Linux-libre 4.5.1-gnupck-4.5.1-gnu

7 files changed, 7820 insertions, 3 deletions

diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 7d4cba227..15e398808 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -11,11 +11,16 @@ ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
 CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
 endif
 
+ifdef CONFIG_SCHED_BFS
+obj-y += bfs.o clock.o
+else
 obj-y += core.o loadavg.o clock.o cputime.o
 obj-y += idle_task.o fair.o rt.o deadline.o stop_task.o
-obj-y += wait.o swait.o completion.o idle.o
-obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o
+obj-$(CONFIG_SMP) += cpudeadline.o
 obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
-obj-$(CONFIG_SCHEDSTATS) += stats.o
 obj-$(CONFIG_SCHED_DEBUG) += debug.o
 obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
+endif
+obj-y += wait.o swait.o completion.o idle.o
+obj-$(CONFIG_SMP) += cpupri.o
+obj-$(CONFIG_SCHEDSTATS) += stats.o
diff --git a/kernel/sched/bfs.c b/kernel/sched/bfs.c
new file mode 100644
index 000000000..698007a9f
--- /dev/null
+++ b/kernel/sched/bfs.c
@@ -0,0 +1,7609 @@
+/*
+ *  kernel/sched/bfs.c, was kernel/sched.c
+ *
+ *  Kernel scheduler and related syscalls
+ *
+ *  Copyright (C) 1991-2002  Linus Torvalds
+ *
+ *  1996-12-23  Modified by Dave Grothe to fix bugs in semaphores and
+ *		make semaphores SMP safe
+ *  1998-11-19	Implemented schedule_timeout() and related stuff
+ *		by Andrea Arcangeli
+ *  2002-01-04	New ultra-scalable O(1) scheduler by Ingo Molnar:
+ *		hybrid priority-list and round-robin design with
+ *		an array-switch method of distributing timeslices
+ *		and per-CPU runqueues.  Cleanups and useful suggestions
+ *		by Davide Libenzi, preemptible kernel bits by Robert Love.
+ *  2003-09-03	Interactivity tuning by Con Kolivas.
+ *  2004-04-02	Scheduler domains code by Nick Piggin
+ *  2007-04-15  Work begun on replacing all interactivity tuning with a
+ *              fair scheduling design by Con Kolivas.
+ *  2007-05-05  Load balancing (smp-nice) and other improvements
+ *              by Peter Williams
+ *  2007-05-06  Interactivity improvements to CFS by Mike Galbraith
+ *  2007-07-01  Group scheduling enhancements by Srivatsa Vaddagiri
+ *  2007-11-29  RT balancing improvements by Steven Rostedt, Gregory Haskins,
+ *              Thomas Gleixner, Mike Kravetz
+ *  now		Brainfuck deadline scheduling policy by Con Kolivas deletes
+ *              a whole lot of those previous things.
+ */
+
+#include <linux/kasan.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/nmi.h>
+#include <linux/init.h>
+#include <asm/uaccess.h>
+#include <linux/highmem.h>
+#include <asm/mmu_context.h>
+#include <linux/interrupt.h>
+#include <linux/capability.h>
+#include <linux/completion.h>
+#include <linux/kernel_stat.h>
+#include <linux/debug_locks.h>
+#include <linux/perf_event.h>
+#include <linux/security.h>
+#include <linux/notifier.h>
+#include <linux/profile.h>
+#include <linux/freezer.h>
+#include <linux/vmalloc.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/smp.h>
+#include <linux/threads.h>
+#include <linux/timer.h>
+#include <linux/rcupdate.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/cpumask.h>
+#include <linux/percpu.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/sched/sysctl.h>
+#include <linux/times.h>
+#include <linux/tsacct_kern.h>
+#include <linux/kprobes.h>
+#include <linux/delayacct.h>
+#include <linux/log2.h>
+#include <linux/bootmem.h>
+#include <linux/ftrace.h>
+#include <linux/slab.h>
+#include <linux/init_task.h>
+#include <linux/binfmts.h>
+#include <linux/context_tracking.h>
+#include <linux/sched/prio.h>
+#include <linux/tick.h>
+
+#include <asm/irq_regs.h>
+#include <asm/switch_to.h>
+#include <asm/tlb.h>
+#include <asm/unistd.h>
+#include <asm/mutex.h>
+#ifdef CONFIG_PARAVIRT
+#include <asm/paravirt.h>
+#endif
+
+#include "cpupri.h"
+#include "../workqueue_internal.h"
+#include "../smpboot.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/sched.h>
+
+#include "bfs_sched.h"
+
+#define rt_prio(prio)		unlikely((prio) < MAX_RT_PRIO)
+#define rt_task(p)		rt_prio((p)->prio)
+#define rt_queue(rq)		rt_prio((rq)->rq_prio)
+#define batch_task(p)		(unlikely((p)->policy == SCHED_BATCH))
+#define is_rt_policy(policy)	((policy) == SCHED_FIFO || \
+					(policy) == SCHED_RR)
+#define has_rt_policy(p)	unlikely(is_rt_policy((p)->policy))
+
+#define is_idle_policy(policy)	((policy) == SCHED_IDLEPRIO)
+#define idleprio_task(p)	unlikely(is_idle_policy((p)->policy))
+#define task_running_idle(p)	unlikely((p)->prio == IDLE_PRIO)
+#define idle_queue(rq)		(unlikely(is_idle_policy((rq)->rq_policy)))
+
+#define is_iso_policy(policy)	((policy) == SCHED_ISO)
+#define iso_task(p)		unlikely(is_iso_policy((p)->policy))
+#define iso_queue(rq)		unlikely(is_iso_policy((rq)->rq_policy))
+#define task_running_iso(p)	unlikely((p)->prio == ISO_PRIO)
+#define rq_running_iso(rq)	((rq)->rq_prio == ISO_PRIO)
+
+#define rq_idle(rq)		((rq)->rq_prio == PRIO_LIMIT)
+
+#define ISO_PERIOD		((5 * HZ * grq.noc) + 1)
+
+#define SCHED_PRIO(p)		((p) + MAX_RT_PRIO)
+#define STOP_PRIO		(MAX_RT_PRIO - 1)
+
+/*
+ * Some helpers for converting to/from various scales. Use shifts to get
+ * approximate multiples of ten for less overhead.
+ */
+#define JIFFIES_TO_NS(TIME)	((TIME) * (1000000000 / HZ))
+#define JIFFY_NS		(1000000000 / HZ)
+#define HALF_JIFFY_NS		(1000000000 / HZ / 2)
+#define HALF_JIFFY_US		(1000000 / HZ / 2)
+#define MS_TO_NS(TIME)		((TIME) << 20)
+#define MS_TO_US(TIME)		((TIME) << 10)
+#define NS_TO_MS(TIME)		((TIME) >> 20)
+#define NS_TO_US(TIME)		((TIME) >> 10)
+
+#define RESCHED_US	(100) /* Reschedule if less than this many μs left */
+
+void print_scheduler_version(void)
+{
+	printk(KERN_INFO "BFS CPU scheduler v0.469 by Con Kolivas.\n");
+}
+
+/*
+ * This is the time all tasks within the same priority round robin.
+ * Value is in ms and set to a minimum of 6ms. Scales with number of cpus.
+ * Tunable via /proc interface.
+ */
+#ifdef CONFIG_PCK_INTERACTIVE
+int rr_interval __read_mostly = 3;
+#else
+int rr_interval __read_mostly = 6;
+#endif
+
+/* Tunable to choose whether to prioritise latency or throughput, simple
+ * binary yes or no */
+
+int sched_interactive __read_mostly = 1;
+
+/*
+ * sched_iso_cpu - sysctl which determines the cpu percentage SCHED_ISO tasks
+ * are allowed to run five seconds as real time tasks. This is the total over
+ * all online cpus.
+ */
+#ifdef CONFIG_PCK_INTERACTIVE
+int sched_iso_cpu __read_mostly = 25;
+#else
+int sched_iso_cpu __read_mostly = 70;
+#endif
+
+/*
+ * The relative length of deadline for each priority(nice) level.
+ */
+static int prio_ratios[NICE_WIDTH] __read_mostly;
+
+/*
+ * The quota handed out to tasks of all priority levels when refilling their
+ * time_slice.
+ */
+static inline int timeslice(void)
+{
+	return MS_TO_US(rr_interval);
+}
+
+/*
+ * The global runqueue data that all CPUs work off. Data is protected either
+ * by the global grq lock, or the discrete lock that precedes the data in this
+ * struct.
+ */
+struct global_rq {
+	raw_spinlock_t lock;
+	unsigned long nr_running;
+	unsigned long nr_uninterruptible;
+	unsigned long long nr_switches;
+	struct list_head queue[PRIO_LIMIT];
+	DECLARE_BITMAP(prio_bitmap, PRIO_LIMIT + 1);
+	unsigned long qnr; /* queued not running */
+#ifdef CONFIG_SMP
+	cpumask_t cpu_idle_map;
+	bool idle_cpus;
+#endif
+	int noc; /* num_online_cpus stored and updated when it changes */
+	u64 niffies; /* Nanosecond jiffies */
+	unsigned long last_jiffy; /* Last jiffy we updated niffies */
+
+	raw_spinlock_t iso_lock;
+	int iso_ticks;
+	bool iso_refractory;
+};
+
+#ifdef CONFIG_SMP
+/*
+ * We add the notion of a root-domain which will be used to define per-domain
+ * variables. Each exclusive cpuset essentially defines an island domain by
+ * fully partitioning the member cpus from any other cpuset. Whenever a new
+ * exclusive cpuset is created, we also create and attach a new root-domain
+ * object.
+ *
+ */
+struct root_domain {
+	atomic_t refcount;
+	atomic_t rto_count;
+	struct rcu_head rcu;
+	cpumask_var_t span;
+	cpumask_var_t online;
+
+	/*
+	 * The "RT overload" flag: it gets set if a CPU has more than
+	 * one runnable RT task.
+	 */
+	cpumask_var_t rto_mask;
+	struct cpupri cpupri;
+};
+
+/*
+ * By default the system creates a single root-domain with all cpus as
+ * members (mimicking the global state we have today).
+ */
+static struct root_domain def_root_domain;
+
+#endif /* CONFIG_SMP */
+
+/* There can be only one */
+static struct global_rq grq;
+
+static DEFINE_MUTEX(sched_hotcpu_mutex);
+
+/* cpus with isolated domains */
+cpumask_var_t cpu_isolated_map;
+
+DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+#ifdef CONFIG_SMP
+struct rq *cpu_rq(int cpu)
+{
+	return &per_cpu(runqueues, (cpu));
+}
+#define task_rq(p)		cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
+/*
+ * sched_domains_mutex serialises calls to init_sched_domains,
+ * detach_destroy_domains and partition_sched_domains.
+ */
+DEFINE_MUTEX(sched_domains_mutex);
+
+/*
+ * By default the system creates a single root-domain with all cpus as
+ * members (mimicking the global state we have today).
+ */
+static struct root_domain def_root_domain;
+
+int __weak arch_sd_sibling_asym_packing(void)
+{
+       return 0*SD_ASYM_PACKING;
+}
+#else
+struct rq *uprq;
+#endif /* CONFIG_SMP */
+
+static inline void update_rq_clock(struct rq *rq);
+
+/*
+ * Sanity check should sched_clock return bogus values. We make sure it does
+ * not appear to go backwards, and use jiffies to determine the maximum and
+ * minimum it could possibly have increased, and round down to the nearest
+ * jiffy when it falls outside this.
+ */
+static inline void niffy_diff(s64 *niff_diff, int jiff_diff)
+{
+	unsigned long min_diff, max_diff;
+
+	if (jiff_diff > 1)
+		min_diff = JIFFIES_TO_NS(jiff_diff - 1);
+	else
+		min_diff = 1;
+	/*  Round up to the nearest tick for maximum */
+	max_diff = JIFFIES_TO_NS(jiff_diff + 1);
+
+	if (unlikely(*niff_diff < min_diff || *niff_diff > max_diff))
+		*niff_diff = min_diff;
+}
+
+#ifdef CONFIG_SMP
+static inline int cpu_of(struct rq *rq)
+{
+	return rq->cpu;
+}
+
+/*
+ * Niffies are a globally increasing nanosecond counter. Whenever a runqueue
+ * clock is updated with the grq.lock held, it is an opportunity to update the
+ * niffies value. Any CPU can update it by adding how much its clock has
+ * increased since it last updated niffies, minus any added niffies by other
+ * CPUs.
+ */
+static inline void update_clocks(struct rq *rq)
+{
+	s64 ndiff;
+	long jdiff;
+
+	update_rq_clock(rq);
+	ndiff = rq->clock - rq->old_clock;
+	/* old_clock is only updated when we are updating niffies */
+	rq->old_clock = rq->clock;
+	ndiff -= grq.niffies - rq->last_niffy;
+	jdiff = jiffies - grq.last_jiffy;
+	niffy_diff(&ndiff, jdiff);
+	grq.last_jiffy += jdiff;
+	grq.niffies += ndiff;
+	rq->last_niffy = grq.niffies;
+}
+#else /* CONFIG_SMP */
+static inline int cpu_of(struct rq *rq)
+{
+	return 0;
+}
+
+static inline void update_clocks(struct rq *rq)
+{
+	s64 ndiff;
+	long jdiff;
+
+	update_rq_clock(rq);
+	ndiff = rq->clock - rq->old_clock;
+	rq->old_clock = rq->clock;
+	jdiff = jiffies - grq.last_jiffy;
+	niffy_diff(&ndiff, jdiff);
+	grq.last_jiffy += jdiff;
+	grq.niffies += ndiff;
+}
+#endif
+
+#include "stats.h"
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)	do { } while (0)
+#endif
+#ifndef finish_arch_switch
+# define finish_arch_switch(prev)	do { } while (0)
+#endif
+#ifndef finish_arch_post_lock_switch
+# define finish_arch_post_lock_switch()	do { } while (0)
+#endif
+
+/*
+ * All common locking functions performed on grq.lock. rq->clock is local to
+ * the CPU accessing it so it can be modified just with interrupts disabled
+ * when we're not updating niffies.
+ * Looking up task_rq must be done under grq.lock to be safe.
