
+ 		drain_stock(stock);
+ 		stock->cached = memcg;
+ 	}
+ 	stock->nr_pages += nr_pages;
+-	put_cpu_var(memcg_stock);
++	put_cpu_light();
+ }
+ 
+ /*
+@@ -2397,7 +2403,7 @@
+ 
+ 	/* Notify other cpus that system-wide "drain" is running */
+ 	get_online_cpus();
+-	curcpu = get_cpu();
++	curcpu = get_cpu_light();
+ 	for_each_online_cpu(cpu) {
+ 		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
+ 		struct mem_cgroup *memcg;
+@@ -2414,7 +2420,7 @@
+ 				schedule_work_on(cpu, &stock->work);
+ 		}
+ 	}
+-	put_cpu();
++	put_cpu_light();
+ 
+ 	if (!sync)
+ 		goto out;
+@@ -3419,12 +3425,12 @@
+ 	move_unlock_mem_cgroup(from, &flags);
+ 	ret = 0;
+ 
+-	local_irq_disable();
++	local_lock_irq(event_lock);
+ 	mem_cgroup_charge_statistics(to, page, nr_pages);
+ 	memcg_check_events(to, page);
+ 	mem_cgroup_charge_statistics(from, page, -nr_pages);
+ 	memcg_check_events(from, page);
+-	local_irq_enable();
++	local_unlock_irq(event_lock);
+ out_unlock:
+ 	unlock_page(page);
+ out:
+@@ -6406,10 +6412,10 @@
+ 		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ 	}
+ 
+-	local_irq_disable();
++	local_lock_irq(event_lock);
+ 	mem_cgroup_charge_statistics(memcg, page, nr_pages);
+ 	memcg_check_events(memcg, page);
+-	local_irq_enable();
++	local_unlock_irq(event_lock);
+ 
+ 	if (do_swap_account && PageSwapCache(page)) {
+ 		swp_entry_t entry = { .val = page_private(page) };
+@@ -6468,14 +6474,14 @@
+ 		memcg_oom_recover(memcg);
+ 	}
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(event_lock, flags);
+ 	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
+ 	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
+ 	__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
+ 	__this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
+ 	__this_cpu_add(memcg->stat->nr_page_events, nr_anon + nr_file);
+ 	memcg_check_events(memcg, dummy_page);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(event_lock, flags);
+ }
+ 
+ static void uncharge_list(struct list_head *page_list)
+diff -Nur linux-3.18.8.orig/mm/memory.c linux-3.18.8/mm/memory.c
+--- linux-3.18.8.orig/mm/memory.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/memory.c	2015-03-03 08:05:18.000000000 +0100
+@@ -3258,6 +3258,32 @@
+ 	return 0;
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++void pagefault_disable(void)
++{
++	migrate_disable();
++	current->pagefault_disabled++;
++	/*
++	 * make sure to have issued the store before a pagefault
++	 * can hit.
++	 */
++	barrier();
++}
++EXPORT_SYMBOL(pagefault_disable);
++
++void pagefault_enable(void)
++{
++	/*
++	 * make sure to issue those last loads/stores before enabling
++	 * the pagefault handler again.
++	 */
++	barrier();
++	current->pagefault_disabled--;
++	migrate_enable();
++}
++EXPORT_SYMBOL(pagefault_enable);
++#endif
++
+ /*
+  * By the time we get here, we already hold the mm semaphore
+  *
+diff -Nur linux-3.18.8.orig/mm/mmu_context.c linux-3.18.8/mm/mmu_context.c
+--- linux-3.18.8.orig/mm/mmu_context.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/mmu_context.c	2015-03-03 08:05:18.000000000 +0100
+@@ -23,6 +23,7 @@
+ 	struct task_struct *tsk = current;
+ 
+ 	task_lock(tsk);
++	preempt_disable_rt();
+ 	active_mm = tsk->active_mm;
+ 	if (active_mm != mm) {
+ 		atomic_inc(&mm->mm_count);
+@@ -30,6 +31,7 @@
+ 	}
+ 	tsk->mm = mm;
+ 	switch_mm(active_mm, mm, tsk);
++	preempt_enable_rt();
+ 	task_unlock(tsk);
+ #ifdef finish_arch_post_lock_switch
+ 	finish_arch_post_lock_switch();
+diff -Nur linux-3.18.8.orig/mm/page_alloc.c linux-3.18.8/mm/page_alloc.c
+--- linux-3.18.8.orig/mm/page_alloc.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/page_alloc.c	2015-03-03 08:05:18.000000000 +0100
+@@ -59,6 +59,7 @@
+ #include <linux/page-debug-flags.h>
+ #include <linux/hugetlb.h>
+ #include <linux/sched/rt.h>
++#include <linux/locallock.h>
+ 
+ #include <asm/sections.h>
+ #include <asm/tlbflush.h>
+@@ -230,6 +231,18 @@
+ EXPORT_SYMBOL(nr_online_nodes);
+ #endif
+ 
++static DEFINE_LOCAL_IRQ_LOCK(pa_lock);
++
++#ifdef CONFIG_PREEMPT_RT_BASE
++# define cpu_lock_irqsave(cpu, flags)		\
++	local_lock_irqsave_on(pa_lock, flags, cpu)
++# define cpu_unlock_irqrestore(cpu, flags)	\
++	local_unlock_irqrestore_on(pa_lock, flags, cpu)
++#else
++# define cpu_lock_irqsave(cpu, flags)		local_irq_save(flags)
++# define cpu_unlock_irqrestore(cpu, flags)	local_irq_restore(flags)
++#endif
++
+ int page_group_by_mobility_disabled __read_mostly;
+ 
+ void set_pageblock_migratetype(struct page *page, int migratetype)
+@@ -654,7 +667,7 @@
+ }
+ 
+ /*
+- * Frees a number of pages from the PCP lists
++ * Frees a number of pages which have been collected from the pcp lists.
+  * Assumes all pages on list are in same zone, and of same order.
+  * count is the number of pages to free.
+  *
+@@ -665,18 +678,51 @@
+  * pinned" detection logic.
+  */
+ static void free_pcppages_bulk(struct zone *zone, int count,
+-					struct per_cpu_pages *pcp)
++			       struct list_head *list)
+ {
+-	int migratetype = 0;
+-	int batch_free = 0;
+ 	int to_free = count;
+ 	unsigned long nr_scanned;
++	unsigned long flags;
++
++	spin_lock_irqsave(&zone->lock, flags);
+ 
+-	spin_lock(&zone->lock);
+ 	nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
+ 	if (nr_scanned)
+ 		__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
+ 
++	while (!list_empty(list)) {
++		struct page *page = list_first_entry(list, struct page, lru);
++		int mt;	/* migratetype of the to-be-freed page */
++
++		/* must delete as __free_one_page list manipulates */
++		list_del(&page->lru);
++
++		mt = get_freepage_migratetype(page);
++		if (unlikely(has_isolate_pageblock(zone)))
++			mt = get_pageblock_migratetype(page);
++
++		/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
++		__free_one_page(page, page_to_pfn(page), zone, 0, mt);
++		trace_mm_page_pcpu_drain(page, 0, mt);
++		to_free--;
++	}
++	WARN_ON(to_free != 0);
++	spin_unlock_irqrestore(&zone->lock, flags);
++}
++
++/*
++ * Moves a number of pages from the PCP lists to free list which
++ * is freed outside of the locked region.
++ *
++ * Assumes all pages on list are in same zone, and of same order.
++ * count is the number of pages to free.