+ */
+static void update_rq_clock_task(struct rq *rq, s64 delta);
+
+static inline void update_rq_clock(struct rq *rq)
+{
+	s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
+
+	if (unlikely(delta < 0))
+		return;
+	rq->clock += delta;
+	update_rq_clock_task(rq, delta);
+}
+
+static inline bool task_running(struct task_struct *p)
+{
+	return p->on_cpu;
+}
+
+static inline void grq_lock(void)
+	__acquires(grq.lock)
+{
+	raw_spin_lock(&grq.lock);
+}
+
+static inline void grq_unlock(void)
+	__releases(grq.lock)
+{
+	raw_spin_unlock(&grq.lock);
+}
+
+static inline void grq_lock_irq(void)
+	__acquires(grq.lock)
+{
+	raw_spin_lock_irq(&grq.lock);
+}
+
+static inline void time_lock_grq(struct rq *rq)
+	__acquires(grq.lock)
+{
+	grq_lock();
+	update_clocks(rq);
+}
+
+static inline void grq_unlock_irq(void)
+	__releases(grq.lock)
+{
+	raw_spin_unlock_irq(&grq.lock);
+}
+
+static inline void grq_lock_irqsave(unsigned long *flags)
+	__acquires(grq.lock)
+{
+	raw_spin_lock_irqsave(&grq.lock, *flags);
+}
+
+static inline void grq_unlock_irqrestore(unsigned long *flags)
+	__releases(grq.lock)
+{
+	raw_spin_unlock_irqrestore(&grq.lock, *flags);
+}
+
+static inline struct rq
+*task_grq_lock(struct task_struct *p, unsigned long *flags)
+	__acquires(grq.lock)
+{
+	grq_lock_irqsave(flags);
+	return task_rq(p);
+}
+
+static inline struct rq
+*time_task_grq_lock(struct task_struct *p, unsigned long *flags)
+	__acquires(grq.lock)
+{
+	struct rq *rq = task_grq_lock(p, flags);
+	update_clocks(rq);
+	return rq;
+}
+
+static inline struct rq *task_grq_lock_irq(struct task_struct *p)
+	__acquires(grq.lock)
+{
+	grq_lock_irq();
+	return task_rq(p);
+}
+
+static inline void time_task_grq_lock_irq(struct task_struct *p)
+	__acquires(grq.lock)
+{
+	struct rq *rq = task_grq_lock_irq(p);
+	update_clocks(rq);
+}
+
+static inline void task_grq_unlock_irq(void)
+	__releases(grq.lock)
+{
+	grq_unlock_irq();
+}
+
+static inline void task_grq_unlock(unsigned long *flags)
+	__releases(grq.lock)
+{
+	grq_unlock_irqrestore(flags);
+}
+
+/**
+ * grunqueue_is_locked
+ *
+ * Returns true if the global runqueue is locked.
+ * This interface allows printk to be called with the runqueue lock
+ * held and know whether or not it is OK to wake up the klogd.
+ */
+bool grunqueue_is_locked(void)
+{
+	return raw_spin_is_locked(&grq.lock);
+}
+
+void grq_unlock_wait(void)
+	__releases(grq.lock)
+{
+	smp_mb(); /* spin-unlock-wait is not a full memory barrier */
+	raw_spin_unlock_wait(&grq.lock);
+}
+
+static inline void time_grq_lock(struct rq *rq, unsigned long *flags)
+	__acquires(grq.lock)
+{
+	local_irq_save(*flags);
+	time_lock_grq(rq);
+}
+
+static inline struct rq *__task_grq_lock(struct task_struct *p)
+	__acquires(grq.lock)
+{
+	grq_lock();
+	return task_rq(p);
+}
+
+static inline void __task_grq_unlock(void)
+	__releases(grq.lock)
+{
+	grq_unlock();
+}
+
+static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
+{
+}
+
+static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	/* this is a valid case when another task releases the spinlock */
+	grq.lock.owner = current;
+#endif
+	/*
+	 * If we are tracking spinlock dependencies then we have to
+	 * fix up the runqueue lock - which gets 'carried over' from
+	 * prev into current:
+	 */
+	spin_acquire(&grq.lock.dep_map, 0, 0, _THIS_IP_);
+
+	grq_unlock_irq();
+}
+
+static inline bool deadline_before(u64 deadline, u64 time)
+{
+	return (deadline < time);
+}
+
+static inline bool deadline_after(u64 deadline, u64 time)
+{
+	return (deadline > time);
+}
+
+/*
+ * A task that is queued but not running will be on the grq run list.
+ * A task that is not running or queued will not be on the grq run list.
+ * A task that is currently running will have ->on_cpu set but not on the
+ * grq run list.
+ */
+static inline bool task_queued(struct task_struct *p)
+{
+	return (!list_empty(&p->run_list));
+}
+
+/*
+ * Removing from the global runqueue. Enter with grq locked.
+ */
+static void dequeue_task(struct task_struct *p)
+{
+	list_del_init(&p->run_list);
+	if (list_empty(grq.queue + p->prio))
+		__clear_bit(p->prio, grq.prio_bitmap);
+	sched_info_dequeued(task_rq(p), p);
+}
+
+/*
+ * To determine if it's safe for a task of SCHED_IDLEPRIO to actually run as
+ * an idle task, we ensure none of the following conditions are met.
+ */
+static bool idleprio_suitable(struct task_struct *p)
+{
+	return (!freezing(p) && !signal_pending(p) &&
+		!(task_contributes_to_load(p)) && !(p->flags & (PF_EXITING)));
+}
+
+/*
+ * To determine if a task of SCHED_ISO can run in pseudo-realtime, we check
+ * that the iso_refractory flag is not set.
+ */
+static bool isoprio_suitable(void)
+{
+	return !grq.iso_refractory;
+}
+
+/*
+ * Adding to the global runqueue. Enter with grq locked.
+ */
+static void enqueue_task(struct task_struct *p, struct rq *rq)
+{
+	if (!rt_task(p)) {
+		/* Check it hasn't gotten rt from PI */
+		if ((idleprio_task(p) && idleprio_suitable(p)) ||
+		   (iso_task(p) && isoprio_suitable()))
+			p->prio = p->normal_prio;
+		else
+			p->prio = NORMAL_PRIO;
+	}
+	__set_bit(p->prio, grq.prio_bitmap);
+	list_add_tail(&p->run_list, grq.queue + p->prio);
+	sched_info_queued(rq, p);
+}
+
+static inline void requeue_task(struct task_struct *p)
+{
+	sched_info_queued(task_rq(p), p);
+}
+
+/*
+ * Returns the relative length of deadline all compared to the shortest
+ * deadline which is that of nice -20.
+ */
+static inline int task_prio_ratio(struct task_struct *p)
+{
+	return prio_ratios[TASK_USER_PRIO(p)];
+}
+
+/*
+ * task_timeslice - all tasks of all priorities get the exact same timeslice
+ * length. CPU distribution is handled by giving different deadlines to
+ * tasks of different priorities. Use 128 as the base value for fast shifts.
+ */
+static inline int task_timeslice(struct task_struct *p)
+{
+	return (rr_interval * task_prio_ratio(p) / 128);
+}
+
+static void resched_task(struct task_struct *p);
+
+static inline void resched_curr(struct rq *rq)
+{
+	resched_task(rq->curr);
+}
+
+/*
+ * qnr is the "queued but not running" count which is the total number of
+ * tasks on the global runqueue list waiting for cpu time but not actually
+ * currently running on a cpu.
+ */
+static inline void inc_qnr(void)
+{
+	grq.qnr++;
+}
+
+static inline void dec_qnr(void)
+{
+	grq.qnr--;
+}
+
+static inline int queued_notrunning(void)
+{
+	return grq.qnr;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * The cpu_idle_map stores a bitmap of all the CPUs currently idle to
+ * allow easy lookup of whether any suitable idle CPUs are available.
+ * It's cheaper to maintain a binary yes/no if there are any idle CPUs on the
+ * idle_cpus variable than to do a full bitmask check when we are busy.
+ */
+static inline void set_cpuidle_map(int cpu)
+{
+	if (likely(cpu_online(cpu))) {
+		cpumask_set_cpu(cpu, &grq.cpu_idle_map);
+		grq.idle_cpus = true;
+	}
+}
+
+static inline void clear_cpuidle_map(int cpu)
+{
+	cpumask_clear_cpu(cpu, &grq.cpu_idle_map);
+	if (cpumask_empty(&grq.cpu_idle_map))
+		grq.idle_cpus = false;
+}
+
+static bool suitable_idle_cpus(struct task_struct *p)
+{
+	if (!grq.idle_cpus)
+		return false;
+	return (cpumask_intersects(&p->cpus_allowed, &grq.cpu_idle_map));
+}
+
+#define CPUIDLE_DIFF_THREAD	(1)
+#define CPUIDLE_DIFF_CORE	(2)
+#define CPUIDLE_CACHE_BUSY	(4)
+#define CPUIDLE_DIFF_CPU	(8)
+#define CPUIDLE_THREAD_BUSY	(16)
+#define CPUIDLE_THROTTLED	(32)
+#define CPUIDLE_DIFF_NODE	(64)
+
+static inline bool scaling_rq(struct rq *rq);
+
+/*
+ * The best idle CPU is chosen according to the CPUIDLE ranking above where the
+ * lowest value would give the most suitable CPU to schedule p onto next. The
+ * order works out to be the following:
+ *
+ * Same core, idle or busy cache, idle or busy threads
+ * Other core, same cache, idle or busy cache, idle threads.
+ * Same node, other CPU, idle cache, idle threads.
+ * Same node, other CPU, busy cache, idle threads.
+ * Other core, same cache, busy threads.
+ * Same node, other CPU, busy threads.
+ * Other node, other CPU, idle cache, idle threads.
+ * Other node, other CPU, busy cache, idle threads.
+ * Other node, other CPU, busy threads.
+ */
+static int best_mask_cpu(int best_cpu, struct rq *rq, cpumask_t *tmpmask)
+{
+	int best_ranking = CPUIDLE_DIFF_NODE | CPUIDLE_THROTTLED |
+		CPUIDLE_THREAD_BUSY | CPUIDLE_DIFF_CPU | CPUIDLE_CACHE_BUSY |
+		CPUIDLE_DIFF_CORE | CPUIDLE_DIFF_THREAD;
+	int cpu_tmp;
+
+	if (cpumask_test_cpu(best_cpu, tmpmask))
+		goto out;
+
+	for_each_cpu(cpu_tmp, tmpmask) {
+		int ranking, locality;
+		struct rq *tmp_rq;
+
+		ranking = 0;
+		tmp_rq = cpu_rq(cpu_tmp);
+
+		locality = rq->cpu_locality[cpu_tmp];
+#ifdef CONFIG_NUMA
+		if (locality > 3)
+			ranking |= CPUIDLE_DIFF_NODE;
+		else
+#endif
+		if (locality > 2)
+			ranking |= CPUIDLE_DIFF_CPU;
+#ifdef CONFIG_SCHED_MC
+		else if (locality == 2)
+			ranking |= CPUIDLE_DIFF_CORE;
+		if (!(tmp_rq->cache_idle(cpu_tmp)))
+			ranking |= CPUIDLE_CACHE_BUSY;
+#endif
+#ifdef CONFIG_SCHED_SMT
+		if (locality == 1)
+			ranking |= CPUIDLE_DIFF_THREAD;
+		if (!(tmp_rq->siblings_idle(cpu_tmp)))
+			ranking |= CPUIDLE_THREAD_BUSY;
+#endif
+		if (scaling_rq(tmp_rq))
+			ranking |= CPUIDLE_THROTTLED;
+
+		if (ranking < best_ranking) {
+			best_cpu = cpu_tmp;
+			best_ranking = ranking;
+		}
+	}
+out:
+	return best_cpu;
+}
+
+static void resched_best_mask(int best_cpu, struct rq *rq, cpumask_t *tmpmask)
+{
+	best_cpu = best_mask_cpu(best_cpu, rq, tmpmask);
+	resched_curr(cpu_rq(best_cpu));
+}
+
+bool cpus_share_cache(int this_cpu, int that_cpu)
+{
+	struct rq *this_rq = cpu_rq(this_cpu);
+
+	return (this_rq->cpu_locality[that_cpu] < 3);
+}
+
+#ifdef CONFIG_SCHED_SMT
+#ifdef CONFIG_SMT_NICE
+static const cpumask_t *thread_cpumask(int cpu);
+
+/* Find the best real time priority running on any SMT siblings of cpu and if
+ * none are running, the static priority of the best deadline task running.
+ * The lookups to the other runqueues is done lockless as the occasional wrong
+ * value would be harmless. */
+static int best_smt_bias(int cpu)
+{
+	int other_cpu, best_bias = 0;
+
+	for_each_cpu(other_cpu, thread_cpumask(cpu)) {
+		struct rq *rq;
+
+		if (other_cpu == cpu)
+			continue;
+		rq = cpu_rq(other_cpu);
+		if (rq_idle(rq))
+			continue;
+		if (!rq->online)
+			continue;
+		if (!rq->rq_mm)
+			continue;
+		if (likely(rq->rq_smt_bias > best_bias))
+			best_bias = rq->rq_smt_bias;
+	}
+	return best_bias;
+}
+
+static int task_prio_bias(struct task_struct *p)
+{
+	if (rt_task(p))
+		return 1 << 30;
+	else if (task_running_iso(p))
+		return 1 << 29;
+	else if (task_running_idle(p))
+		return 0;
+	return MAX_PRIO - p->static_prio;
+}
+
+/* We've already decided p can run on CPU, now test if it shouldn't for SMT
+ * nice reasons. */
+static bool smt_should_schedule(struct task_struct *p, int cpu)
+{
+	int best_bias, task_bias;
+
+	/* Kernel threads always run */
+	if (unlikely(!p->mm))
+		return true;
+	if (rt_task(p))
+		return true;
+	if (!idleprio_suitable(p))
+		return true;
+	best_bias = best_smt_bias(cpu);
+	/* The smt siblings are all idle or running IDLEPRIO */
+	if (best_bias < 1)
+		return true;
+	task_bias = task_prio_bias(p);
+	if (task_bias < 1)
+		return false;
+	if (task_bias >= best_bias)
+		return true;
+	/* Dither 25% cpu of normal tasks regardless of nice difference */
+	if (best_bias % 4 == 1)
+		return true;
+	/* Sorry, you lose */
+	return false;
+}
+#endif
+#endif
+
+static bool resched_best_idle(struct task_struct *p)
+{
+	cpumask_t tmpmask;
+	int best_cpu;
+
+	cpumask_and(&tmpmask, &p->cpus_allowed, &grq.cpu_idle_map);
+	best_cpu = best_mask_cpu(task_cpu(p), task_rq(p), &tmpmask);
+#ifdef CONFIG_SMT_NICE
+	if (!smt_should_schedule(p, best_cpu))
+		return false;
+#endif
+	resched_curr(cpu_rq(best_cpu));
+	return true;
+}
+
+static inline void resched_suitable_idle(struct task_struct *p)
+{
+	if (suitable_idle_cpus(p))
+		resched_best_idle(p);
+}
+/*
+ * Flags to tell us whether this CPU is running a CPU frequency governor that
+ * has slowed its speed or not. No locking required as the very rare wrongly
+ * read value would be harmless.