++ */
++static void isolate_pcp_pages(int to_free, struct per_cpu_pages *src,
++			      struct list_head *dst)
++{
++	int migratetype = 0;
++	int batch_free = 0;
++
+ 	while (to_free) {
+ 		struct page *page;
+ 		struct list_head *list;
+@@ -692,7 +738,7 @@
+ 			batch_free++;
+ 			if (++migratetype == MIGRATE_PCPTYPES)
+ 				migratetype = 0;
+-			list = &pcp->lists[migratetype];
++			list = &src->lists[migratetype];
+ 		} while (list_empty(list));
+ 
+ 		/* This is the only non-empty list. Free them all. */
+@@ -700,21 +746,11 @@
+ 			batch_free = to_free;
+ 
+ 		do {
+-			int mt;	/* migratetype of the to-be-freed page */
+-
+-			page = list_entry(list->prev, struct page, lru);
+-			/* must delete as __free_one_page list manipulates */
++			page = list_last_entry(list, struct page, lru);
+ 			list_del(&page->lru);
+-			mt = get_freepage_migratetype(page);
+-			if (unlikely(has_isolate_pageblock(zone)))
+-				mt = get_pageblock_migratetype(page);
+-
+-			/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
+-			__free_one_page(page, page_to_pfn(page), zone, 0, mt);
+-			trace_mm_page_pcpu_drain(page, 0, mt);
++			list_add(&page->lru, dst);
+ 		} while (--to_free && --batch_free && !list_empty(list));
+ 	}
+-	spin_unlock(&zone->lock);
+ }
+ 
+ static void free_one_page(struct zone *zone,
+@@ -723,7 +759,9 @@
+ 				int migratetype)
+ {
+ 	unsigned long nr_scanned;
+-	spin_lock(&zone->lock);
++	unsigned long flags;
++
++	spin_lock_irqsave(&zone->lock, flags);
+ 	nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
+ 	if (nr_scanned)
+ 		__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
+@@ -733,7 +771,7 @@
+ 		migratetype = get_pfnblock_migratetype(page, pfn);
+ 	}
+ 	__free_one_page(page, pfn, zone, order, migratetype);
+-	spin_unlock(&zone->lock);
++	spin_unlock_irqrestore(&zone->lock, flags);
+ }
+ 
+ static bool free_pages_prepare(struct page *page, unsigned int order)
+@@ -773,11 +811,11 @@
+ 		return;
+ 
+ 	migratetype = get_pfnblock_migratetype(page, pfn);
+-	local_irq_save(flags);
++	local_lock_irqsave(pa_lock, flags);
+ 	__count_vm_events(PGFREE, 1 << order);
+ 	set_freepage_migratetype(page, migratetype);
+ 	free_one_page(page_zone(page), page, pfn, order, migratetype);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pa_lock, flags);
+ }
+ 
+ void __init __free_pages_bootmem(struct page *page, unsigned int order)
+@@ -1253,16 +1291,18 @@
+ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
+ {
+ 	unsigned long flags;
++	LIST_HEAD(dst);
+ 	int to_drain, batch;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(pa_lock, flags);
+ 	batch = ACCESS_ONCE(pcp->batch);
+ 	to_drain = min(pcp->count, batch);
+ 	if (to_drain > 0) {
+-		free_pcppages_bulk(zone, to_drain, pcp);
++		isolate_pcp_pages(to_drain, pcp, &dst);
+ 		pcp->count -= to_drain;
+ 	}
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pa_lock, flags);
++	free_pcppages_bulk(zone, to_drain, &dst);
+ }
+ #endif
+ 
+@@ -1281,16 +1321,21 @@
+ 	for_each_populated_zone(zone) {
+ 		struct per_cpu_pageset *pset;
+ 		struct per_cpu_pages *pcp;
++		LIST_HEAD(dst);
++		int count;
+ 
+-		local_irq_save(flags);
++		cpu_lock_irqsave(cpu, flags);
+ 		pset = per_cpu_ptr(zone->pageset, cpu);
+ 
+ 		pcp = &pset->pcp;
+-		if (pcp->count) {
+-			free_pcppages_bulk(zone, pcp->count, pcp);
++		count = pcp->count;
++		if (count) {
++			isolate_pcp_pages(count, pcp, &dst);
+ 			pcp->count = 0;
+ 		}
+-		local_irq_restore(flags);
++		cpu_unlock_irqrestore(cpu, flags);
++		if (count)
++			free_pcppages_bulk(zone, count, &dst);
+ 	}
+ }
+ 
+@@ -1343,7 +1388,12 @@
+ 		else
+ 			cpumask_clear_cpu(cpu, &cpus_with_pcps);
+ 	}
++#ifndef CONFIG_PREEMPT_RT_BASE
+ 	on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
++#else
++	for_each_cpu(cpu, &cpus_with_pcps)
++		drain_pages(cpu);
++#endif
+ }
+ 
+ #ifdef CONFIG_HIBERNATION
+@@ -1399,7 +1449,7 @@
+ 
+ 	migratetype = get_pfnblock_migratetype(page, pfn);
+ 	set_freepage_migratetype(page, migratetype);
+-	local_irq_save(flags);
++	local_lock_irqsave(pa_lock, flags);
+ 	__count_vm_event(PGFREE);
+ 
+ 	/*
+@@ -1425,12 +1475,17 @@
+ 	pcp->count++;
+ 	if (pcp->count >= pcp->high) {
+ 		unsigned long batch = ACCESS_ONCE(pcp->batch);
+-		free_pcppages_bulk(zone, batch, pcp);
++		LIST_HEAD(dst);
++
++		isolate_pcp_pages(batch, pcp, &dst);
+ 		pcp->count -= batch;
++		local_unlock_irqrestore(pa_lock, flags);
++		free_pcppages_bulk(zone, batch, &dst);
++		return;
+ 	}
+ 
+ out:
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pa_lock, flags);
+ }
+ 
+ /*
+@@ -1560,7 +1615,7 @@
+ 		struct per_cpu_pages *pcp;
+ 		struct list_head *list;
+ 
+-		local_irq_save(flags);
++		local_lock_irqsave(pa_lock, flags);
+ 		pcp = &this_cpu_ptr(zone->pageset)->pcp;
+ 		list = &pcp->lists[migratetype];
+ 		if (list_empty(list)) {
+@@ -1592,13 +1647,15 @@
+ 			 */
+ 			WARN_ON_ONCE(order > 1);
+ 		}
+-		spin_lock_irqsave(&zone->lock, flags);
++		local_spin_lock_irqsave(pa_lock, &zone->lock, flags);
+ 		page = __rmqueue(zone, order, migratetype);
+-		spin_unlock(&zone->lock);
+-		if (!page)
++		if (!page) {
++			spin_unlock(&zone->lock);
+ 			goto failed;
++		}
+ 		__mod_zone_freepage_state(zone, -(1 << order),
+ 					  get_freepage_migratetype(page));
++		spin_unlock(&zone->lock);
+ 	}
+ 
+ 	__mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
+@@ -1608,7 +1665,7 @@
+ 
+ 	__count_zone_vm_events(PGALLOC, zone, 1 << order);
+ 	zone_statistics(preferred_zone, zone, gfp_flags);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pa_lock, flags);
+ 
+ 	VM_BUG_ON_PAGE(bad_range(zone, page), page);
+ 	if (prep_new_page(page, order, gfp_flags))
+@@ -1616,7 +1673,7 @@
+ 	return page;
+ 
+ failed:
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pa_lock, flags);
+ 	return NULL;
+ }
+ 
+@@ -2327,8 +2384,8 @@
+ 	count_vm_event(COMPACTSTALL);
+ 
+ 	/* Page migration frees to the PCP lists but we want merging */
+-	drain_pages(get_cpu());
+-	put_cpu();
++	drain_pages(get_cpu_light());
++	put_cpu_light();
+ 
+ 	page = get_page_from_freelist(gfp_mask, nodemask,
+ 			order, zonelist, high_zoneidx,
+@@ -5567,6 +5624,7 @@
+ void __init page_alloc_init(void)
+ {
+ 	hotcpu_notifier(page_alloc_cpu_notify, 0);
++	local_irq_lock_init(pa_lock);
+ }
+ 
+ /*
+@@ -6461,7 +6519,7 @@
+ 	struct per_cpu_pageset *pset;
+ 
+ 	/* avoid races with drain_pages()  */
+-	local_irq_save(flags);
++	local_lock_irqsave(pa_lock, flags);
+ 	if (zone->pageset != &boot_pageset) {
+ 		for_each_online_cpu(cpu) {
+ 			pset = per_cpu_ptr(zone->pageset, cpu);
+@@ -6470,7 +6528,7 @@
+ 		free_percpu(zone->pageset);
+ 		zone->pageset = &boot_pageset;
+ 	}
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(pa_lock, flags);
+ }
+ 
+ #ifdef CONFIG_MEMORY_HOTREMOVE
+diff -Nur linux-3.18.8.orig/mm/slab.h linux-3.18.8/mm/slab.h
+--- linux-3.18.8.orig/mm/slab.h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/slab.h	2015-03-03 08:05:18.000000000 +0100
+@@ -315,7 +315,11 @@
+  * The slab lists for all objects.