+ */
+void cpu_scaling(int cpu)
+{
+	cpu_rq(cpu)->scaling = true;
+}
+
+void cpu_nonscaling(int cpu)
+{
+	cpu_rq(cpu)->scaling = false;
+}
+
+static inline bool scaling_rq(struct rq *rq)
+{
+	return rq->scaling;
+}
+
+static inline int locality_diff(int cpu, struct rq *rq)
+{
+	return rq->cpu_locality[cpu];
+}
+#else /* CONFIG_SMP */
+static inline void set_cpuidle_map(int cpu)
+{
+}
+
+static inline void clear_cpuidle_map(int cpu)
+{
+}
+
+static inline bool suitable_idle_cpus(struct task_struct *p)
+{
+	return uprq->curr == uprq->idle;
+}
+
+static inline void resched_suitable_idle(struct task_struct *p)
+{
+}
+
+void cpu_scaling(int __unused)
+{
+}
+
+void cpu_nonscaling(int __unused)
+{
+}
+
+/*
+ * Although CPUs can scale in UP, there is nowhere else for tasks to go so this
+ * always returns 0.
+ */
+static inline bool scaling_rq(struct rq *rq)
+{
+	return false;
+}
+
+static inline int locality_diff(int cpu, struct rq *rq)
+{
+	return 0;
+}
+#endif /* CONFIG_SMP */
+EXPORT_SYMBOL_GPL(cpu_scaling);
+EXPORT_SYMBOL_GPL(cpu_nonscaling);
+
+static inline int normal_prio(struct task_struct *p)
+{
+	if (has_rt_policy(p))
+		return MAX_RT_PRIO - 1 - p->rt_priority;
+	if (idleprio_task(p))
+		return IDLE_PRIO;
+	if (iso_task(p))
+		return ISO_PRIO;
+	return NORMAL_PRIO;
+}
+
+/*
+ * Calculate the current priority, i.e. the priority
+ * taken into account by the scheduler. This value might
+ * be boosted by RT tasks as it will be RT if the task got
+ * RT-boosted. If not then it returns p->normal_prio.
+ */
+static int effective_prio(struct task_struct *p)
+{
+	p->normal_prio = normal_prio(p);
+	/*
+	 * If we are RT tasks or we were boosted to RT priority,
+	 * keep the priority unchanged. Otherwise, update priority
+	 * to the normal priority:
+	 */
+	if (!rt_prio(p->prio))
+		return p->normal_prio;
+	return p->prio;
+}
+
+/*
+ * activate_task - move a task to the runqueue. Enter with grq locked.
+ */
+static void activate_task(struct task_struct *p, struct rq *rq)
+{
+	update_clocks(rq);
+
+	/*
+	 * Sleep time is in units of nanosecs, so shift by 20 to get a
+	 * milliseconds-range estimation of the amount of time that the task
+	 * spent sleeping:
+	 */
+	if (unlikely(prof_on == SLEEP_PROFILING)) {
+		if (p->state == TASK_UNINTERRUPTIBLE)
+			profile_hits(SLEEP_PROFILING, (void *)get_wchan(p),
+				     (rq->clock_task - p->last_ran) >> 20);
+	}
+
+	p->prio = effective_prio(p);
+	if (task_contributes_to_load(p))
+		grq.nr_uninterruptible--;
+	enqueue_task(p, rq);
+	rq->soft_affined++;
+	p->on_rq = 1;
+	grq.nr_running++;
+	inc_qnr();
+}
+
+static inline void clear_sticky(struct task_struct *p);
+
+/*
+ * deactivate_task - If it's running, it's not on the grq and we can just
+ * decrement the nr_running. Enter with grq locked.
+ */
+static inline void deactivate_task(struct task_struct *p, struct rq *rq)
+{
+	if (task_contributes_to_load(p))
+		grq.nr_uninterruptible++;
+	rq->soft_affined--;
+	p->on_rq = 0;
+	grq.nr_running--;
+	clear_sticky(p);
+}
+
+#ifdef CONFIG_SMP
+void set_task_cpu(struct task_struct *p, unsigned int cpu)
+{
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * The caller should hold grq lock.
+	 */
+	WARN_ON_ONCE(debug_locks && !lockdep_is_held(&grq.lock));
+#endif
+	if (task_cpu(p) == cpu)
+		return;
+	trace_sched_migrate_task(p, cpu);
+	perf_event_task_migrate(p);
+
+	/*
+	 * After ->cpu is set up to a new value, task_grq_lock(p, ...) can be
+	 * successfully executed on another CPU. We must ensure that updates of
+	 * per-task data have been completed by this moment.
+	 */
+	smp_wmb();
+	if (p->on_rq) {
+		task_rq(p)->soft_affined--;
+		cpu_rq(cpu)->soft_affined++;
+	}
+	task_thread_info(p)->cpu = cpu;
+}
+
+static inline void clear_sticky(struct task_struct *p)
+{
+	p->sticky = false;
+}
+
+static inline bool task_sticky(struct task_struct *p)
+{
+	return p->sticky;
+}
+
+/* Reschedule the best idle CPU that is not this one. */
+static void
+resched_closest_idle(struct rq *rq, int cpu, struct task_struct *p)
+{
+	cpumask_t tmpmask;
+
+	cpumask_and(&tmpmask, &p->cpus_allowed, &grq.cpu_idle_map);
+	cpumask_clear_cpu(cpu, &tmpmask);
+	if (cpumask_empty(&tmpmask))
+		return;
+	resched_best_mask(cpu, rq, &tmpmask);
+}
+
+/*
+ * We set the sticky flag on a task that is descheduled involuntarily meaning
+ * it is awaiting further CPU time. If the last sticky task is still sticky
+ * but unlucky enough to not be the next task scheduled, we unstick it and try
+ * to find it an idle CPU. Realtime tasks do not stick to minimise their
+ * latency at all times.
+ */
+static inline void
+swap_sticky(struct rq *rq, int cpu, struct task_struct *p)
+{
+	if (rq->sticky_task) {
+		if (rq->sticky_task == p) {
+			p->sticky = true;
+			return;
+		}
+		if (task_sticky(rq->sticky_task)) {
+			clear_sticky(rq->sticky_task);
+			resched_closest_idle(rq, cpu, rq->sticky_task);
+		}
+	}
+	if (!rt_task(p)) {
+		p->sticky = true;
+		rq->sticky_task = p;
+	} else {
+		resched_closest_idle(rq, cpu, p);
+		rq->sticky_task = NULL;
+	}
+}
+
+static inline void unstick_task(struct rq *rq, struct task_struct *p)
+{
+	rq->sticky_task = NULL;
+	clear_sticky(p);
+}
+#else
+static inline void clear_sticky(struct task_struct *p)
+{
+}
+
+static inline bool task_sticky(struct task_struct *p)
+{
+	return false;
+}
+
+static inline void
+swap_sticky(struct rq *rq, int cpu, struct task_struct *p)
+{
+}
+
+static inline void unstick_task(struct rq *rq, struct task_struct *p)
+{
+}
+#endif
+
+/*
+ * Move a task off the global queue and take it to a cpu for it will
+ * become the running task.
+ */
+static inline void take_task(int cpu, struct task_struct *p)
+{
+	set_task_cpu(p, cpu);
+	dequeue_task(p);
+	clear_sticky(p);
+	dec_qnr();
+}
+
+/*
+ * Returns a descheduling task to the grq runqueue unless it is being
+ * deactivated.
+ */
+static inline void return_task(struct task_struct *p, struct rq *rq, bool deactivate)
+{
+	if (deactivate)
+		deactivate_task(p, rq);
+	else {
+		inc_qnr();
+		enqueue_task(p, rq);
+	}
+}
+
+/* Enter with grq lock held. We know p is on the local cpu */
+static inline void __set_tsk_resched(struct task_struct *p)
+{
+	set_tsk_need_resched(p);
+	set_preempt_need_resched();
+}
+
+/*
+ * resched_task - mark a task 'to be rescheduled now'.
+ *
+ * On UP this means the setting of the need_resched flag, on SMP it
+ * might also involve a cross-CPU call to trigger the scheduler on
+ * the target CPU.
+ */
+void resched_task(struct task_struct *p)
+{
+	int cpu;
+
+	lockdep_assert_held(&grq.lock);
+
+	if (test_tsk_need_resched(p))
+		return;
+
+	set_tsk_need_resched(p);
+
+	cpu = task_cpu(p);
+	if (cpu == smp_processor_id()) {
+		set_preempt_need_resched();
+		return;
+	}
+
+	smp_send_reschedule(cpu);
+}
+
+/**
+ * task_curr - is this task currently executing on a CPU?
+ * @p: the task in question.
+ *
+ * Return: 1 if the task is currently executing. 0 otherwise.
+ */
+inline int task_curr(const struct task_struct *p)
+{
+	return cpu_curr(task_cpu(p)) == p;
+}
+
+#ifdef CONFIG_SMP
+struct migration_req {
+	struct task_struct *task;
+	int dest_cpu;
+};
+
+/*
+ * wait_task_inactive - wait for a thread to unschedule.
+ *
+ * If @match_state is nonzero, it's the @p->state value just checked and
+ * not expected to change.  If it changes, i.e. @p might have woken up,
+ * then return zero.  When we succeed in waiting for @p to be off its CPU,
+ * we return a positive number (its total switch count).  If a second call
+ * a short while later returns the same number, the caller can be sure that
+ * @p has remained unscheduled the whole time.
+ *
+ * The caller must ensure that the task *will* unschedule sometime soon,
+ * else this function might spin for a *long* time. This function can't
+ * be called with interrupts off, or it may introduce deadlock with
+ * smp_call_function() if an IPI is sent by the same process we are
+ * waiting to become inactive.
+ */
+unsigned long wait_task_inactive(struct task_struct *p, long match_state)
+{
+	unsigned long flags;
+	bool running, on_rq;
+	unsigned long ncsw;
+	struct rq *rq;
+
+	for (;;) {
+		rq = task_rq(p);
+
+		/*
+		 * If the task is actively running on another CPU
+		 * still, just relax and busy-wait without holding
+		 * any locks.
+		 *
+		 * NOTE! Since we don't hold any locks, it's not
+		 * even sure that "rq" stays as the right runqueue!
+		 * But we don't care, since this will return false
+		 * if the runqueue has changed and p is actually now
+		 * running somewhere else!
+		 */
+		while (task_running(p) && p == rq->curr) {
+			if (match_state && unlikely(p->state != match_state))
+				return 0;
+			cpu_relax();
+		}
+
+		/*
+		 * Ok, time to look more closely! We need the grq
+		 * lock now, to be *sure*. If we're wrong, we'll
+		 * just go back and repeat.
+		 */
+		rq = task_grq_lock(p, &flags);
+		trace_sched_wait_task(p);
+		running = task_running(p);
+		on_rq = p->on_rq;
+		ncsw = 0;
+		if (!match_state || p->state == match_state)
+			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+		task_grq_unlock(&flags);
+
+		/*
+		 * If it changed from the expected state, bail out now.
+		 */
+		if (unlikely(!ncsw))
+			break;
+
+		/*
+		 * Was it really running after all now that we
+		 * checked with the proper locks actually held?
+		 *
+		 * Oops. Go back and try again..
+		 */
+		if (unlikely(running)) {
+			cpu_relax();
+			continue;
+		}
+
+		/*
+		 * It's not enough that it's not actively running,
+		 * it must be off the runqueue _entirely_, and not
+		 * preempted!
+		 *
+		 * So if it was still runnable (but just not actively
+		 * running right now), it's preempted, and we should
+		 * yield - it could be a while.
+		 */
+		if (unlikely(on_rq)) {
+			ktime_t to = ktime_set(0, NSEC_PER_SEC / HZ);
+
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			schedule_hrtimeout(&to, HRTIMER_MODE_REL);
+			continue;
+		}
+
+		/*
+		 * Ahh, all good. It wasn't running, and it wasn't
+		 * runnable, which means that it will never become
+		 * running in the future either. We're all done!
+		 */
+		break;
+	}
+
+	return ncsw;
+}
+
+/***
+ * kick_process - kick a running thread to enter/exit the kernel
+ * @p: the to-be-kicked thread
+ *
+ * Cause a process which is running on another CPU to enter
+ * kernel-mode, without any delay. (to get signals handled.)
+ *
+ * NOTE: this function doesn't have to take the runqueue lock,
+ * because all it wants to ensure is that the remote task enters
+ * the kernel. If the IPI races and the task has been migrated
+ * to another CPU then no harm is done and the purpose has been
+ * achieved as well.
+ */
+void kick_process(struct task_struct *p)
+{
+	int cpu;
+
+	preempt_disable();
+	cpu = task_cpu(p);
+	if ((cpu != smp_processor_id()) && task_curr(p))
+		smp_send_reschedule(cpu);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(kick_process);
+#endif
+
+/*
+ * RT tasks preempt purely on priority. SCHED_NORMAL tasks preempt on the
+ * basis of earlier deadlines. SCHED_IDLEPRIO don't preempt anything else or
+ * between themselves, they cooperatively multitask. An idle rq scores as
+ * prio PRIO_LIMIT so it is always preempted.
+ */
+static inline bool
+can_preempt(struct task_struct *p, int prio, u64 deadline)
+{
+	/* Better static priority RT task or better policy preemption */
+	if (p->prio < prio)
+		return true;
+	if (p->prio > prio)
+		return false;
+	/* SCHED_NORMAL, BATCH and ISO will preempt based on deadline */
+	if (!deadline_before(p->deadline, deadline))
+		return false;
+	return true;
+}
+
+#ifdef CONFIG_SMP
+#define cpu_online_map		(*(cpumask_t *)cpu_online_mask)
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Check to see if there is a task that is affined only to offline CPUs but
+ * still wants runtime. This happens to kernel threads during suspend/halt and
+ * disabling of CPUs.
+ */
+static inline bool online_cpus(struct task_struct *p)
+{
+	return (likely(cpumask_intersects(&cpu_online_map, &p->cpus_allowed)));
+}
+#else /* CONFIG_HOTPLUG_CPU */
+/* All available CPUs are always online without hotplug. */
+static inline bool online_cpus(struct task_struct *p)
+{
+	return true;
+}
+#endif
+
+/*
+ * Check to see if p can run on cpu, and if not, whether there are any online
+ * CPUs it can run on instead.
+ */
+static inline bool needs_other_cpu(struct task_struct *p, int cpu)
+{
+	if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed)))
+		return true;
+	return false;
+}
+
+/*
+ * When all else is equal, still prefer this_rq.
+ */
+static void try_preempt(struct task_struct *p, struct rq *this_rq)
+{
+	struct rq *highest_prio_rq = NULL;
+	int cpu, highest_prio;
+	u64 latest_deadline;
+	cpumask_t tmp;
+
+	/*
+	 * We clear the sticky flag here because for a task to have called
+	 * try_preempt with the sticky flag enabled means some complicated
+	 * re-scheduling has occurred and we should ignore the sticky flag.
+	 */
+	clear_sticky(p);
+
+	if (suitable_idle_cpus(p) && resched_best_idle(p))
+		return;
+
+	/* IDLEPRIO tasks never preempt anything but idle */
+	if (p->policy == SCHED_IDLEPRIO)
+		return;
+
+	if (likely(online_cpus(p)))
+		cpumask_and(&tmp, &cpu_online_map, &p->cpus_allowed);
+	else
+		return;
+
+	highest_prio = latest_deadline = 0;
+
+	for_each_cpu(cpu, &tmp) {
+		struct rq *rq;
+		int rq_prio;
+
+		rq = cpu_rq(cpu);
+		rq_prio = rq->rq_prio;
+		if (rq_prio < highest_prio)
+			continue;
+
+		if (rq_prio > highest_prio ||
+		    deadline_after(rq->rq_deadline, latest_deadline)) {
+			latest_deadline = rq->rq_deadline;
+			highest_prio = rq_prio;
+			highest_prio_rq = rq;
+		}
+	}
+
+	if (likely(highest_prio_rq)) {
+#ifdef CONFIG_SMT_NICE
+		cpu = cpu_of(highest_prio_rq);
+		if (!smt_should_schedule(p, cpu))
+			return;
+#endif
+		if (can_preempt(p, highest_prio, highest_prio_rq->rq_deadline))
+			resched_curr(highest_prio_rq);
+	}
+}
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  const struct cpumask *new_mask, bool check);
+#else /* CONFIG_SMP */
+static inline bool needs_other_cpu(struct task_struct *p, int cpu)
+{
+	return false;
+}
+
+static void try_preempt(struct task_struct *p, struct rq *this_rq)
+{
+	if (p->policy == SCHED_IDLEPRIO)
+		return;
+	if (can_preempt(p, uprq->rq_prio, uprq->rq_deadline))
+		resched_curr(uprq);
+}
+
+static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+					 const struct cpumask *new_mask, bool check)
+{
+	return set_cpus_allowed_ptr(p, new_mask);
+}
+#endif /* CONFIG_SMP */
+
+static void
+ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
+{
+#ifdef CONFIG_SCHEDSTATS
+	struct rq *rq = this_rq();
+
+#ifdef CONFIG_SMP
+	int this_cpu = smp_processor_id();
+
+	if (cpu == this_cpu)
+		schedstat_inc(rq, ttwu_local);
+	else {
+		struct sched_domain *sd;
+
+		rcu_read_lock();
+		for_each_domain(this_cpu, sd) {
+			if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
+				schedstat_inc(sd, ttwu_wake_remote);
+				break;
+			}
+		}
+		rcu_read_unlock();
+	}
+
+#endif /* CONFIG_SMP */
+
+	schedstat_inc(rq, ttwu_count);
+#endif /* CONFIG_SCHEDSTATS */
+}
+
+void wake_up_if_idle(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	rcu_read_lock();
+
+	if (!is_idle_task(rcu_dereference(rq->curr)))
+		goto out;
+
+	grq_lock_irqsave(&flags);
+	if (likely(is_idle_task(rq->curr)))
+		smp_send_reschedule(cpu);
+	/* Else cpu is not in idle, do nothing here */
+	grq_unlock_irqrestore(&flags);
+
+out:
+	rcu_read_unlock();
+}
+
+#ifdef CONFIG_SMP
+void scheduler_ipi(void)
+{
+	/*
+	 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
+	 * TIF_NEED_RESCHED remotely (for the first time) will also send
+	 * this IPI.
+	 */
+	preempt_fold_need_resched();
+}
+#endif
+
+static inline void ttwu_activate(struct task_struct *p, struct rq *rq,
+				 bool is_sync)
+{
+	activate_task(p, rq);
+
+	/*
+	 * Sync wakeups (i.e. those types of wakeups where the waker
+	 * has indicated that it will leave the CPU in short order)
+	 * don't trigger a preemption if there are no idle cpus,
+	 * instead waiting for current to deschedule.
+	 */
+	if (!is_sync || suitable_idle_cpus(p))
+		try_preempt(p, rq);
+}
+
+static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
+					bool success)
+{
+	trace_sched_wakeup(p);
+	p->state = TASK_RUNNING;
+
+	/*
+	 * if a worker is waking up, notify workqueue. Note that on BFS, we
+	 * don't really know what cpu it will be, so we fake it for
+	 * wq_worker_waking_up :/
+	 */
+	if ((p->flags & PF_WQ_WORKER) && success)
+		wq_worker_waking_up(p, cpu_of(rq));
+}
+
+/*
+ * wake flags
+ */
+#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 */
+
+/***
+ * try_to_wake_up - wake up a thread
+ * @p: the thread to be awakened
+ * @state: the mask of task states that can be woken
+ * @wake_flags: wake modifier flags (WF_*)
+ *
+ * Put it on the run-queue if it's not already there. The "current"
+ * thread is always on the run-queue (except when the actual
+ * re-schedule is in progress), and as such you're allowed to do
+ * the simpler "current->state = TASK_RUNNING" to mark yourself
+ * runnable without the overhead of this.
+ *
+ * Return: %true if @p was woken up, %false if it was already running.
+ * or @state didn't match @p's state.
+ */
+static bool try_to_wake_up(struct task_struct *p, unsigned int state,
+			  int wake_flags)
+{
+	bool success = false;
+	unsigned long flags;
+	struct rq *rq;
+	int cpu;
+
+	get_cpu();
+
+	/*
+	 * If we are going to wake up a thread waiting for CONDITION we
+	 * need to ensure that CONDITION=1 done by the caller can not be
+	 * reordered with p->state check below. This pairs with mb() in
+	 * set_current_state() the waiting thread does.
+	 */
+	smp_mb__before_spinlock();
+
+	/*
+	 * No need to do time_lock_grq as we only need to update the rq clock
+	 * if we activate the task
+	 */
+	rq = task_grq_lock(p, &flags);
+	cpu = task_cpu(p);
+
+	/* state is a volatile long, どうして、分からない */
+	if (!((unsigned int)p->state & state))
+		goto out_unlock;
+
+	trace_sched_waking(p);
+
+	if (task_queued(p) || task_running(p))
+		goto out_running;
+
+	ttwu_activate(p, rq, wake_flags & WF_SYNC);
+	success = true;
+
+out_running:
+	ttwu_post_activation(p, rq, success);
+out_unlock:
+	task_grq_unlock(&flags);
+
+	ttwu_stat(p, cpu, wake_flags);
+
+	put_cpu();
+
+	return success;
+}
+
+/**
+ * try_to_wake_up_local - try to wake up a local task with grq 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 grq is locked and, @p is not the current task.
+ * grq stays locked over invocation.
+ */
+static void try_to_wake_up_local(struct task_struct *p)
+{
+	struct rq *rq = task_rq(p);
+	bool success = false;
+
+	lockdep_assert_held(&grq.lock);
+
+	if (!(p->state & TASK_NORMAL))
+		return;
+
+	trace_sched_waking(p);
+
+	if (!task_queued(p)) {
+		if (likely(!task_running(p))) {
+			schedstat_inc(rq, ttwu_count);
+			schedstat_inc(rq, ttwu_local);
+		}
+		ttwu_activate(p, rq, false);
+		ttwu_stat(p, smp_processor_id(), 0);
+		success = true;
+	}
+	ttwu_post_activation(p, rq, success);
+}
+
+/**
+ * wake_up_process - Wake up a specific process
+ * @p: The process to be woken up.
+ *
+ * Attempt to wake up the nominated process and move it to the set of runnable
+ * processes.
+ *
+ * Return: 1 if the process was woken up, 0 if it was already running.
+ *
+ * It may be assumed that this function implies a write memory barrier before
+ * changing the task state if and only if any tasks are woken up.
+ */
+int wake_up_process(struct task_struct *p)
+{
+	return try_to_wake_up(p, TASK_NORMAL, 0);
+}
+EXPORT_SYMBOL(wake_up_process);
+
+int wake_up_state(struct task_struct *p, unsigned int state)
+{
+	return try_to_wake_up(p, state, 0);
+}
+
+static void time_slice_expired(struct task_struct *p);
+
+/*
+ * Perform scheduler related setup for a newly forked process p.
+ * p is forked by current.
+ */
+int sched_fork(unsigned long __maybe_unused clone_flags, struct task_struct *p)
+{
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+	INIT_HLIST_HEAD(&p->preempt_notifiers);
+#endif
+	/*
+	 * The process state is set to the same value of the process executing
+	 * do_fork() code. That is running. This guarantees that nobody will
+	 * actually run it, and a signal or other external event cannot wake
+	 * it up and insert it on the runqueue either.
+	 */
+
+	/* Should be reset in fork.c but done here for ease of bfs patching */
+	p->on_rq =
+	p->utime =
+	p->stime =
+	p->utimescaled =
+	p->stimescaled =
+	p->sched_time =
+	p->stime_pc =
+	p->utime_pc = 0;
+
+	/*
+	 * Revert to default priority/policy on fork if requested.
+	 */
+	if (unlikely(p->sched_reset_on_fork)) {
+		if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
+			p->policy = SCHED_NORMAL;
+			p->normal_prio = normal_prio(p);
+		}
+
+		if (PRIO_TO_NICE(p->static_prio) < 0) {
+			p->static_prio = NICE_TO_PRIO(0);
+			p->normal_prio = p->static_prio;
+		}
+
+		/*
+		 * We don't need the reset flag anymore after the fork. It has
+		 * fulfilled its duty:
+		 */
+		p->sched_reset_on_fork = 0;
+	}
+
+	INIT_LIST_HEAD(&p->run_list);
+#ifdef CONFIG_SCHED_INFO
+	if (unlikely(sched_info_on()))
+		memset(&p->sched_info, 0, sizeof(p->sched_info));
+#endif
+	p->on_cpu = false;
+	clear_sticky(p);
+	init_task_preempt_count(p);
+	return 0;
+}
+
+/*
+ * wake_up_new_task - wake up a newly created task for the first time.
+ *
+ * This function will do some initial scheduler statistics housekeeping
+ * that must be done for every newly created context, then puts the task
+ * on the runqueue and wakes it.
+ */
+void wake_up_new_task(struct task_struct *p)
+{
+	struct task_struct *parent;
+	unsigned long flags;
+	struct rq *rq;
+
+	parent = p->parent;
+	rq = task_grq_lock(p, &flags);
+
+	/*
+	 * Reinit new task deadline as its creator deadline could have changed
+	 * since call to dup_task_struct().
+	 */
+	p->deadline = rq->rq_deadline;
+
+	/*
+	 * If the task is a new process, current and parent are the same. If
+	 * the task is a new thread in the thread group, it will have much more
+	 * in common with current than with the parent.
+	 */
+	set_task_cpu(p, task_cpu(rq->curr));
+
+	/*
+	 * Make sure we do not leak PI boosting priority to the child.
+	 */
+	p->prio = rq->curr->normal_prio;
+
+	activate_task(p, rq);
+	trace_sched_wakeup_new(p);
+	if (unlikely(p->policy == SCHED_FIFO))
+		goto after_ts_init;
+
+	/*
+	 * Share the timeslice between parent and child, thus the
+	 * total amount of pending timeslices in the system doesn't change,
+	 * resulting in more scheduling fairness. If it's negative, it won't
+	 * matter since that's the same as being 0. current's time_slice is
+	 * actually in rq_time_slice when it's running, as is its last_ran
+	 * value. rq->rq_deadline is only modified within schedule() so it
+	 * is always equal to current->deadline.
+	 */
+	p->last_ran = rq->rq_last_ran;
+	if (likely(rq->rq_time_slice >= RESCHED_US * 2)) {
+		rq->rq_time_slice /= 2;
+		p->time_slice = rq->rq_time_slice;
+after_ts_init:
+		if (rq->curr == parent && !suitable_idle_cpus(p)) {
+			/*
+			 * The VM isn't cloned, so we're in a good position to
+			 * do child-runs-first in anticipation of an exec. This
+			 * usually avoids a lot of COW overhead.
+			 */
+			__set_tsk_resched(parent);
+		} else
+			try_preempt(p, rq);
+	} else {
+		if (rq->curr == parent) {
+			/*
+			* Forking task has run out of timeslice. Reschedule it and
+			* start its child with a new time slice and deadline. The
+			* child will end up running first because its deadline will
+			* be slightly earlier.
+			*/
+			rq->rq_time_slice = 0;
+			__set_tsk_resched(parent);
+		}
+		time_slice_expired(p);
+	}
+	task_grq_unlock(&flags);
+}
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+static struct static_key preempt_notifier_key = STATIC_KEY_INIT_FALSE;
+
+void preempt_notifier_inc(void)
+{
+	static_key_slow_inc(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_inc);
+
+void preempt_notifier_dec(void)
+{
+	static_key_slow_dec(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_dec);
+
+/**
+ * preempt_notifier_register - tell me when current is being preempted & rescheduled
+ * @notifier: notifier struct to register
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+	if (!static_key_false(&preempt_notifier_key))
+		WARN(1, "registering preempt_notifier while notifiers disabled\n");
+
+	hlist_add_head(&notifier->link, &current->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ * @notifier: notifier struct to unregister
+ *
+ * This is *not* safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+	hlist_del(&notifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	if (static_key_false(&preempt_notifier_key))
+		__fire_sched_in_preempt_notifiers(curr);
+}
+
+static void
+__fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_out(notifier, next);
+}
+
+static __always_inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+	if (static_key_false(&preempt_notifier_key))
+		__fire_sched_out_preempt_notifiers(curr, next);
+}
+
+#else /* !CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+}
+
+#endif /* CONFIG_PREEMPT_NOTIFIERS */
+
+/**
+ * prepare_task_switch - prepare to switch tasks
+ * @rq: the runqueue preparing to switch
+ * @next: the task we are going to switch to.
+ *
+ * This is called with the rq lock held and interrupts off. It must
+ * be paired with a subsequent finish_task_switch after the context
+ * switch.
+ *
+ * prepare_task_switch sets up locking and calls architecture specific
+ * hooks.
+ */
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+		    struct task_struct *next)
+{
+	sched_info_switch(rq, prev, next);
+	perf_event_task_sched_out(prev, next);
+	fire_sched_out_preempt_notifiers(prev, next);
+	prepare_lock_switch(rq, next);
+	prepare_arch_switch(next);
+}
+
+/**
+ * finish_task_switch - clean up after a task-switch
+ * @rq: runqueue associated with task-switch
+ * @prev: the thread we just switched away from.
+ *
+ * finish_task_switch must be called after the context switch, paired
+ * with a prepare_task_switch call before the context switch.
+ * finish_task_switch will reconcile locking set up by prepare_task_switch,
+ * and do any other architecture-specific cleanup actions.
+ *
+ * Note that we may have delayed dropping an mm in context_switch(). If
+ * so, we finish that here outside of the runqueue lock.  (Doing it
+ * with the lock held can cause deadlocks; see schedule() for
+ * details.)
+ *
+ * The context switch have flipped the stack from under us and restored the
+ * local variables which were saved when this task called schedule() in the
+ * past. prev == current is still correct but we need to recalculate this_rq
+ * because prev may have moved to another CPU.