+  */
+ struct kmem_cache_node {
++#ifdef CONFIG_SLUB
++	raw_spinlock_t list_lock;
++#else
+ 	spinlock_t list_lock;
++#endif
+ 
+ #ifdef CONFIG_SLAB
+ 	struct list_head slabs_partial;	/* partial list first, better asm code */
+diff -Nur linux-3.18.8.orig/mm/slub.c linux-3.18.8/mm/slub.c
+--- linux-3.18.8.orig/mm/slub.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/slub.c	2015-03-03 08:05:18.000000000 +0100
+@@ -1044,7 +1044,7 @@
+ {
+ 	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+ 
+-	spin_lock_irqsave(&n->list_lock, *flags);
++	raw_spin_lock_irqsave(&n->list_lock, *flags);
+ 	slab_lock(page);
+ 
+ 	if (!check_slab(s, page))
+@@ -1091,7 +1091,7 @@
+ 
+ fail:
+ 	slab_unlock(page);
+-	spin_unlock_irqrestore(&n->list_lock, *flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, *flags);
+ 	slab_fix(s, "Object at 0x%p not freed", object);
+ 	return NULL;
+ }
+@@ -1219,6 +1219,12 @@
+ 
+ #endif /* CONFIG_SLUB_DEBUG */
+ 
++struct slub_free_list {
++	raw_spinlock_t		lock;
++	struct list_head	list;
++};
++static DEFINE_PER_CPU(struct slub_free_list, slub_free_list);
++
+ /*
+  * Hooks for other subsystems that check memory allocations. In a typical
+  * production configuration these hooks all should produce no code at all.
+@@ -1303,10 +1309,15 @@
+ 	struct page *page;
+ 	struct kmem_cache_order_objects oo = s->oo;
+ 	gfp_t alloc_gfp;
++	bool enableirqs;
+ 
+ 	flags &= gfp_allowed_mask;
+ 
+-	if (flags & __GFP_WAIT)
++	enableirqs = (flags & __GFP_WAIT) != 0;
++#ifdef CONFIG_PREEMPT_RT_FULL
++	enableirqs |= system_state == SYSTEM_RUNNING;
++#endif
++	if (enableirqs)
+ 		local_irq_enable();
+ 
+ 	flags |= s->allocflags;
+@@ -1347,7 +1358,7 @@
+ 			kmemcheck_mark_unallocated_pages(page, pages);
+ 	}
+ 
+-	if (flags & __GFP_WAIT)
++	if (enableirqs)
+ 		local_irq_disable();
+ 	if (!page)
+ 		return NULL;
+@@ -1365,8 +1376,10 @@
+ 				void *object)
+ {
+ 	setup_object_debug(s, page, object);
++#ifndef CONFIG_PREEMPT_RT_FULL
+ 	if (unlikely(s->ctor))
+ 		s->ctor(object);
++#endif
+ }
+ 
+ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
+@@ -1442,6 +1455,16 @@
+ 	memcg_uncharge_slab(s, order);
+ }
+ 
++static void free_delayed(struct list_head *h)
++{
++	while(!list_empty(h)) {
++		struct page *page = list_first_entry(h, struct page, lru);
++
++		list_del(&page->lru);
++		__free_slab(page->slab_cache, page);
++	}
++}
++
+ #define need_reserve_slab_rcu						\
+ 	(sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
+ 
+@@ -1476,6 +1499,12 @@
+ 		}
+ 
+ 		call_rcu(head, rcu_free_slab);
++	} else if (irqs_disabled()) {
++		struct slub_free_list *f = &__get_cpu_var(slub_free_list);
++
++		raw_spin_lock(&f->lock);
++		list_add(&page->lru, &f->list);
++		raw_spin_unlock(&f->lock);
+ 	} else
+ 		__free_slab(s, page);
+ }
+@@ -1589,7 +1618,7 @@
+ 	if (!n || !n->nr_partial)
+ 		return NULL;
+ 
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	list_for_each_entry_safe(page, page2, &n->partial, lru) {
+ 		void *t;
+ 
+@@ -1614,7 +1643,7 @@
+ 			break;
+ 
+ 	}
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	return object;
+ }
+ 
+@@ -1860,7 +1889,7 @@
+ 			 * that acquire_slab() will see a slab page that
+ 			 * is frozen
+ 			 */
+-			spin_lock(&n->list_lock);
++			raw_spin_lock(&n->list_lock);
+ 		}
+ 	} else {
+ 		m = M_FULL;
+@@ -1871,7 +1900,7 @@
+ 			 * slabs from diagnostic functions will not see
+ 			 * any frozen slabs.
+ 			 */
+-			spin_lock(&n->list_lock);
++			raw_spin_lock(&n->list_lock);
+ 		}
+ 	}
+ 
+@@ -1906,7 +1935,7 @@
+ 		goto redo;
+ 
+ 	if (lock)
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 
+ 	if (m == M_FREE) {
+ 		stat(s, DEACTIVATE_EMPTY);
+@@ -1938,10 +1967,10 @@
+ 		n2 = get_node(s, page_to_nid(page));
+ 		if (n != n2) {
+ 			if (n)
+-				spin_unlock(&n->list_lock);
++				raw_spin_unlock(&n->list_lock);
+ 
+ 			n = n2;
+-			spin_lock(&n->list_lock);
++			raw_spin_lock(&n->list_lock);
+ 		}
+ 
+ 		do {
+@@ -1970,7 +1999,7 @@
+ 	}
+ 
+ 	if (n)
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 
+ 	while (discard_page) {
+ 		page = discard_page;
+@@ -2008,14 +2037,21 @@
+ 			pobjects = oldpage->pobjects;
+ 			pages = oldpage->pages;
+ 			if (drain && pobjects > s->cpu_partial) {
++				struct slub_free_list *f;
+ 				unsigned long flags;
++				LIST_HEAD(tofree);
+ 				/*
+ 				 * partial array is full. Move the existing
+ 				 * set to the per node partial list.
+ 				 */
+ 				local_irq_save(flags);
+ 				unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
++				f = &__get_cpu_var(slub_free_list);
++				raw_spin_lock(&f->lock);
++				list_splice_init(&f->list, &tofree);
++				raw_spin_unlock(&f->lock);
+ 				local_irq_restore(flags);
++				free_delayed(&tofree);
+ 				oldpage = NULL;
+ 				pobjects = 0;
+ 				pages = 0;
+@@ -2079,7 +2115,22 @@
+ 
+ static void flush_all(struct kmem_cache *s)
+ {
++	LIST_HEAD(tofree);
++	int cpu;
++
+ 	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
++	for_each_online_cpu(cpu) {
++		struct slub_free_list *f;
++
++		if (!has_cpu_slab(cpu, s))
++			continue;
++
++		f = &per_cpu(slub_free_list, cpu);
++		raw_spin_lock_irq(&f->lock);
++		list_splice_init(&f->list, &tofree);
++		raw_spin_unlock_irq(&f->lock);
++		free_delayed(&tofree);
++	}
+ }
+ 
+ /*
+@@ -2115,10 +2166,10 @@
+ 	unsigned long x = 0;
+ 	struct page *page;
+ 
+-	spin_lock_irqsave(&n->list_lock, flags);
++	raw_spin_lock_irqsave(&n->list_lock, flags);
+ 	list_for_each_entry(page, &n->partial, lru)
+ 		x += get_count(page);
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	return x;
+ }
+ #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
+@@ -2255,9 +2306,11 @@
+ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ 			  unsigned long addr, struct kmem_cache_cpu *c)
+ {
++	struct slub_free_list *f;
+ 	void *freelist;
+ 	struct page *page;
+ 	unsigned long flags;
++	LIST_HEAD(tofree);
+ 
+ 	local_irq_save(flags);
+ #ifdef CONFIG_PREEMPT
+@@ -2325,7 +2378,13 @@
+ 	VM_BUG_ON(!c->page->frozen);
+ 	c->freelist = get_freepointer(s, freelist);
+ 	c->tid = next_tid(c->tid);
++out:
++	f = &__get_cpu_var(slub_free_list);
++	raw_spin_lock(&f->lock);
++	list_splice_init(&f->list, &tofree);
++	raw_spin_unlock(&f->lock);
+ 	local_irq_restore(flags);
++	free_delayed(&tofree);
+ 	return freelist;
+ 
+ new_slab:
+@@ -2342,8 +2401,7 @@
+ 
+ 	if (unlikely(!freelist)) {
+ 		slab_out_of_memory(s, gfpflags, node);
+-		local_irq_restore(flags);
+-		return NULL;
++		goto out;
+ 	}
+ 
+ 	page = c->page;
+@@ -2358,8 +2416,7 @@
+ 	deactivate_slab(s, page, get_freepointer(s, freelist));
+ 	c->page = NULL;
+ 	c->freelist = NULL;
+-	local_irq_restore(flags);
+-	return freelist;
++	goto out;
+ }
+ 
+ /*
+@@ -2444,6 +2501,10 @@
+ 
+ 	if (unlikely(gfpflags & __GFP_ZERO) && object)
+ 		memset(object, 0, s->object_size);
++#ifdef CONFIG_PREEMPT_RT_FULL
++	if (unlikely(s->ctor) && object)
++		s->ctor(object);
++#endif
+ 
+ 	slab_post_alloc_hook(s, gfpflags, object);
+ 
+@@ -2531,7 +2592,7 @@
+ 
+ 	do {
+ 		if (unlikely(n)) {
+-			spin_unlock_irqrestore(&n->list_lock, flags);
++			raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 			n = NULL;
+ 		}
+ 		prior = page->freelist;
+@@ -2563,7 +2624,7 @@
+ 				 * Otherwise the list_lock will synchronize with
+ 				 * other processors updating the list of slabs.
+ 				 */
+-				spin_lock_irqsave(&n->list_lock, flags);
++				raw_spin_lock_irqsave(&n->list_lock, flags);
+ 
+ 			}
+ 		}
+@@ -2605,7 +2666,7 @@
+ 		add_partial(n, page, DEACTIVATE_TO_TAIL);
+ 		stat(s, FREE_ADD_PARTIAL);
+ 	}
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	return;
+ 
+ slab_empty:
+@@ -2620,7 +2681,7 @@
+ 		remove_full(s, n, page);
+ 	}
+ 
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	stat(s, FREE_SLAB);
+ 	discard_slab(s, page);
+ }
+@@ -2816,7 +2877,7 @@
+ init_kmem_cache_node(struct kmem_cache_node *n)
+ {
+ 	n->nr_partial = 0;
+-	spin_lock_init(&n->list_lock);
++	raw_spin_lock_init(&n->list_lock);
+ 	INIT_LIST_HEAD(&n->partial);
+ #ifdef CONFIG_SLUB_DEBUG
+ 	atomic_long_set(&n->nr_slabs, 0);
+@@ -3373,7 +3434,7 @@
+ 		for (i = 0; i < objects; i++)
+ 			INIT_LIST_HEAD(slabs_by_inuse + i);
+ 
+-		spin_lock_irqsave(&n->list_lock, flags);
++		raw_spin_lock_irqsave(&n->list_lock, flags);
+ 
+ 		/*
+ 		 * Build lists indexed by the items in use in each slab.
+@@ -3394,7 +3455,7 @@
+ 		for (i = objects - 1; i > 0; i--)
+ 			list_splice(slabs_by_inuse + i, n->partial.prev);
+ 
+-		spin_unlock_irqrestore(&n->list_lock, flags);
++		raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 
+ 		/* Release empty slabs */
+ 		list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
+@@ -3567,6 +3628,12 @@
+ {
+ 	static __initdata struct kmem_cache boot_kmem_cache,
+ 		boot_kmem_cache_node;
++	int cpu;
++
++	for_each_possible_cpu(cpu) {
++		raw_spin_lock_init(&per_cpu(slub_free_list, cpu).lock);
++		INIT_LIST_HEAD(&per_cpu(slub_free_list, cpu).list);
++	}
+ 
+ 	if (debug_guardpage_minorder())
+ 		slub_max_order = 0;
+@@ -3815,7 +3882,7 @@
+ 	struct page *page;
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&n->list_lock, flags);
++	raw_spin_lock_irqsave(&n->list_lock, flags);
+ 
+ 	list_for_each_entry(page, &n->partial, lru) {
+ 		validate_slab_slab(s, page, map);
+@@ -3837,7 +3904,7 @@
+ 		       s->name, count, atomic_long_read(&n->nr_slabs));
+ 
+ out:
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	return count;
+ }
+ 
+@@ -4025,12 +4092,12 @@
+ 		if (!atomic_long_read(&n->nr_slabs))
+ 			continue;
+ 
+-		spin_lock_irqsave(&n->list_lock, flags);
++		raw_spin_lock_irqsave(&n->list_lock, flags);
+ 		list_for_each_entry(page, &n->partial, lru)
+ 			process_slab(&t, s, page, alloc, map);
+ 		list_for_each_entry(page, &n->full, lru)
+ 			process_slab(&t, s, page, alloc, map);
+-		spin_unlock_irqrestore(&n->list_lock, flags);
++		raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	}
+ 
+ 	for (i = 0; i < t.count; i++) {
+diff -Nur linux-3.18.8.orig/mm/swap.c linux-3.18.8/mm/swap.c
+--- linux-3.18.8.orig/mm/swap.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/swap.c	2015-03-03 08:05:18.000000000 +0100
+@@ -31,6 +31,7 @@
+ #include <linux/memcontrol.h>
+ #include <linux/gfp.h>
+ #include <linux/uio.h>
++#include <linux/locallock.h>
+ 
+ #include "internal.h"
+ 
+@@ -44,6 +45,9 @@
+ static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
+ static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
+ 
++static DEFINE_LOCAL_IRQ_LOCK(rotate_lock);
++static DEFINE_LOCAL_IRQ_LOCK(swapvec_lock);
++
+ /*
+  * This path almost never happens for VM activity - pages are normally
+  * freed via pagevecs.  But it gets used by networking.