+ */
+static struct rq *finish_task_switch(struct task_struct *prev)
+	__releases(grq.lock)
+{
+	struct rq *rq = this_rq();
+	struct mm_struct *mm = rq->prev_mm;
+	long prev_state;
+
+	/*
+	 * The previous task will have left us with a preempt_count of 2
+	 * because it left us after:
+	 *
+	 *	schedule()
+	 *	  preempt_disable();			// 1
+	 *	  __schedule()
+	 *	    raw_spin_lock_irq(&rq->lock)	// 2
+	 *
+	 * Also, see FORK_PREEMPT_COUNT.
+	 */
+	if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
+		      "corrupted preempt_count: %s/%d/0x%x\n",
+		      current->comm, current->pid, preempt_count()))
+		preempt_count_set(FORK_PREEMPT_COUNT);
+
+	rq->prev_mm = NULL;
+
+	/*
+	 * A task struct has one reference for the use as "current".
+	 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+	 * schedule one last time. The schedule call will never return, and
+	 * the scheduled task must drop that reference.
+	 *
+	 * We must observe prev->state before clearing prev->on_cpu (in
+	 * finish_lock_switch), otherwise a concurrent wakeup can get prev
+	 * running on another CPU and we could rave with its RUNNING -> DEAD
+	 * transition, resulting in a double drop.
+	 */
+	prev_state = prev->state;
+	vtime_task_switch(prev);
+	perf_event_task_sched_in(prev, current);
+	finish_lock_switch(rq, prev);
+	finish_arch_post_lock_switch();
+
+	fire_sched_in_preempt_notifiers(current);
+	if (mm)
+		mmdrop(mm);
+	if (unlikely(prev_state == TASK_DEAD)) {
+		/*
+		 * Remove function-return probe instances associated with this
+		 * task and put them back on the free list.
+		 */
+		kprobe_flush_task(prev);
+		put_task_struct(prev);
+	}
+	return rq;
+}
+
+/**
+ * schedule_tail - first thing a freshly forked thread must call.
+ * @prev: the thread we just switched away from.
+ */
+asmlinkage __visible void schedule_tail(struct task_struct *prev)
+	__releases(grq.lock)
+{
+	struct rq *rq;
+
+	/*
+	 * New tasks start with FORK_PREEMPT_COUNT, see there and
+	 * finish_task_switch() for details.
+	 *
+	 * finish_task_switch() will drop rq->lock() and lower preempt_count
+	 * and the preempt_enable() will end up enabling preemption (on
+	 * PREEMPT_COUNT kernels).
+	 */
+
+	rq = finish_task_switch(prev);
+	preempt_enable();
+
+	if (current->set_child_tid)
+		put_user(task_pid_vnr(current), current->set_child_tid);
+}
+
+/*
+ * context_switch - switch to the new MM and the new thread's register state.
+ */
+static inline struct rq *
+context_switch(struct rq *rq, struct task_struct *prev,
+	       struct task_struct *next)
+{
+	struct mm_struct *mm, *oldmm;
+
+	prepare_task_switch(rq, prev, next);
+
+	mm = next->mm;
+	oldmm = prev->active_mm;
+	/*
+	 * For paravirt, this is coupled with an exit in switch_to to
+	 * combine the page table reload and the switch backend into
+	 * one hypercall.
+	 */
+	arch_start_context_switch(prev);
+
+	if (!mm) {
+		next->active_mm = oldmm;
+		atomic_inc(&oldmm->mm_count);
+		enter_lazy_tlb(oldmm, next);
+	} else
+		switch_mm(oldmm, mm, next);
+
+	if (!prev->mm) {
+		prev->active_mm = NULL;
+		rq->prev_mm = oldmm;
+	}
+	/*
+	 * Since the runqueue lock will be released by the next
+	 * task (which is an invalid locking op but in the case
+	 * of the scheduler it's an obvious special-case), so we
+	 * do an early lockdep release here:
+	 */
+	spin_release(&grq.lock.dep_map, 1, _THIS_IP_);
+
+	/* Here we just switch the register state and the stack. */
+	switch_to(prev, next, prev);
+	barrier();
+
+	return finish_task_switch(prev);
+}
+
+/*
+ * nr_running, nr_uninterruptible and nr_context_switches:
+ *
+ * externally visible scheduler statistics: current number of runnable
+ * threads, total number of context switches performed since bootup. All are
+ * measured without grabbing the grq lock but the occasional inaccurate result
+ * doesn't matter so long as it's positive.
+ */
+unsigned long nr_running(void)
+{
+	long nr = grq.nr_running;
+
+	if (unlikely(nr < 0))
+		nr = 0;
+	return (unsigned long)nr;
+}
+
+static unsigned long nr_uninterruptible(void)
+{
+	long nu = grq.nr_uninterruptible;
+
+	if (unlikely(nu < 0))
+		nu = 0;
+	return nu;
+}
+
+/*
+ * Check if only the current task is running on the cpu.
+ *
+ * Caution: this function does not check that the caller has disabled
+ * preemption, thus the result might have a time-of-check-to-time-of-use
+ * race.  The caller is responsible to use it correctly, for example:
+ *
+ * - from a non-preemptable section (of course)
+ *
+ * - from a thread that is bound to a single CPU
+ *
+ * - in a loop with very short iterations (e.g. a polling loop)
+ */
+bool single_task_running(void)
+{
+	if (cpu_rq(smp_processor_id())->soft_affined == 1)
+		return true;
+	else
+		return false;
+}
+EXPORT_SYMBOL(single_task_running);
+
+unsigned long long nr_context_switches(void)
+{
+	long long ns = grq.nr_switches;
+
+	/* This is of course impossible */
+	if (unlikely(ns < 0))
+		ns = 1;
+	return (unsigned long long)ns;
+}
+
+unsigned long nr_iowait(void)
+{
+	unsigned long i, sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += atomic_read(&cpu_rq(i)->nr_iowait);
+
+	return sum;
+}
+
+unsigned long nr_iowait_cpu(int cpu)
+{
+	struct rq *this = cpu_rq(cpu);
+	return atomic_read(&this->nr_iowait);
+}
+
+unsigned long nr_active(void)
+{
+	return nr_running() + nr_uninterruptible();
+}
+
+/* Beyond a task running on this CPU, load is equal everywhere on BFS, so we
+ * base it on the number of running or queued tasks with their ->rq pointer
+ * set to this cpu as being the CPU they're more likely to run on. */
+void get_iowait_load(unsigned long *nr_waiters, unsigned long *load)
+{
+	struct rq *rq = this_rq();
+
+	*nr_waiters = atomic_read(&rq->nr_iowait);
+	*load = rq->soft_affined;
+}
+
+/* Variables and functions for calc_load */
+static unsigned long calc_load_update;
+unsigned long avenrun[3];
+EXPORT_SYMBOL(avenrun);
+
+/**
+ * get_avenrun - get the load average array
+ * @loads:	pointer to dest load array
+ * @offset:	offset to add
+ * @shift:	shift count to shift the result left
+ *
+ * These values are estimates at best, so no need for locking.
+ */
+void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
+{
+	loads[0] = (avenrun[0] + offset) << shift;
+	loads[1] = (avenrun[1] + offset) << shift;
+	loads[2] = (avenrun[2] + offset) << shift;
+}
+
+static unsigned long
+calc_load(unsigned long load, unsigned long exp, unsigned long active)
+{
+	load *= exp;
+	load += active * (FIXED_1 - exp);
+	return load >> FSHIFT;
+}
+
+/*
+ * calc_load - update the avenrun load estimates every LOAD_FREQ seconds.
+ */
+void calc_global_load(unsigned long ticks)
+{
+	long active;
+
+	if (time_before(jiffies, calc_load_update))
+		return;
+	active = nr_active() * FIXED_1;
+
+	avenrun[0] = calc_load(avenrun[0], EXP_1, active);
+	avenrun[1] = calc_load(avenrun[1], EXP_5, active);
+	avenrun[2] = calc_load(avenrun[2], EXP_15, active);
+
+	calc_load_update = jiffies + LOAD_FREQ;
+}
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+
+/*
+ * There are no locks covering percpu hardirq/softirq time.
+ * They are only modified in account_system_vtime, on corresponding CPU
+ * with interrupts disabled. So, writes are safe.
+ * They are read and saved off onto struct rq in update_rq_clock().
+ * This may result in other CPU reading this CPU's irq time and can
+ * race with irq/account_system_vtime on this CPU. We would either get old
+ * or new value with a side effect of accounting a slice of irq time to wrong
+ * task when irq is in progress while we read rq->clock. That is a worthy
+ * compromise in place of having locks on each irq in account_system_time.
+ */
+static DEFINE_PER_CPU(u64, cpu_hardirq_time);
+static DEFINE_PER_CPU(u64, cpu_softirq_time);
+
+static DEFINE_PER_CPU(u64, irq_start_time);
+static int sched_clock_irqtime;
+
+void enable_sched_clock_irqtime(void)
+{
+	sched_clock_irqtime = 1;
+}
+
+void disable_sched_clock_irqtime(void)
+{
+	sched_clock_irqtime = 0;
+}
+
+#ifndef CONFIG_64BIT
+static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
+
+static inline void irq_time_write_begin(void)
+{
+	__this_cpu_inc(irq_time_seq.sequence);
+	smp_wmb();
+}
+
+static inline void irq_time_write_end(void)
+{
+	smp_wmb();
+	__this_cpu_inc(irq_time_seq.sequence);
+}
+
+static inline u64 irq_time_read(int cpu)
+{
+	u64 irq_time;
+	unsigned seq;
+
+	do {
+		seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
+		irq_time = per_cpu(cpu_softirq_time, cpu) +
+			   per_cpu(cpu_hardirq_time, cpu);
+	} while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
+
+	return irq_time;
+}
+#else /* CONFIG_64BIT */
+static inline void irq_time_write_begin(void)
+{
+}
+
+static inline void irq_time_write_end(void)
+{
+}
+
+static inline u64 irq_time_read(int cpu)
+{
+	return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
+}
+#endif /* CONFIG_64BIT */
+
+/*
+ * Called before incrementing preempt_count on {soft,}irq_enter
+ * and before decrementing preempt_count on {soft,}irq_exit.
+ */
+void irqtime_account_irq(struct task_struct *curr)
+{
+	unsigned long flags;
+	s64 delta;
+	int cpu;
+
+	if (!sched_clock_irqtime)
+		return;
+
+	local_irq_save(flags);
+
+	cpu = smp_processor_id();
+	delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
+	__this_cpu_add(irq_start_time, delta);
+
+	irq_time_write_begin();
+	/*
+	 * We do not account for softirq time from ksoftirqd here.
+	 * We want to continue accounting softirq time to ksoftirqd thread
+	 * in that case, so as not to confuse scheduler with a special task
+	 * that do not consume any time, but still wants to run.
+	 */
+	if (hardirq_count())
+		__this_cpu_add(cpu_hardirq_time, delta);
+	else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
+		__this_cpu_add(cpu_softirq_time, delta);
+
+	irq_time_write_end();
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(irqtime_account_irq);
+
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#ifdef CONFIG_PARAVIRT
+static inline u64 steal_ticks(u64 steal)
+{
+	if (unlikely(steal > NSEC_PER_SEC))
+		return div_u64(steal, TICK_NSEC);
+
+	return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
+}
+#endif
+
+static void update_rq_clock_task(struct rq *rq, s64 delta)
+{
+/*
+ * In theory, the compile should just see 0 here, and optimize out the call
+ * to sched_rt_avg_update. But I don't trust it...
+ */
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	s64 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
+
+	/*
+	 * Since irq_time is only updated on {soft,}irq_exit, we might run into
+	 * this case when a previous update_rq_clock() happened inside a
+	 * {soft,}irq region.
+	 *
+	 * When this happens, we stop ->clock_task and only update the
+	 * prev_irq_time stamp to account for the part that fit, so that a next
+	 * update will consume the rest. This ensures ->clock_task is
+	 * monotonic.
+	 *
+	 * It does however cause some slight miss-attribution of {soft,}irq
+	 * time, a more accurate solution would be to update the irq_time using
+	 * the current rq->clock timestamp, except that would require using
+	 * atomic ops.
+	 */
+	if (irq_delta > delta)
+		irq_delta = delta;
+
+	rq->prev_irq_time += irq_delta;
+	delta -= irq_delta;
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	if (static_key_false((&paravirt_steal_rq_enabled))) {
+		s64 steal = paravirt_steal_clock(cpu_of(rq));
+
+		steal -= rq->prev_steal_time_rq;
+
+		if (unlikely(steal > delta))
+			steal = delta;
+
+		rq->prev_steal_time_rq += steal;
+
+		delta -= steal;
+	}
+#endif
+
+	rq->clock_task += delta;
+}
+
+#ifndef nsecs_to_cputime
+# define nsecs_to_cputime(__nsecs)	nsecs_to_jiffies(__nsecs)
+#endif
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+static void irqtime_account_hi_si(void)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	u64 latest_ns;
+
+	latest_ns = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time));
+	if (latest_ns > cpustat[CPUTIME_IRQ])
+		cpustat[CPUTIME_IRQ] += (__force u64)cputime_one_jiffy;
+
+	latest_ns = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time));
+	if (latest_ns > cpustat[CPUTIME_SOFTIRQ])
+		cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy;
+}
+#else /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#define sched_clock_irqtime	(0)
+
+static inline void irqtime_account_hi_si(void)
+{
+}
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+static __always_inline bool steal_account_process_tick(void)
+{
+#ifdef CONFIG_PARAVIRT
+	if (static_key_false(&paravirt_steal_enabled)) {
+		u64 steal;
+		cputime_t steal_ct;
+
+		steal = paravirt_steal_clock(smp_processor_id());
+		steal -= this_rq()->prev_steal_time;
+
+		/*
+		 * cputime_t may be less precise than nsecs (eg: if it's
+		 * based on jiffies). Lets cast the result to cputime
+		 * granularity and account the rest on the next rounds.
+		 */
+		steal_ct = nsecs_to_cputime(steal);
+		this_rq()->prev_steal_time += cputime_to_nsecs(steal_ct);
+
+		account_steal_time(steal_ct);
+		return steal_ct;
+	}
+#endif
+	return false;
+}
+
+/*
+ * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
+ * tasks (sum on group iteration) belonging to @tsk's group.
+ */
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
+{
+	struct signal_struct *sig = tsk->signal;
+	cputime_t utime, stime;
+	struct task_struct *t;
+	unsigned int seq, nextseq;
+	unsigned long flags;
+
+	rcu_read_lock();
+	/* Attempt a lockless read on the first round. */
+	nextseq = 0;
+	do {
+		seq = nextseq;
+		flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
+		times->utime = sig->utime;
+		times->stime = sig->stime;
+		times->sum_exec_runtime = sig->sum_sched_runtime;
+
+		for_each_thread(tsk, t) {
+			task_cputime(t, &utime, &stime);
+			times->utime += utime;
+			times->stime += stime;
+			times->sum_exec_runtime += task_sched_runtime(t);
+		}
+		/* If lockless access failed, take the lock. */
+		nextseq = 1;
+	} while (need_seqretry(&sig->stats_lock, seq));
+	done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
+	rcu_read_unlock();
+}
+
+/*
+ * On each tick, see what percentage of that tick was attributed to each
+ * component and add the percentage to the _pc values. Once a _pc value has
+ * accumulated one tick's worth, account for that. This means the total
+ * percentage of load components will always be 128 (pseudo 100) per tick.