+@@ -473,11 +477,11 @@
+ 		unsigned long flags;
+ 
+ 		page_cache_get(page);
+-		local_irq_save(flags);
++		local_lock_irqsave(rotate_lock, flags);
+ 		pvec = this_cpu_ptr(&lru_rotate_pvecs);
+ 		if (!pagevec_add(pvec, page))
+ 			pagevec_move_tail(pvec);
+-		local_irq_restore(flags);
++		local_unlock_irqrestore(rotate_lock, flags);
+ 	}
+ }
+ 
+@@ -528,12 +532,13 @@
+ void activate_page(struct page *page)
+ {
+ 	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+-		struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
++		struct pagevec *pvec = &get_locked_var(swapvec_lock,
++						       activate_page_pvecs);
+ 
+ 		page_cache_get(page);
+ 		if (!pagevec_add(pvec, page))
+ 			pagevec_lru_move_fn(pvec, __activate_page, NULL);
+-		put_cpu_var(activate_page_pvecs);
++		put_locked_var(swapvec_lock, activate_page_pvecs);
+ 	}
+ }
+ 
+@@ -559,7 +564,7 @@
+ 
+ static void __lru_cache_activate_page(struct page *page)
+ {
+-	struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
++	struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvec);
+ 	int i;
+ 
+ 	/*
+@@ -581,7 +586,7 @@
+ 		}
+ 	}
+ 
+-	put_cpu_var(lru_add_pvec);
++	put_locked_var(swapvec_lock, lru_add_pvec);
+ }
+ 
+ /*
+@@ -620,13 +625,13 @@
+ 
+ static void __lru_cache_add(struct page *page)
+ {
+-	struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
++	struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvec);
+ 
+ 	page_cache_get(page);
+ 	if (!pagevec_space(pvec))
+ 		__pagevec_lru_add(pvec);
+ 	pagevec_add(pvec, page);
+-	put_cpu_var(lru_add_pvec);
++	put_locked_var(swapvec_lock, lru_add_pvec);
+ }
+ 
+ /**
+@@ -806,9 +811,9 @@
+ 		unsigned long flags;
+ 
+ 		/* No harm done if a racing interrupt already did this */
+-		local_irq_save(flags);
++		local_lock_irqsave(rotate_lock, flags);
+ 		pagevec_move_tail(pvec);
+-		local_irq_restore(flags);
++		local_unlock_irqrestore(rotate_lock, flags);
+ 	}
+ 
+ 	pvec = &per_cpu(lru_deactivate_pvecs, cpu);
+@@ -836,18 +841,19 @@
+ 		return;
+ 
+ 	if (likely(get_page_unless_zero(page))) {
+-		struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
++		struct pagevec *pvec = &get_locked_var(swapvec_lock,
++						       lru_deactivate_pvecs);
+ 
+ 		if (!pagevec_add(pvec, page))
+ 			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
+-		put_cpu_var(lru_deactivate_pvecs);
++		put_locked_var(swapvec_lock, lru_deactivate_pvecs);
+ 	}
+ }
+ 
+ void lru_add_drain(void)
+ {
+-	lru_add_drain_cpu(get_cpu());
+-	put_cpu();
++	lru_add_drain_cpu(local_lock_cpu(swapvec_lock));
++	local_unlock_cpu(swapvec_lock);
+ }
+ 
+ static void lru_add_drain_per_cpu(struct work_struct *dummy)
+diff -Nur linux-3.18.8.orig/mm/truncate.c linux-3.18.8/mm/truncate.c
+--- linux-3.18.8.orig/mm/truncate.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/truncate.c	2015-03-03 08:05:18.000000000 +0100
+@@ -56,8 +56,11 @@
+ 	 * protected by mapping->tree_lock.
+ 	 */
+ 	if (!workingset_node_shadows(node) &&
+-	    !list_empty(&node->private_list))
+-		list_lru_del(&workingset_shadow_nodes, &node->private_list);
++	    !list_empty(&node->private_list)) {
++		local_lock(workingset_shadow_lock);
++		list_lru_del(&__workingset_shadow_nodes, &node->private_list);
++		local_unlock(workingset_shadow_lock);
++	}
+ 	__radix_tree_delete_node(&mapping->page_tree, node);
+ unlock:
+ 	spin_unlock_irq(&mapping->tree_lock);
+diff -Nur linux-3.18.8.orig/mm/vmalloc.c linux-3.18.8/mm/vmalloc.c
+--- linux-3.18.8.orig/mm/vmalloc.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/vmalloc.c	2015-03-03 08:05:18.000000000 +0100
+@@ -798,7 +798,7 @@
+ 	struct vmap_block *vb;
+ 	struct vmap_area *va;
+ 	unsigned long vb_idx;
+-	int node, err;
++	int node, err, cpu;
+ 
+ 	node = numa_node_id();
+ 
+@@ -836,11 +836,12 @@
+ 	BUG_ON(err);
+ 	radix_tree_preload_end();
+ 
+-	vbq = &get_cpu_var(vmap_block_queue);
++	cpu = get_cpu_light();
++	vbq = &__get_cpu_var(vmap_block_queue);
+ 	spin_lock(&vbq->lock);
+ 	list_add_rcu(&vb->free_list, &vbq->free);
+ 	spin_unlock(&vbq->lock);
+-	put_cpu_var(vmap_block_queue);
++	put_cpu_light();
+ 
+ 	return vb;
+ }
+@@ -908,6 +909,7 @@
+ 	struct vmap_block *vb;
+ 	unsigned long addr = 0;
+ 	unsigned int order;
++	int cpu = 0;
+ 
+ 	BUG_ON(size & ~PAGE_MASK);
+ 	BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
+@@ -923,7 +925,8 @@
+ 
+ again:
+ 	rcu_read_lock();
+-	vbq = &get_cpu_var(vmap_block_queue);
++	cpu = get_cpu_light();
++	vbq = &__get_cpu_var(vmap_block_queue);
+ 	list_for_each_entry_rcu(vb, &vbq->free, free_list) {
+ 		int i;
+ 
+@@ -947,7 +950,7 @@
+ 		spin_unlock(&vb->lock);
+ 	}
+ 
+-	put_cpu_var(vmap_block_queue);
++	put_cpu_light();
+ 	rcu_read_unlock();
+ 
+ 	if (!addr) {
+diff -Nur linux-3.18.8.orig/mm/vmstat.c linux-3.18.8/mm/vmstat.c
+--- linux-3.18.8.orig/mm/vmstat.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/vmstat.c	2015-03-03 08:05:18.000000000 +0100
+@@ -221,6 +221,7 @@
+ 	long x;
+ 	long t;
+ 
++	preempt_disable_rt();
+ 	x = delta + __this_cpu_read(*p);
+ 
+ 	t = __this_cpu_read(pcp->stat_threshold);
+@@ -230,6 +231,7 @@
+ 		x = 0;
+ 	}
+ 	__this_cpu_write(*p, x);
++	preempt_enable_rt();
+ }
+ EXPORT_SYMBOL(__mod_zone_page_state);
+ 
+@@ -262,6 +264,7 @@
+ 	s8 __percpu *p = pcp->vm_stat_diff + item;
+ 	s8 v, t;
+ 
++	preempt_disable_rt();
+ 	v = __this_cpu_inc_return(*p);
+ 	t = __this_cpu_read(pcp->stat_threshold);
+ 	if (unlikely(v > t)) {
+@@ -270,6 +273,7 @@
+ 		zone_page_state_add(v + overstep, zone, item);
+ 		__this_cpu_write(*p, -overstep);
+ 	}
++	preempt_enable_rt();
+ }
+ 
+ void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
+@@ -284,6 +288,7 @@
+ 	s8 __percpu *p = pcp->vm_stat_diff + item;
+ 	s8 v, t;
+ 
++	preempt_disable_rt();
+ 	v = __this_cpu_dec_return(*p);
+ 	t = __this_cpu_read(pcp->stat_threshold);
+ 	if (unlikely(v < - t)) {
+@@ -292,6 +297,7 @@
+ 		zone_page_state_add(v - overstep, zone, item);
+ 		__this_cpu_write(*p, overstep);
+ 	}
++	preempt_enable_rt();
+ }
+ 
+ void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
+diff -Nur linux-3.18.8.orig/mm/workingset.c linux-3.18.8/mm/workingset.c
+--- linux-3.18.8.orig/mm/workingset.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/mm/workingset.c	2015-03-03 08:05:18.000000000 +0100
+@@ -264,7 +264,8 @@
+  * point where they would still be useful.
+  */
+ 
+-struct list_lru workingset_shadow_nodes;
++struct list_lru __workingset_shadow_nodes;
++DEFINE_LOCAL_IRQ_LOCK(workingset_shadow_lock);
+ 
+ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
+ 					struct shrink_control *sc)
+@@ -274,9 +275,9 @@
+ 	unsigned long pages;
+ 
+ 	/* list_lru lock nests inside IRQ-safe mapping->tree_lock */
+-	local_irq_disable();
+-	shadow_nodes = list_lru_count_node(&workingset_shadow_nodes, sc->nid);
+-	local_irq_enable();
++	local_lock_irq(workingset_shadow_lock);
++	shadow_nodes = list_lru_count_node(&__workingset_shadow_nodes, sc->nid);
++	local_unlock_irq(workingset_shadow_lock);
+ 
+ 	pages = node_present_pages(sc->nid);
+ 	/*
+@@ -362,9 +363,9 @@
+ 	spin_unlock(&mapping->tree_lock);
+ 	ret = LRU_REMOVED_RETRY;
+ out:
+-	local_irq_enable();
++	local_unlock_irq(workingset_shadow_lock);
+ 	cond_resched();
+-	local_irq_disable();
++	local_lock_irq(workingset_shadow_lock);
+ 	spin_lock(lru_lock);
+ 	return ret;
+ }
+@@ -375,10 +376,10 @@
+ 	unsigned long ret;
+ 
+ 	/* list_lru lock nests inside IRQ-safe mapping->tree_lock */
+-	local_irq_disable();
+-	ret =  list_lru_walk_node(&workingset_shadow_nodes, sc->nid,
++	local_lock_irq(workingset_shadow_lock);
++	ret =  list_lru_walk_node(&__workingset_shadow_nodes, sc->nid,
+ 				  shadow_lru_isolate, NULL, &sc->nr_to_scan);
+-	local_irq_enable();
++	local_unlock_irq(workingset_shadow_lock);
+ 	return ret;
+ }
+ 
+@@ -399,7 +400,7 @@
+ {
+ 	int ret;
+ 
+-	ret = list_lru_init_key(&workingset_shadow_nodes, &shadow_nodes_key);
++	ret = list_lru_init_key(&__workingset_shadow_nodes, &shadow_nodes_key);
+ 	if (ret)
+ 		goto err;
+ 	ret = register_shrinker(&workingset_shadow_shrinker);
+@@ -407,7 +408,7 @@
+ 		goto err_list_lru;
+ 	return 0;
+ err_list_lru:
+-	list_lru_destroy(&workingset_shadow_nodes);
++	list_lru_destroy(&__workingset_shadow_nodes);
+ err:
+ 	return ret;
+ }
+diff -Nur linux-3.18.8.orig/net/core/dev.c linux-3.18.8/net/core/dev.c
+--- linux-3.18.8.orig/net/core/dev.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/core/dev.c	2015-03-03 08:05:18.000000000 +0100
+@@ -182,6 +182,7 @@
+ static DEFINE_HASHTABLE(napi_hash, 8);
+ 
+ static seqcount_t devnet_rename_seq;
++static DEFINE_MUTEX(devnet_rename_mutex);
+ 
+ static inline void dev_base_seq_inc(struct net *net)
+ {
+@@ -203,14 +204,14 @@
+ static inline void rps_lock(struct softnet_data *sd)
+ {
+ #ifdef CONFIG_RPS
+-	spin_lock(&sd->input_pkt_queue.lock);
++	raw_spin_lock(&sd->input_pkt_queue.raw_lock);
+ #endif
+ }
+ 
+ static inline void rps_unlock(struct softnet_data *sd)
+ {
+ #ifdef CONFIG_RPS
+-	spin_unlock(&sd->input_pkt_queue.lock);
++	raw_spin_unlock(&sd->input_pkt_queue.raw_lock);
+ #endif
+ }
+ 
+@@ -832,7 +833,8 @@
+ 	strcpy(name, dev->name);
+ 	rcu_read_unlock();
+ 	if (read_seqcount_retry(&devnet_rename_seq, seq)) {
+-		cond_resched();
++		mutex_lock(&devnet_rename_mutex);
++		mutex_unlock(&devnet_rename_mutex);
+ 		goto retry;
+ 	}
+ 
+@@ -1101,20 +1103,17 @@
+ 	if (dev->flags & IFF_UP)
+ 		return -EBUSY;
+ 
+-	write_seqcount_begin(&devnet_rename_seq);
++	mutex_lock(&devnet_rename_mutex);
++	__raw_write_seqcount_begin(&devnet_rename_seq);
+ 
+-	if (strncmp(newname, dev->name, IFNAMSIZ) == 0) {
+-		write_seqcount_end(&devnet_rename_seq);
+-		return 0;
+-	}
++	if (strncmp(newname, dev->name, IFNAMSIZ) == 0)
++		goto outunlock;
+ 
+ 	memcpy(oldname, dev->name, IFNAMSIZ);
+ 
+ 	err = dev_get_valid_name(net, dev, newname);
+-	if (err < 0) {
+-		write_seqcount_end(&devnet_rename_seq);
+-		return err;
+-	}
++	if (err < 0)
++		goto outunlock;
+ 
+ 	if (oldname[0] && !strchr(oldname, '%'))
+ 		netdev_info(dev, "renamed from %s\n", oldname);
+@@ -1127,11 +1126,12 @@
+ 	if (ret) {
+ 		memcpy(dev->name, oldname, IFNAMSIZ);
+ 		dev->name_assign_type = old_assign_type;
+-		write_seqcount_end(&devnet_rename_seq);
+-		return ret;
++		err = ret;
++		goto outunlock;
+ 	}
+ 
+-	write_seqcount_end(&devnet_rename_seq);
++	__raw_write_seqcount_end(&devnet_rename_seq);
++	mutex_unlock(&devnet_rename_mutex);
+ 
+ 	netdev_adjacent_rename_links(dev, oldname);
+ 
+@@ -1152,7 +1152,8 @@
+ 		/* err >= 0 after dev_alloc_name() or stores the first errno */
+ 		if (err >= 0) {
+ 			err = ret;
+-			write_seqcount_begin(&devnet_rename_seq);
++			mutex_lock(&devnet_rename_mutex);
++			__raw_write_seqcount_begin(&devnet_rename_seq);
+ 			memcpy(dev->name, oldname, IFNAMSIZ);
+ 			memcpy(oldname, newname, IFNAMSIZ);
+ 			dev->name_assign_type = old_assign_type;
+@@ -1165,6 +1166,11 @@
+ 	}
+ 
+ 	return err;
++
++outunlock:
++	__raw_write_seqcount_end(&devnet_rename_seq);
++	mutex_unlock(&devnet_rename_mutex);
++	return err;
+ }
+ 
+ /**
+@@ -2160,6 +2166,7 @@
+ 	sd->output_queue_tailp = &q->next_sched;
+ 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ 
+ void __netif_schedule(struct Qdisc *q)
+@@ -2241,6 +2248,7 @@
+ 	__this_cpu_write(softnet_data.completion_queue, skb);
+ 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(__dev_kfree_skb_irq);
+ 
+@@ -3336,6 +3344,7 @@
+ 	rps_unlock(sd);
+ 
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ 
+ 	atomic_long_inc(&skb->dev->rx_dropped);
+ 	kfree_skb(skb);
+@@ -3354,7 +3363,7 @@
+ 		struct rps_dev_flow voidflow, *rflow = &voidflow;
+ 		int cpu;
+ 
+-		preempt_disable();
++		migrate_disable();
+ 		rcu_read_lock();
+ 
+ 		cpu = get_rps_cpu(skb->dev, skb, &rflow);
+@@ -3364,13 +3373,13 @@
+ 		ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
+ 
+ 		rcu_read_unlock();
+-		preempt_enable();
++		migrate_enable();
+ 	} else
+ #endif
+ 	{
+ 		unsigned int qtail;
+-		ret = enqueue_to_backlog(skb, get_cpu(), &qtail);
+-		put_cpu();
++		ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail);
++		put_cpu_light();
+ 	}
+ 	return ret;
+ }
+@@ -3404,16 +3413,44 @@
+ 
+ 	trace_netif_rx_ni_entry(skb);
+ 
+-	preempt_disable();
++	local_bh_disable();
+ 	err = netif_rx_internal(skb);
+-	if (local_softirq_pending())
+-		do_softirq();
+-	preempt_enable();
++	local_bh_enable();
+ 
+ 	return err;
+ }
+ EXPORT_SYMBOL(netif_rx_ni);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++/*
++ * RT runs ksoftirqd as a real time thread and the root_lock is a
++ * "sleeping spinlock". If the trylock fails then we can go into an
++ * infinite loop when ksoftirqd preempted the task which actually
++ * holds the lock, because we requeue q and raise NET_TX softirq
++ * causing ksoftirqd to loop forever.
++ *
++ * It's safe to use spin_lock on RT here as softirqs run in thread
++ * context and cannot deadlock against the thread which is holding
++ * root_lock.