+ */
+static void pc_idle_time(struct rq *rq, struct task_struct *idle, unsigned long pc)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	if (atomic_read(&rq->nr_iowait) > 0) {
+		rq->iowait_pc += pc;
+		if (rq->iowait_pc >= 128) {
+			cpustat[CPUTIME_IOWAIT] += (__force u64)cputime_one_jiffy * rq->iowait_pc / 128;
+			rq->iowait_pc %= 128;
+		}
+	} else {
+		rq->idle_pc += pc;
+		if (rq->idle_pc >= 128) {
+			cpustat[CPUTIME_IDLE] += (__force u64)cputime_one_jiffy * rq->idle_pc / 128;
+			rq->idle_pc %= 128;
+		}
+	}
+	acct_update_integrals(idle);
+}
+
+static void
+pc_system_time(struct rq *rq, struct task_struct *p, int hardirq_offset,
+	       unsigned long pc, unsigned long ns)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
+
+	p->stime_pc += pc;
+	if (p->stime_pc >= 128) {
+		int jiffs = p->stime_pc / 128;
+
+		p->stime_pc %= 128;
+		p->stime += (__force u64)cputime_one_jiffy * jiffs;
+		p->stimescaled += one_jiffy_scaled * jiffs;
+		account_group_system_time(p, cputime_one_jiffy * jiffs);
+	}
+	p->sched_time += ns;
+	account_group_exec_runtime(p, ns);
+
+	if (hardirq_count() - hardirq_offset) {
+		rq->irq_pc += pc;
+		if (rq->irq_pc >= 128) {
+			cpustat[CPUTIME_IRQ] += (__force u64)cputime_one_jiffy * rq->irq_pc / 128;
+			rq->irq_pc %= 128;
+		}
+	} else if (in_serving_softirq()) {
+		rq->softirq_pc += pc;
+		if (rq->softirq_pc >= 128) {
+			cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy * rq->softirq_pc / 128;
+			rq->softirq_pc %= 128;
+		}
+	} else {
+		rq->system_pc += pc;
+		if (rq->system_pc >= 128) {
+			cpustat[CPUTIME_SYSTEM] += (__force u64)cputime_one_jiffy * rq->system_pc / 128;
+			rq->system_pc %= 128;
+		}
+	}
+	acct_update_integrals(p);
+}
+
+static void pc_user_time(struct rq *rq, struct task_struct *p,
+			 unsigned long pc, unsigned long ns)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
+
+	p->utime_pc += pc;
+	if (p->utime_pc >= 128) {
+		int jiffs = p->utime_pc / 128;
+
+		p->utime_pc %= 128;
+		p->utime += (__force u64)cputime_one_jiffy * jiffs;
+		p->utimescaled += one_jiffy_scaled * jiffs;
+		account_group_user_time(p, cputime_one_jiffy * jiffs);
+	}
+	p->sched_time += ns;
+	account_group_exec_runtime(p, ns);
+
+	if (this_cpu_ksoftirqd() == p) {
+		/*
+		 * ksoftirqd time do not get accounted in cpu_softirq_time.
+		 * So, we have to handle it separately here.
+		 */
+		rq->softirq_pc += pc;
+		if (rq->softirq_pc >= 128) {
+			cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy * rq->softirq_pc / 128;
+			rq->softirq_pc %= 128;
+		}
+	}
+
+	if (task_nice(p) > 0 || idleprio_task(p)) {
+		rq->nice_pc += pc;
+		if (rq->nice_pc >= 128) {
+			cpustat[CPUTIME_NICE] += (__force u64)cputime_one_jiffy * rq->nice_pc / 128;
+			rq->nice_pc %= 128;
+		}
+	} else {
+		rq->user_pc += pc;
+		if (rq->user_pc >= 128) {
+			cpustat[CPUTIME_USER] += (__force u64)cputime_one_jiffy * rq->user_pc / 128;
+			rq->user_pc %= 128;
+		}
+	}
+	acct_update_integrals(p);
+}
+
+/*
+ * Convert nanoseconds to pseudo percentage of one tick. Use 128 for fast
+ * shifts instead of 100
+ */
+#define NS_TO_PC(NS)	(NS * 128 / JIFFY_NS)
+
+/*
+ * This is called on clock ticks.
+ * Bank in p->sched_time the ns elapsed since the last tick or switch.
+ * CPU scheduler quota accounting is also performed here in microseconds.
+ */
+static void
+update_cpu_clock_tick(struct rq *rq, struct task_struct *p)
+{
+	long account_ns = rq->clock_task - rq->rq_last_ran;
+	struct task_struct *idle = rq->idle;
+	unsigned long account_pc;
+
+	if (unlikely(account_ns < 0) || steal_account_process_tick())
+		goto ts_account;
+
+	account_pc = NS_TO_PC(account_ns);
+
+	/* Accurate tick timekeeping */
+	if (user_mode(get_irq_regs()))
+		pc_user_time(rq, p, account_pc, account_ns);
+	else if (p != idle || (irq_count() != HARDIRQ_OFFSET))
+		pc_system_time(rq, p, HARDIRQ_OFFSET,
+			       account_pc, account_ns);
+	else
+		pc_idle_time(rq, idle, account_pc);
+
+	if (sched_clock_irqtime)
+		irqtime_account_hi_si();
+
+ts_account:
+	/* time_slice accounting is done in usecs to avoid overflow on 32bit */
+	if (rq->rq_policy != SCHED_FIFO && p != idle) {
+		s64 time_diff = rq->clock - rq->timekeep_clock;
+
+		niffy_diff(&time_diff, 1);
+		rq->rq_time_slice -= NS_TO_US(time_diff);
+	}
+
+	rq->rq_last_ran = rq->clock_task;
+	rq->timekeep_clock = rq->clock;
+}
+
+/*
+ * This is called on context switches.
+ * Bank in p->sched_time the ns elapsed since the last tick or switch.
+ * CPU scheduler quota accounting is also performed here in microseconds.
+ */
+static void
+update_cpu_clock_switch(struct rq *rq, struct task_struct *p)
+{
+	long account_ns = rq->clock_task - rq->rq_last_ran;
+	struct task_struct *idle = rq->idle;
+	unsigned long account_pc;
+
+	if (unlikely(account_ns < 0))
+		goto ts_account;
+
+	account_pc = NS_TO_PC(account_ns);
+
+	/* Accurate subtick timekeeping */
+	if (p != idle) {
+		pc_user_time(rq, p, account_pc, account_ns);
+	}
+	else
+		pc_idle_time(rq, idle, account_pc);
+
+ts_account:
+	/* time_slice accounting is done in usecs to avoid overflow on 32bit */
+	if (rq->rq_policy != SCHED_FIFO && p != idle) {
+		s64 time_diff = rq->clock - rq->timekeep_clock;
+
+		niffy_diff(&time_diff, 1);
+		rq->rq_time_slice -= NS_TO_US(time_diff);
+	}
+
+	rq->rq_last_ran = rq->clock_task;
+	rq->timekeep_clock = rq->clock;
+}
+
+/*
+ * Return any ns on the sched_clock that have not yet been accounted in
+ * @p in case that task is currently running.
+ *
+ * Called with task_grq_lock() held.
+ */
+static inline u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
+{
+	u64 ns = 0;
+
+	/*
+	 * Must be ->curr _and_ ->on_rq.  If dequeued, we would
+	 * project cycles that may never be accounted to this
+	 * thread, breaking clock_gettime().
+	 */
+	if (p == rq->curr && p->on_rq) {
+		update_clocks(rq);
+		ns = rq->clock_task - rq->rq_last_ran;
+		if (unlikely((s64)ns < 0))
+			ns = 0;
+	}
+
+	return ns;
+}
+
+/*
+ * Return accounted runtime for the task.
+ * Return separately the current's pending runtime that have not been
+ * accounted yet.
+ *
+ */
+unsigned long long task_sched_runtime(struct task_struct *p)
+{
+	unsigned long flags;
+	struct rq *rq;
+	u64 ns;
+
+#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
+	/*
+	 * 64-bit doesn't need locks to atomically read a 64bit value.
+	 * So we have a optimization chance when the task's delta_exec is 0.
+	 * Reading ->on_cpu is racy, but this is ok.
+	 *
+	 * If we race with it leaving cpu, we'll take a lock. So we're correct.
+	 * If we race with it entering cpu, unaccounted time is 0. This is
+	 * indistinguishable from the read occurring a few cycles earlier.
+	 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
+	 * been accounted, so we're correct here as well.
+	 */
+	if (!p->on_cpu || !p->on_rq)
+		return tsk_seruntime(p);
+#endif
+
+	rq = task_grq_lock(p, &flags);
+	ns = p->sched_time + do_task_delta_exec(p, rq);
+	task_grq_unlock(&flags);
+
+	return ns;
+}
+
+/* Compatibility crap */
+void account_user_time(struct task_struct *p, cputime_t cputime,
+		       cputime_t cputime_scaled)
+{
+}
+
+void account_idle_time(cputime_t cputime)
+{
+}
+
+/*
+ * Account guest cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @cputime: the cpu time spent in virtual machine since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
+ */
+static void account_guest_time(struct task_struct *p, cputime_t cputime,
+			       cputime_t cputime_scaled)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	/* Add guest time to process. */
+	p->utime += (__force u64)cputime;
+	p->utimescaled += (__force u64)cputime_scaled;
+	account_group_user_time(p, cputime);
+	p->gtime += (__force u64)cputime;
+
+	/* Add guest time to cpustat. */
+	if (task_nice(p) > 0) {
+		cpustat[CPUTIME_NICE] += (__force u64)cputime;
+		cpustat[CPUTIME_GUEST_NICE] += (__force u64)cputime;
+	} else {
+		cpustat[CPUTIME_USER] += (__force u64)cputime;
+		cpustat[CPUTIME_GUEST] += (__force u64)cputime;
+	}
+}
+
+/*
+ * Account system cpu time to a process and desired cpustat field
+ * @p: the process that the cpu time gets accounted to
+ * @cputime: the cpu time spent in kernel space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
+ * @target_cputime64: pointer to cpustat field that has to be updated
+ */
+static inline
+void __account_system_time(struct task_struct *p, cputime_t cputime,
+			cputime_t cputime_scaled, cputime64_t *target_cputime64)
+{
+	/* Add system time to process. */
+	p->stime += (__force u64)cputime;
+	p->stimescaled += (__force u64)cputime_scaled;
+	account_group_system_time(p, cputime);
+
+	/* Add system time to cpustat. */
+	*target_cputime64 += (__force u64)cputime;
+
+	/* Account for system time used */
+	acct_update_integrals(p);
+}
+
+/*
+ * Account system cpu time to a process.
+ * @p: the process that the cpu time gets accounted to
+ * @hardirq_offset: the offset to subtract from hardirq_count()
+ * @cputime: the cpu time spent in kernel space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
+ * This is for guest only now.
+ */
+void account_system_time(struct task_struct *p, int hardirq_offset,
+			 cputime_t cputime, cputime_t cputime_scaled)
+{
+
+	if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0))
+		account_guest_time(p, cputime, cputime_scaled);
+}
+
+/*
+ * Account for involuntary wait time.
+ * @steal: the cpu time spent in involuntary wait
+ */
+void account_steal_time(cputime_t cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+
+	cpustat[CPUTIME_STEAL] += (__force u64)cputime;
+}
+
+/*
+ * Account for idle time.
+ * @cputime: the cpu time spent in idle wait
+ */
+static void account_idle_times(cputime_t cputime)
+{
+	u64 *cpustat = kcpustat_this_cpu->cpustat;
+	struct rq *rq = this_rq();
+
+	if (atomic_read(&rq->nr_iowait) > 0)
+		cpustat[CPUTIME_IOWAIT] += (__force u64)cputime;
+	else
+		cpustat[CPUTIME_IDLE] += (__force u64)cputime;
+}
+
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+
+void account_process_tick(struct task_struct *p, int user_tick)
+{
+}
+
+/*
+ * Account multiple ticks of steal time.
+ * @p: the process from which the cpu time has been stolen
+ * @ticks: number of stolen ticks
+ */
+void account_steal_ticks(unsigned long ticks)
+{
+	account_steal_time(jiffies_to_cputime(ticks));
+}
+
+/*
+ * Account multiple ticks of idle time.
+ * @ticks: number of stolen ticks
+ */
+void account_idle_ticks(unsigned long ticks)
+{
+	account_idle_times(jiffies_to_cputime(ticks));
+}
+#endif
+
+static inline void grq_iso_lock(void)
+	__acquires(grq.iso_lock)
+{
+	raw_spin_lock(&grq.iso_lock);
+}
+
+static inline void grq_iso_unlock(void)
+	__releases(grq.iso_lock)
+{
+	raw_spin_unlock(&grq.iso_lock);
+}
+
+/*
+ * Functions to test for when SCHED_ISO tasks have used their allocated
+ * quota as real time scheduling and convert them back to SCHED_NORMAL.
+ * Where possible, the data is tested lockless, to avoid grabbing iso_lock
+ * because the occasional inaccurate result won't matter. However the
+ * tick data is only ever modified under lock. iso_refractory is only simply
+ * set to 0 or 1 so it's not worth grabbing the lock yet again for that.
+ */
+static bool set_iso_refractory(void)
+{
+	grq.iso_refractory = true;
+	return grq.iso_refractory;
+}
+
+static bool clear_iso_refractory(void)
+{
+	grq.iso_refractory = false;
+	return grq.iso_refractory;
+}
+
+/*
+ * Test if SCHED_ISO tasks have run longer than their alloted period as RT
+ * tasks and set the refractory flag if necessary. There is 10% hysteresis
+ * for unsetting the flag. 115/128 is ~90/100 as a fast shift instead of a
+ * slow division.
+ */
+static bool test_ret_isorefractory(struct rq *rq)
+{
+	if (likely(!grq.iso_refractory)) {
+		if (grq.iso_ticks > ISO_PERIOD * sched_iso_cpu)
+			return set_iso_refractory();
+	} else {
+		if (grq.iso_ticks < ISO_PERIOD * (sched_iso_cpu * 115 / 128))
+			return clear_iso_refractory();
+	}
+	return grq.iso_refractory;
+}
+
+static void iso_tick(void)
+{
+	grq_iso_lock();
+	grq.iso_ticks += 100;
+	grq_iso_unlock();
+}
+
+/* No SCHED_ISO task was running so decrease rq->iso_ticks */
+static inline void no_iso_tick(void)
+{
+	if (grq.iso_ticks) {
+		grq_iso_lock();
+		grq.iso_ticks -= grq.iso_ticks / ISO_PERIOD + 1;
+		if (unlikely(grq.iso_refractory && grq.iso_ticks <
+		    ISO_PERIOD * (sched_iso_cpu * 115 / 128)))
+			clear_iso_refractory();
+		grq_iso_unlock();
+	}
+}
+
+/* This manages tasks that have run out of timeslice during a scheduler_tick */
+static void task_running_tick(struct rq *rq)
+{
+	struct task_struct *p;
+
+	/*
+	 * If a SCHED_ISO task is running we increment the iso_ticks. In
+	 * order to prevent SCHED_ISO tasks from causing starvation in the
+	 * presence of true RT tasks we account those as iso_ticks as well.