++ *
++ * On !RT the trylock might fail, but there we bail out from the
++ * softirq loop after 10 attempts which we can't do on RT. And the
++ * task holding root_lock cannot be preempted, so the only downside of
++ * that trylock is that we need 10 loops to decide that we should have
++ * given up in the first one :)
++ */
++static inline int take_root_lock(spinlock_t *lock)
++{
++	spin_lock(lock);
++	return 1;
++}
++#else
++static inline int take_root_lock(spinlock_t *lock)
++{
++	return spin_trylock(lock);
++}
++#endif
++
+ static void net_tx_action(struct softirq_action *h)
+ {
+ 	struct softnet_data *sd = this_cpu_ptr(&softnet_data);
+@@ -3455,7 +3492,7 @@
+ 			head = head->next_sched;
+ 
+ 			root_lock = qdisc_lock(q);
+-			if (spin_trylock(root_lock)) {
++			if (take_root_lock(root_lock)) {
+ 				smp_mb__before_atomic();
+ 				clear_bit(__QDISC_STATE_SCHED,
+ 					  &q->state);
+@@ -3848,7 +3885,7 @@
+ 	skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) {
+ 		if (skb->dev == dev) {
+ 			__skb_unlink(skb, &sd->input_pkt_queue);
+-			kfree_skb(skb);
++			__skb_queue_tail(&sd->tofree_queue, skb);
+ 			input_queue_head_incr(sd);
+ 		}
+ 	}
+@@ -3857,10 +3894,13 @@
+ 	skb_queue_walk_safe(&sd->process_queue, skb, tmp) {
+ 		if (skb->dev == dev) {
+ 			__skb_unlink(skb, &sd->process_queue);
+-			kfree_skb(skb);
++			__skb_queue_tail(&sd->tofree_queue, skb);
+ 			input_queue_head_incr(sd);
+ 		}
+ 	}
++
++	if (!skb_queue_empty(&sd->tofree_queue))
++		raise_softirq_irqoff(NET_RX_SOFTIRQ);
+ }
+ 
+ static int napi_gro_complete(struct sk_buff *skb)
+@@ -4323,6 +4363,7 @@
+ 	} else
+ #endif
+ 		local_irq_enable();
++	preempt_check_resched_rt();
+ }
+ 
+ static int process_backlog(struct napi_struct *napi, int quota)
+@@ -4394,6 +4435,7 @@
+ 	local_irq_save(flags);
+ 	____napi_schedule(this_cpu_ptr(&softnet_data), n);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(__napi_schedule);
+ 
+@@ -4516,10 +4558,17 @@
+ 	struct softnet_data *sd = this_cpu_ptr(&softnet_data);
+ 	unsigned long time_limit = jiffies + 2;
+ 	int budget = netdev_budget;
++	struct sk_buff *skb;
+ 	void *have;
+ 
+ 	local_irq_disable();
+ 
++	while ((skb = __skb_dequeue(&sd->tofree_queue))) {
++		local_irq_enable();
++		kfree_skb(skb);
++		local_irq_disable();
++	}
++
+ 	while (!list_empty(&sd->poll_list)) {
+ 		struct napi_struct *n;
+ 		int work, weight;
+@@ -7008,6 +7057,7 @@
+ 
+ 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
+ 	local_irq_enable();
++	preempt_check_resched_rt();
+ 
+ 	/* Process offline CPU's input_pkt_queue */
+ 	while ((skb = __skb_dequeue(&oldsd->process_queue))) {
+@@ -7018,6 +7068,9 @@
+ 		netif_rx_internal(skb);
+ 		input_queue_head_incr(oldsd);
+ 	}
++	while ((skb = __skb_dequeue(&oldsd->tofree_queue))) {
++		kfree_skb(skb);
++	}
+ 
+ 	return NOTIFY_OK;
+ }
+@@ -7319,8 +7372,9 @@
+ 	for_each_possible_cpu(i) {
+ 		struct softnet_data *sd = &per_cpu(softnet_data, i);
+ 
+-		skb_queue_head_init(&sd->input_pkt_queue);
+-		skb_queue_head_init(&sd->process_queue);
++		skb_queue_head_init_raw(&sd->input_pkt_queue);
++		skb_queue_head_init_raw(&sd->process_queue);
++		skb_queue_head_init_raw(&sd->tofree_queue);
+ 		INIT_LIST_HEAD(&sd->poll_list);
+ 		sd->output_queue_tailp = &sd->output_queue;
+ #ifdef CONFIG_RPS
+diff -Nur linux-3.18.8.orig/net/core/skbuff.c linux-3.18.8/net/core/skbuff.c
+--- linux-3.18.8.orig/net/core/skbuff.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/core/skbuff.c	2015-03-03 08:05:18.000000000 +0100
+@@ -63,6 +63,7 @@
+ #include <linux/errqueue.h>
+ #include <linux/prefetch.h>
+ #include <linux/if_vlan.h>
++#include <linux/locallock.h>
+ 
+ #include <net/protocol.h>
+ #include <net/dst.h>
+@@ -336,6 +337,7 @@
+ 	unsigned int		pagecnt_bias;
+ };
+ static DEFINE_PER_CPU(struct netdev_alloc_cache, netdev_alloc_cache);
++static DEFINE_LOCAL_IRQ_LOCK(netdev_alloc_lock);
+ 
+ static void *__netdev_alloc_frag(unsigned int fragsz, gfp_t gfp_mask)
+ {
+@@ -344,7 +346,7 @@
+ 	int order;
+ 	unsigned long flags;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(netdev_alloc_lock, flags);
+ 	nc = this_cpu_ptr(&netdev_alloc_cache);
+ 	if (unlikely(!nc->frag.page)) {
+ refill:
+@@ -389,7 +391,7 @@
+ 	nc->frag.offset += fragsz;
+ 	nc->pagecnt_bias--;
+ end:
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(netdev_alloc_lock, flags);
+ 	return data;
+ }
+ 
+diff -Nur linux-3.18.8.orig/net/core/sock.c linux-3.18.8/net/core/sock.c
+--- linux-3.18.8.orig/net/core/sock.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/core/sock.c	2015-03-03 08:05:18.000000000 +0100
+@@ -2326,12 +2326,11 @@
+ 	if (sk->sk_lock.owned)
+ 		__lock_sock(sk);
+ 	sk->sk_lock.owned = 1;
+-	spin_unlock(&sk->sk_lock.slock);
++	spin_unlock_bh(&sk->sk_lock.slock);
+ 	/*
+ 	 * The sk_lock has mutex_lock() semantics here:
+ 	 */
+ 	mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
+-	local_bh_enable();
+ }
+ EXPORT_SYMBOL(lock_sock_nested);
+ 
+diff -Nur linux-3.18.8.orig/net/ipv4/icmp.c linux-3.18.8/net/ipv4/icmp.c
+--- linux-3.18.8.orig/net/ipv4/icmp.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/ipv4/icmp.c	2015-03-03 08:05:18.000000000 +0100
+@@ -69,6 +69,7 @@
+ #include <linux/jiffies.h>
+ #include <linux/kernel.h>
+ #include <linux/fcntl.h>
++#include <linux/sysrq.h>
+ #include <linux/socket.h>
+ #include <linux/in.h>
+ #include <linux/inet.h>
+@@ -864,6 +865,30 @@
+ }
+ 
+ /*
++ * 32bit and 64bit have different timestamp length, so we check for
++ * the cookie at offset 20 and verify it is repeated at offset 50
++ */
++#define CO_POS0		20
++#define CO_POS1		50
++#define CO_SIZE		sizeof(int)
++#define ICMP_SYSRQ_SIZE	57
++
++/*
++ * We got a ICMP_SYSRQ_SIZE sized ping request. Check for the cookie
++ * pattern and if it matches send the next byte as a trigger to sysrq.
++ */
++static void icmp_check_sysrq(struct net *net, struct sk_buff *skb)
++{
++	int cookie = htonl(net->ipv4.sysctl_icmp_echo_sysrq);
++	char *p = skb->data;
++
++	if (!memcmp(&cookie, p + CO_POS0, CO_SIZE) &&
++	    !memcmp(&cookie, p + CO_POS1, CO_SIZE) &&
++	    p[CO_POS0 + CO_SIZE] == p[CO_POS1 + CO_SIZE])
++		handle_sysrq(p[CO_POS0 + CO_SIZE]);
++}
++
++/*
+  *	Handle ICMP_ECHO ("ping") requests.
+  *
+  *	RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
+@@ -890,6 +915,11 @@
+ 		icmp_param.data_len	   = skb->len;
+ 		icmp_param.head_len	   = sizeof(struct icmphdr);
+ 		icmp_reply(&icmp_param, skb);
++
++		if (skb->len == ICMP_SYSRQ_SIZE &&
++		    net->ipv4.sysctl_icmp_echo_sysrq) {
++			icmp_check_sysrq(net, skb);
++		}
+ 	}
+ }
+ 
+diff -Nur linux-3.18.8.orig/net/ipv4/ip_output.c linux-3.18.8/net/ipv4/ip_output.c
+--- linux-3.18.8.orig/net/ipv4/ip_output.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/ipv4/ip_output.c	2015-03-03 21:30:51.000000000 +0100
+@@ -79,6 +79,7 @@
+ #include <linux/mroute.h>
+ #include <linux/netlink.h>
+ #include <linux/tcp.h>
++#include <linux/locallock.h>
+ 
+ int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
+ EXPORT_SYMBOL(sysctl_ip_default_ttl);
+@@ -1507,6 +1508,7 @@
+  *	Generic function to send a packet as reply to another packet.
+  *	Used to send some TCP resets/acks so far.
+  */
++
+ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
+ 			   const struct ip_options *sopt,
+ 			   __be32 daddr, __be32 saddr,
+diff -Nur linux-3.18.8.orig/net/ipv4/sysctl_net_ipv4.c linux-3.18.8/net/ipv4/sysctl_net_ipv4.c
+--- linux-3.18.8.orig/net/ipv4/sysctl_net_ipv4.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/ipv4/sysctl_net_ipv4.c	2015-03-03 08:05:18.000000000 +0100
+@@ -779,6 +779,13 @@
+ 		.proc_handler	= proc_dointvec
+ 	},
+ 	{
++		.procname	= "icmp_echo_sysrq",
++		.data		= &init_net.ipv4.sysctl_icmp_echo_sysrq,
++		.maxlen		= sizeof(int),
++		.mode		= 0644,
++		.proc_handler	= proc_dointvec
++	},
++	{
+ 		.procname	= "icmp_ignore_bogus_error_responses",
+ 		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
+ 		.maxlen		= sizeof(int),
+diff -Nur linux-3.18.8.orig/net/mac80211/rx.c linux-3.18.8/net/mac80211/rx.c
+--- linux-3.18.8.orig/net/mac80211/rx.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/mac80211/rx.c	2015-03-03 08:05:18.000000000 +0100
+@@ -3356,7 +3356,7 @@
+ 	struct ieee80211_supported_band *sband;
+ 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+ 
+-	WARN_ON_ONCE(softirq_count() == 0);
++	WARN_ON_ONCE_NONRT(softirq_count() == 0);
+ 
+ 	if (WARN_ON(status->band >= IEEE80211_NUM_BANDS))
+ 		goto drop;
+diff -Nur linux-3.18.8.orig/net/netfilter/core.c linux-3.18.8/net/netfilter/core.c
+--- linux-3.18.8.orig/net/netfilter/core.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/netfilter/core.c	2015-03-03 08:05:18.000000000 +0100
+@@ -21,11 +21,17 @@
+ #include <linux/proc_fs.h>
+ #include <linux/mutex.h>
+ #include <linux/slab.h>
++#include <linux/locallock.h>
+ #include <net/net_namespace.h>
+ #include <net/sock.h>
+ 
+ #include "nf_internals.h"
+ 
++#ifdef CONFIG_PREEMPT_RT_BASE
++DEFINE_LOCAL_IRQ_LOCK(xt_write_lock);
++EXPORT_PER_CPU_SYMBOL(xt_write_lock);
++#endif
++
+ static DEFINE_MUTEX(afinfo_mutex);
+ 
+ const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly;
+diff -Nur linux-3.18.8.orig/net/packet/af_packet.c linux-3.18.8/net/packet/af_packet.c
+--- linux-3.18.8.orig/net/packet/af_packet.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/packet/af_packet.c	2015-03-03 08:05:18.000000000 +0100
+@@ -63,6 +63,7 @@
+ #include <linux/if_packet.h>
+ #include <linux/wireless.h>
+ #include <linux/kernel.h>
++#include <linux/delay.h>
+ #include <linux/kmod.h>
+ #include <linux/slab.h>
+ #include <linux/vmalloc.h>
+@@ -692,7 +693,7 @@
+ 	if (BLOCK_NUM_PKTS(pbd)) {
+ 		while (atomic_read(&pkc->blk_fill_in_prog)) {
+ 			/* Waiting for skb_copy_bits to finish... */
+-			cpu_relax();
++			cpu_chill();
+ 		}
+ 	}
+ 
+@@ -943,7 +944,7 @@
+ 		if (!(status & TP_STATUS_BLK_TMO)) {
+ 			while (atomic_read(&pkc->blk_fill_in_prog)) {
+ 				/* Waiting for skb_copy_bits to finish... */
+-				cpu_relax();
++				cpu_chill();
+ 			}
+ 		}
+ 		prb_close_block(pkc, pbd, po, status);
+diff -Nur linux-3.18.8.orig/net/rds/ib_rdma.c linux-3.18.8/net/rds/ib_rdma.c
+--- linux-3.18.8.orig/net/rds/ib_rdma.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/rds/ib_rdma.c	2015-03-03 08:05:18.000000000 +0100
+@@ -34,6 +34,7 @@
+ #include <linux/slab.h>
+ #include <linux/rculist.h>
+ #include <linux/llist.h>
++#include <linux/delay.h>
+ 
+ #include "rds.h"
+ #include "ib.h"
+@@ -286,7 +287,7 @@
+ 	for_each_online_cpu(cpu) {
+ 		flag = &per_cpu(clean_list_grace, cpu);
+ 		while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
+-			cpu_relax();
++			cpu_chill();
+ 	}
+ }
+ 
+diff -Nur linux-3.18.8.orig/net/sched/sch_generic.c linux-3.18.8/net/sched/sch_generic.c
+--- linux-3.18.8.orig/net/sched/sch_generic.c	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/net/sched/sch_generic.c	2015-03-03 08:05:18.000000000 +0100
+@@ -894,7 +894,7 @@
+ 	/* Wait for outstanding qdisc_run calls. */
+ 	list_for_each_entry(dev, head, close_list)
+ 		while (some_qdisc_is_busy(dev))
+-			yield();
++			msleep(1);
+ }
+ 
+ void dev_deactivate(struct net_device *dev)
+diff -Nur linux-3.18.8.orig/scripts/mkcompile_h linux-3.18.8/scripts/mkcompile_h
+--- linux-3.18.8.orig/scripts/mkcompile_h	2015-02-27 02:49:36.000000000 +0100
++++ linux-3.18.8/scripts/mkcompile_h	2015-03-03 08:05:18.000000000 +0100
+@@ -4,7 +4,8 @@
+ ARCH=$2
+ SMP=$3
+ PREEMPT=$4
+-CC=$5
++RT=$5
++CC=$6
+ 
+ vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
+ 
+@@ -57,6 +58,7 @@
+ CONFIG_FLAGS=""
+ if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
+ if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
++if [ -n "$RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS RT"; fi
+ UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"
+ 
+ # Truncate to maximum length

toolchain/kernel-headers/Makefile

@@ -61,6 +61,11 @@ ifeq ($(ADK_KERNEL_ADDON_DIETNET),y)
 	$(TRACE) dietnet-kernel-patch
 	$(PATCH) $(TOOLCHAIN_BUILD_DIR)/w-$(PKG_NAME)-$(PKG_VERSION)-$(PKG_RELEASE)/linux-$(KERNEL_VERSION) \
 		$(ADK_TOPDIR)/target/linux/patches/$(KERNEL_VERSION) patch-dietnet $(MAKE_TRACE)
+endif
+ifeq ($(ADK_KERNEL_ADDON_LINUXRT),y)
+	$(TRACE) linux-rt-kernel-patch
+	$(PATCH) $(TOOLCHAIN_BUILD_DIR)/w-$(PKG_NAME)-$(PKG_VERSION)-$(PKG_RELEASE)/linux-$(KERNEL_VERSION) \
+		$(ADK_TOPDIR)/target/linux/patches/$(KERNEL_VERSION) patch-linuxrt $(MAKE_TRACE)
 endif
 	touch $@