+	 */
+	if ((rt_queue(rq) || (iso_queue(rq) && !grq.iso_refractory))) {
+		if (grq.iso_ticks <= (ISO_PERIOD * 128) - 128)
+			iso_tick();
+	} else
+		no_iso_tick();
+
+	if (iso_queue(rq)) {
+		if (unlikely(test_ret_isorefractory(rq))) {
+			if (rq_running_iso(rq)) {
+				/*
+				 * SCHED_ISO task is running as RT and limit
+				 * has been hit. Force it to reschedule as
+				 * SCHED_NORMAL by zeroing its time_slice
+				 */
+				rq->rq_time_slice = 0;
+			}
+		}
+	}
+
+	/* SCHED_FIFO tasks never run out of timeslice. */
+	if (rq->rq_policy == SCHED_FIFO)
+		return;
+	/*
+	 * Tasks that were scheduled in the first half of a tick are not
+	 * allowed to run into the 2nd half of the next tick if they will
+	 * run out of time slice in the interim. Otherwise, if they have
+	 * less than RESCHED_US μs of time slice left they will be rescheduled.
+	 */
+	if (rq->dither) {
+		if (rq->rq_time_slice > HALF_JIFFY_US)
+			return;
+		else
+			rq->rq_time_slice = 0;
+	} else if (rq->rq_time_slice >= RESCHED_US)
+			return;
+
+	/* p->time_slice < RESCHED_US. We only modify task_struct under grq lock */
+	p = rq->curr;
+
+	grq_lock();
+	requeue_task(p);
+	__set_tsk_resched(p);
+	grq_unlock();
+}
+
+/*
+ * This function gets called by the timer code, with HZ frequency.
+ * We call it with interrupts disabled. The data modified is all
+ * local to struct rq so we don't need to grab grq lock.
+ */
+void scheduler_tick(void)
+{
+	int cpu __maybe_unused = smp_processor_id();
+	struct rq *rq = cpu_rq(cpu);
+
+	sched_clock_tick();
+	/* grq lock not grabbed, so only update rq clock */
+	update_rq_clock(rq);
+	update_cpu_clock_tick(rq, rq->curr);
+	if (!rq_idle(rq))
+		task_running_tick(rq);
+	else
+		no_iso_tick();
+	rq->last_tick = rq->clock;
+	perf_event_task_tick();
+}
+
+notrace unsigned long get_parent_ip(unsigned long addr)
+{
+	if (in_lock_functions(addr)) {
+		addr = CALLER_ADDR2;
+		if (in_lock_functions(addr))
+			addr = CALLER_ADDR3;
+	}
+	return addr;
+}
+
+#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
+				defined(CONFIG_PREEMPT_TRACER))
+void preempt_count_add(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+		return;
+#endif
+	__preempt_count_add(val);
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Spinlock count overflowing soon?
+	 */
+	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
+				PREEMPT_MASK - 10);
+#endif
+	if (preempt_count() == val) {
+		unsigned long ip = get_parent_ip(CALLER_ADDR1);
+#ifdef CONFIG_DEBUG_PREEMPT
+		current->preempt_disable_ip = ip;
+#endif
+		trace_preempt_off(CALLER_ADDR0, ip);
+	}
+}
+EXPORT_SYMBOL(preempt_count_add);
+NOKPROBE_SYMBOL(preempt_count_add);
+
+void preempt_count_sub(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+		return;
+	/*
+	 * Is the spinlock portion underflowing?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+			!(preempt_count() & PREEMPT_MASK)))
+		return;
+#endif
+
+	if (preempt_count() == val)
+		trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+	__preempt_count_sub(val);
+}
+EXPORT_SYMBOL(preempt_count_sub);
+NOKPROBE_SYMBOL(preempt_count_sub);
+#endif
+
+/*
+ * Deadline is "now" in niffies + (offset by priority). Setting the deadline
+ * is the key to everything. It distributes cpu fairly amongst tasks of the
+ * same nice value, it proportions cpu according to nice level, it means the
+ * task that last woke up the longest ago has the earliest deadline, thus
+ * ensuring that interactive tasks get low latency on wake up. The CPU
+ * proportion works out to the square of the virtual deadline difference, so
+ * this equation will give nice 19 3% CPU compared to nice 0.
+ */
+static inline u64 prio_deadline_diff(int user_prio)
+{
+	return (prio_ratios[user_prio] * rr_interval * (MS_TO_NS(1) / 128));
+}
+
+static inline u64 task_deadline_diff(struct task_struct *p)
+{
+	return prio_deadline_diff(TASK_USER_PRIO(p));
+}
+
+static inline u64 static_deadline_diff(int static_prio)
+{
+	return prio_deadline_diff(USER_PRIO(static_prio));
+}
+
+static inline int longest_deadline_diff(void)
+{
+	return prio_deadline_diff(39);
+}
+
+static inline int ms_longest_deadline_diff(void)
+{
+	return NS_TO_MS(longest_deadline_diff());
+}
+
+/*
+ * The time_slice is only refilled when it is empty and that is when we set a
+ * new deadline.
+ */
+static void time_slice_expired(struct task_struct *p)
+{
+	p->time_slice = timeslice();
+	p->deadline = grq.niffies + task_deadline_diff(p);
+#ifdef CONFIG_SMT_NICE
+	if (!p->mm)
+		p->smt_bias = 0;
+	else if (rt_task(p))
+		p->smt_bias = 1 << 30;
+	else if (task_running_iso(p))
+		p->smt_bias = 1 << 29;
+	else if (idleprio_task(p)) {
+		if (task_running_idle(p))
+			p->smt_bias = 0;
+		else
+			p->smt_bias = 1;
+	} else if (--p->smt_bias < 1)
+		p->smt_bias = MAX_PRIO - p->static_prio;
+#endif
+}
+
+/*
+ * Timeslices below RESCHED_US are considered as good as expired as there's no
+ * point rescheduling when there's so little time left. SCHED_BATCH tasks
+ * have been flagged be not latency sensitive and likely to be fully CPU
+ * bound so every time they're rescheduled they have their time_slice
+ * refilled, but get a new later deadline to have little effect on
+ * SCHED_NORMAL tasks.
+
+ */
+static inline void check_deadline(struct task_struct *p)
+{
+	if (p->time_slice < RESCHED_US || batch_task(p))
+		time_slice_expired(p);
+}
+
+#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
+
+/*
+ * Scheduler queue bitmap specific find next bit.
+ */
+static inline unsigned long
+next_sched_bit(const unsigned long *addr, unsigned long offset)
+{
+	const unsigned long *p;
+	unsigned long result;
+	unsigned long size;
+	unsigned long tmp;
+
+	size = PRIO_LIMIT;
+	if (offset >= size)
+		return size;
+
+	p = addr + BITOP_WORD(offset);
+	result = offset & ~(BITS_PER_LONG-1);
+	size -= result;
+	offset %= BITS_PER_LONG;
+	if (offset) {
+		tmp = *(p++);
+		tmp &= (~0UL << offset);
+		if (size < BITS_PER_LONG)
+			goto found_first;
+		if (tmp)
+			goto found_middle;
+		size -= BITS_PER_LONG;
+		result += BITS_PER_LONG;
+	}
+	while (size & ~(BITS_PER_LONG-1)) {
+		if ((tmp = *(p++)))
+			goto found_middle;
+		result += BITS_PER_LONG;
+		size -= BITS_PER_LONG;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+
+found_first:
+	tmp &= (~0UL >> (BITS_PER_LONG - size));
+	if (tmp == 0UL)		/* Are any bits set? */
+		return result + size;	/* Nope. */
+found_middle:
+	return result + __ffs(tmp);
+}
+
+/*
+ * O(n) lookup of all tasks in the global runqueue. The real brainfuck
+ * of lock contention and O(n). It's not really O(n) as only the queued,
+ * but not running tasks are scanned, and is O(n) queued in the worst case
+ * scenario only because the right task can be found before scanning all of
+ * them.
+ * Tasks are selected in this order:
+ * Real time tasks are selected purely by their static priority and in the
+ * order they were queued, so the lowest value idx, and the first queued task
+ * of that priority value is chosen.
+ * If no real time tasks are found, the SCHED_ISO priority is checked, and
+ * all SCHED_ISO tasks have the same priority value, so they're selected by
+ * the earliest deadline value.
+ * If no SCHED_ISO tasks are found, SCHED_NORMAL tasks are selected by the
+ * earliest deadline.
+ * Finally if no SCHED_NORMAL tasks are found, SCHED_IDLEPRIO tasks are
+ * selected by the earliest deadline.
+ */
+static inline struct
+task_struct *earliest_deadline_task(struct rq *rq, int cpu, struct task_struct *idle)
+{
+	struct task_struct *edt = NULL;
+	unsigned long idx = -1;
+
+	do {
+		struct list_head *queue;
+		struct task_struct *p;
+		u64 earliest_deadline;
+
+		idx = next_sched_bit(grq.prio_bitmap, ++idx);
+		if (idx >= PRIO_LIMIT)
+			return idle;
+		queue = grq.queue + idx;
+
+		if (idx < MAX_RT_PRIO) {
+			/* We found an rt task */
+			list_for_each_entry(p, queue, run_list) {
+				/* Make sure cpu affinity is ok */
+				if (needs_other_cpu(p, cpu))
+					continue;
+				edt = p;
+				goto out_take;
+			}
+			/*
+			 * None of the RT tasks at this priority can run on
+			 * this cpu
+			 */
+			continue;
+		}
+
+		/*
+		 * No rt tasks. Find the earliest deadline task. Now we're in
+		 * O(n) territory.
+		 */
+		earliest_deadline = ~0ULL;
+		list_for_each_entry(p, queue, run_list) {
+			u64 dl;
+
+			/* Make sure cpu affinity is ok */
+			if (needs_other_cpu(p, cpu))
+				continue;
+
+#ifdef CONFIG_SMT_NICE
+			if (!smt_should_schedule(p, cpu))
+				continue;
+#endif
+			/*
+			 * Soft affinity happens here by not scheduling a task
+			 * with its sticky flag set that ran on a different CPU
+			 * last when the CPU is scaling, or by greatly biasing
+			 * against its deadline when not, based on cpu cache
+			 * locality.
+			 */
+			if (sched_interactive)
+				dl = p->deadline;
+			else {
+				int tcpu = task_cpu(p);
+
+				if (tcpu != cpu && task_sticky(p) && scaling_rq(rq))
+					continue;
+				dl = p->deadline << locality_diff(tcpu, rq);
+			}
+
+			if (deadline_before(dl, earliest_deadline)) {
+				earliest_deadline = dl;
+				edt = p;
+			}
+		}
+	} while (!edt);
+
+out_take:
+	take_task(cpu, edt);
+	return edt;
+}
+
+
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
+{
+	if (oops_in_progress)
+		return;
+
+	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+		prev->comm, prev->pid, preempt_count());
+
+	debug_show_held_locks(prev);
+	print_modules();
+	if (irqs_disabled())
+		print_irqtrace_events(prev);
+#ifdef CONFIG_DEBUG_PREEMPT
+	if (in_atomic_preempt_off()) {
+		pr_err("Preemption disabled at:");
+		print_ip_sym(current->preempt_disable_ip);
+		pr_cont("\n");
+	}
+#endif
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+
+/*
+ * Various schedule()-time debugging checks and statistics:
+ */
+static inline void schedule_debug(struct task_struct *prev)
+{
+#ifdef CONFIG_SCHED_STACK_END_CHECK
+	BUG_ON(task_stack_end_corrupted(prev));
+#endif
+
+	if (unlikely(in_atomic_preempt_off())) {
+		__schedule_bug(prev);
+		preempt_count_set(PREEMPT_DISABLED);
+	}
+	rcu_sleep_check();
+
+	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+	schedstat_inc(this_rq(), sched_count);
+}
+
+/*
+ * The currently running task's information is all stored in rq local data
+ * which is only modified by the local CPU, thereby allowing the data to be
+ * changed without grabbing the grq lock.
+ */
+static inline void set_rq_task(struct rq *rq, struct task_struct *p)
+{
+	rq->rq_time_slice = p->time_slice;
+	rq->rq_deadline = p->deadline;
+	rq->rq_last_ran = p->last_ran = rq->clock_task;
+	rq->rq_policy = p->policy;
+	rq->rq_prio = p->prio;
+#ifdef CONFIG_SMT_NICE
+	rq->rq_mm = p->mm;
+	rq->rq_smt_bias = p->smt_bias;
+#endif
+	if (p != rq->idle)
+		rq->rq_running = true;
+	else
+		rq->rq_running = false;
+}
+
+static void reset_rq_task(struct rq *rq, struct task_struct *p)
+{
+	rq->rq_policy = p->policy;
+	rq->rq_prio = p->prio;
+#ifdef CONFIG_SMT_NICE
+	rq->rq_smt_bias = p->smt_bias;
+#endif
+}
+
+#ifdef CONFIG_SMT_NICE
+/* Iterate over smt siblings when we've scheduled a process on cpu and decide
+ * whether they should continue running or be descheduled. */
+static void check_smt_siblings(int cpu)
+{
+	int other_cpu;
+
+	for_each_cpu(other_cpu, thread_cpumask(cpu)) {
+		struct task_struct *p;
+		struct rq *rq;
+
+		if (other_cpu == cpu)
+			continue;
+		rq = cpu_rq(other_cpu);
+		if (rq_idle(rq))
+			continue;
+		if (!rq->online)
+			continue;
+		p = rq->curr;
+		if (!smt_should_schedule(p, cpu)) {
+			set_tsk_need_resched(p);
+			smp_send_reschedule(other_cpu);
+		}
+	}
+}
+
+static void wake_smt_siblings(int cpu)
+{
+	int other_cpu;
+
+	if (!queued_notrunning())
+		return;
+
+	for_each_cpu(other_cpu, thread_cpumask(cpu)) {
+		struct rq *rq;
+
+		if (other_cpu == cpu)
+			continue;
+		rq = cpu_rq(other_cpu);
+		if (rq_idle(rq)) {
+			struct task_struct *p = rq->curr;
+
+			set_tsk_need_resched(p);
+			smp_send_reschedule(other_cpu);
+		}
+	}
+}
+#else
+static void check_smt_siblings(int __maybe_unused cpu) {}
+static void wake_smt_siblings(int __maybe_unused cpu) {}
+#endif
+
+/*
+ * schedule() is the main scheduler function.
+ *
+ * The main means of driving the scheduler and thus entering this function are:
+ *
+ *   1. Explicit blocking: mutex, semaphore, waitqueue, etc.
+ *
+ *   2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
+ *      paths. For example, see arch/x86/entry_64.S.
+ *
+ *      To drive preemption between tasks, the scheduler sets the flag in timer
+ *      interrupt handler scheduler_tick().
+ *
+ *   3. Wakeups don't really cause entry into schedule(). They add a
+ *      task to the run-queue and that's it.
+ *
+ *      Now, if the new task added to the run-queue preempts the current
+ *      task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
+ *      called on the nearest possible occasion:
+ *
+ *       - If the kernel is preemptible (CONFIG_PREEMPT=y):
+ *
+ *         - in syscall or exception context, at the next outmost
+ *           preempt_enable(). (this might be as soon as the wake_up()'s
+ *           spin_unlock()!)
+ *
+ *         - in IRQ context, return from interrupt-handler to
+ *           preemptible context
+ *
+ *       - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
+ *         then at the next:
+ *
+ *          - cond_resched() call
+ *          - explicit schedule() call
+ *          - return from syscall or exception to user-space
+ *          - return from interrupt-handler to user-space
+ *
+ * WARNING: must be called with preemption disabled!
+ */
+static void __sched notrace __schedule(bool preempt)
+{
+	struct task_struct *prev, *next, *idle;
+	unsigned long *switch_count;
+	bool deactivate = false;
+	struct rq *rq;
+	int cpu;
+
+	cpu = smp_processor_id();
+	rq = cpu_rq(cpu);
+	prev = rq->curr;
+
+	/*
+	 * do_exit() calls schedule() with preemption disabled as an exception;
+	 * however we must fix that up, otherwise the next task will see an
+	 * inconsistent (higher) preempt count.
+	 *
+	 * It also avoids the below schedule_debug() test from complaining
+	 * about this.
+	 */
+	if (unlikely(prev->state == TASK_DEAD))
+		preempt_enable_no_resched_notrace();
+
+	schedule_debug(prev);
+
+	local_irq_disable();
+	rcu_note_context_switch();
+
+	/*
+	 * Make sure that signal_pending_state()->signal_pending() below
+	 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
+	 * done by the caller to avoid the race with signal_wake_up().
+	 */
+	smp_mb__before_spinlock();
+	grq_lock();
+
+	switch_count = &prev->nivcsw;
+	if (!preempt && prev->state) {
+		if (unlikely(signal_pending_state(prev->state, prev))) {
+			prev->state = TASK_RUNNING;
+		} else {
+			deactivate = true;
+			prev->on_rq = 0;
+
+			/*
+			 * If a worker is going to sleep, notify and
+			 * ask workqueue whether it wants to wake up a
+			 * task to maintain concurrency.  If so, wake
+			 * up the task.
+			 */
+			if (prev->flags & PF_WQ_WORKER) {
+				struct task_struct *to_wakeup;
+
+				to_wakeup = wq_worker_sleeping(prev, cpu);
+				if (to_wakeup) {
+					/* This shouldn't happen, but does */
+					if (unlikely(to_wakeup == prev))
+						deactivate = false;
+					else
+						try_to_wake_up_local(to_wakeup);
+				}
+			}
+		}
+		switch_count = &prev->nvcsw;
+	}
+
+	update_clocks(rq);
+	update_cpu_clock_switch(rq, prev);
+	if (rq->clock - rq->last_tick > HALF_JIFFY_NS)
+		rq->dither = false;
+	else
+		rq->dither = true;
+
+	clear_tsk_need_resched(prev);
+	clear_preempt_need_resched();
+
+	idle = rq->idle;
+	if (idle != prev) {
+		/* Update all the information stored on struct rq */
+		prev->time_slice = rq->rq_time_slice;
+		prev->deadline = rq->rq_deadline;
+		check_deadline(prev);
+		prev->last_ran = rq->clock_task;
+
+		/* Task changed affinity off this CPU */
+		if (likely(!needs_other_cpu(prev, cpu))) {
+			if (!deactivate) {
+				if (!queued_notrunning()) {
+					/*
+					 * We now know prev is the only thing that is
+					 * awaiting CPU so we can bypass rechecking for
+					 * the earliest deadline task and just run it
+					 * again.
+					 */
+					set_rq_task(rq, prev);
+					check_smt_siblings(cpu);
+					grq_unlock_irq();
+					goto rerun_prev_unlocked;
+				} else
+					swap_sticky(rq, cpu, prev);
+			}
+		}
+		return_task(prev, rq, deactivate);
+	}
+
+	if (unlikely(!queued_notrunning())) {
+		/*
+		 * This CPU is now truly idle as opposed to when idle is
+		 * scheduled as a high priority task in its own right.
+		 */
+		next = idle;
+		schedstat_inc(rq, sched_goidle);
+		set_cpuidle_map(cpu);
+	} else {
+		next = earliest_deadline_task(rq, cpu, idle);
+		if (likely(next->prio != PRIO_LIMIT))
+			clear_cpuidle_map(cpu);
+		else
+			set_cpuidle_map(cpu);
+	}
+
+	if (likely(prev != next)) {
+		/*
+		 * Don't reschedule an idle task or deactivated tasks
+		 */
+		if (prev != idle && !deactivate)
+			resched_suitable_idle(prev);
+		/*
+		 * Don't stick tasks when a real time task is going to run as
+		 * they may literally get stuck.
+		 */
+		if (rt_task(next))
+			unstick_task(rq, prev);
+		set_rq_task(rq, next);
+		if (next != idle)
+			check_smt_siblings(cpu);
+		else
+			wake_smt_siblings(cpu);
+		grq.nr_switches++;
+		prev->on_cpu = false;
+		next->on_cpu = true;
+		rq->curr = next;
+		++*switch_count;
+
+		trace_sched_switch(preempt, prev, next);
+		rq = context_switch(rq, prev, next); /* unlocks the grq */
+		cpu = cpu_of(rq);
+		idle = rq->idle;
+	} else {
+		check_smt_siblings(cpu);
+		grq_unlock_irq();
+	}
+
+rerun_prev_unlocked:
+	return;
+}
+
+static inline void sched_submit_work(struct task_struct *tsk)
+{
+	if (!tsk->state || tsk_is_pi_blocked(tsk) ||
+	    preempt_count() ||
+	    signal_pending_state(tsk->state, tsk))
+		return;
+
+	/*
+	 * If we are going to sleep and we have plugged IO queued,
+	 * make sure to submit it to avoid deadlocks.
+	 */
+	if (blk_needs_flush_plug(tsk))
+		blk_schedule_flush_plug(tsk);
+}
+
+asmlinkage __visible void __sched schedule(void)
+{
+	struct task_struct *tsk = current;
+
+	sched_submit_work(tsk);
+	do {
+		preempt_disable();
+		__schedule(false);
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+}
+
+EXPORT_SYMBOL(schedule);
+
+#ifdef CONFIG_CONTEXT_TRACKING
+asmlinkage __visible void __sched schedule_user(void)
+{
+	/*
+	 * If we come here after a random call to set_need_resched(),
+	 * or we have been woken up remotely but the IPI has not yet arrived,
+	 * we haven't yet exited the RCU idle mode. Do it here manually until
+	 * we find a better solution.
+	 *
+	 * NB: There are buggy callers of this function.  Ideally we
+	 * should warn if prev_state != IN_USER, but that will trigger
+	 * too frequently to make sense yet.
+	 */
+	enum ctx_state prev_state = exception_enter();
+	schedule();
+	exception_exit(prev_state);
+}
+#endif
+
+/**
+ * schedule_preempt_disabled - called with preemption disabled
+ *
+ * Returns with preemption disabled. Note: preempt_count must be 1
+ */
+void __sched schedule_preempt_disabled(void)
+{
+	sched_preempt_enable_no_resched();
+	schedule();
+	preempt_disable();
+}
+
+static void __sched notrace preempt_schedule_common(void)
+{
+	do {
+		preempt_disable_notrace();
+		__schedule(true);
+		preempt_enable_no_resched_notrace();
+
+		/*
+		 * Check again in case we missed a preemption opportunity
+		 * between schedule and now.
+		 */
+	} while (need_resched());
+}
+
+#ifdef CONFIG_PREEMPT
+/*
+ * this is the entry point to schedule() from in-kernel preemption
+ * off of preempt_enable. Kernel preemptions off return from interrupt
+ * occur there and call schedule directly.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule(void)
+{
+	/*
+	 * If there is a non-zero preempt_count or interrupts are disabled,
+	 * we do not want to preempt the current task. Just return..
+	 */
+	if (likely(!preemptible()))
+		return;
+
+	preempt_schedule_common();
+}
+NOKPROBE_SYMBOL(preempt_schedule);
+EXPORT_SYMBOL(preempt_schedule);
+
+/**
+ * preempt_schedule_notrace - preempt_schedule called by tracing
+ *
+ * The tracing infrastructure uses preempt_enable_notrace to prevent
+ * recursion and tracing preempt enabling caused by the tracing
+ * infrastructure itself. But as tracing can happen in areas coming
+ * from userspace or just about to enter userspace, a preempt enable
+ * can occur before user_exit() is called. This will cause the scheduler
+ * to be called when the system is still in usermode.
+ *
+ * To prevent this, the preempt_enable_notrace will use this function
+ * instead of preempt_schedule() to exit user context if needed before
+ * calling the scheduler.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
+{
+	enum ctx_state prev_ctx;
+
+	if (likely(!preemptible()))
+		return;
+
+	do {
+		preempt_disable_notrace();
+		/*
+		 * Needs preempt disabled in case user_exit() is traced
+		 * and the tracer calls preempt_enable_notrace() causing
+		 * an infinite recursion.
+		 */
+		prev_ctx = exception_enter();
+		__schedule(true);
+		exception_exit(prev_ctx);
+
+		preempt_enable_no_resched_notrace();
+	} while (need_resched());
+}
+EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
+
+#endif /* CONFIG_PREEMPT */
+
+/*
+ * this is the entry point to schedule() from kernel preemption
+ * off of irq context.
+ * Note, that this is called and return with irqs disabled. This will
+ * protect us against recursive calling from irq.
+ */
+asmlinkage __visible void __sched preempt_schedule_irq(void)
+{
+	enum ctx_state prev_state;
+
+	/* Catch callers which need to be fixed */
+	BUG_ON(preempt_count() || !irqs_disabled());
+
+	prev_state = exception_enter();
+
+	do {
+		preempt_disable();
+		local_irq_enable();
+		__schedule(true);
+		local_irq_disable();
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+
+	exception_exit(prev_state);
+}
+
+int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
+			  void *key)
+{
+	return try_to_wake_up(curr->private, mode, wake_flags);
+}
+EXPORT_SYMBOL(default_wake_function);
+
+#ifdef CONFIG_RT_MUTEXES
+
+/*
+ * rt_mutex_setprio - set the current priority of a task
+ * @p: task
+ * @prio: prio value (kernel-internal form)
+ *
+ * This function changes the 'effective' priority of a task. It does
+ * not touch ->normal_prio like __setscheduler().
+ *
+ * Used by the rt_mutex code to implement priority inheritance
+ * logic. Call site only calls if the priority of the task changed.
+ */
+void rt_mutex_setprio(struct task_struct *p, int prio)
+{
+	unsigned long flags;
+	int queued, oldprio;
+	struct rq *rq;
+
+	BUG_ON(prio < 0 || prio > MAX_PRIO);
+
+	rq = task_grq_lock(p, &flags);
+
+	/*
+	 * Idle task boosting is a nono in general. There is one
+	 * exception, when PREEMPT_RT and NOHZ is active:
+	 *
+	 * The idle task calls get_next_timer_interrupt() and holds
+	 * the timer wheel base->lock on the CPU and another CPU wants
+	 * to access the timer (probably to cancel it). We can safely
+	 * ignore the boosting request, as the idle CPU runs this code
+	 * with interrupts disabled and will complete the lock
+	 * protected section without being interrupted. So there is no
+	 * real need to boost.
+	 */
+	if (unlikely(p == rq->idle)) {
+		WARN_ON(p != rq->curr);
+		WARN_ON(p->pi_blocked_on);
+		goto out_unlock;
+	}
+
+	trace_sched_pi_setprio(p, prio);
+	oldprio = p->prio;
+	queued = task_queued(p);
+	if (queued)
+		dequeue_task(p);
+	p->prio = prio;
+	if (task_running(p) && prio > oldprio)
+		resched_task(p);
+	if (queued) {
+		enqueue_task(p, rq);
+		try_preempt(p, rq);
+	}
+
+out_unlock:
+	task_grq_unlock(&flags);
+}
+
+#endif
+
+/*
+ * Adjust the deadline for when the priority is to change, before it's
+ * changed.
+ */
+static inline void adjust_deadline(struct task_struct *p, int new_prio)
+{
+	p->deadline += static_deadline_diff(new_prio) - task_deadline_diff(p);
+}
+
+void set_user_nice(struct task_struct *p, long nice)
+{
+	int queued, new_static, old_static;
+	unsigned long flags;
+	struct rq *rq;
+
+	if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
+		return;
+	new_static = NICE_TO_PRIO(nice);
+	/*
+	 * We have to be careful, if called from sys_setpriority(),
+	 * the task might be in the middle of scheduling on another CPU.
+	 */
+	rq = time_task_grq_lock(p, &flags);
+	/*
+	 * The RT priorities are set via sched_setscheduler(), but we still
+	 * allow the 'normal' nice value to be set - but as expected
+	 * it wont have any effect on scheduling until the task is
+	 * not SCHED_NORMAL/SCHED_BATCH:
+	 */
+	if (has_rt_policy(p)) {
+		p->static_prio = new_static;
+		goto out_unlock;
+	}
+	queued = task_queued(p);
+	if (queued)
+		dequeue_task(p);
+
+	adjust_deadline(p, new_static);
+	old_static = p->static_prio;
+	p->static_prio = new_static;
+	p->prio = effective_prio(p);
+
+	if (queued) {
+		enqueue_task(p, rq);
+		if (new_static < old_static)
+			try_preempt(p, rq);
+	} else if (task_running(p)) {
+		reset_rq_task(rq, p);
+		if (old_static < new_static)
+			resched_task(p);
+	}
+out_unlock:
+	task_grq_unlock(&flags);
+}
+EXPORT_SYMBOL(set_user_nice);
+
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const struct task_struct *p, const int nice)
+{
+	/* convert nice value [19,-20] to rlimit style value [1,40] */
+	int nice_rlim = nice_to_rlimit(nice);
+
+	return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
+		capable(CAP_SYS_NICE));
+}
+
+#ifdef __ARCH_WANT_SYS_NICE
+
+/*
+ * sys_nice - change the priority of the current process.
+ * @increment: priority increment
+ *
+ * sys_setpriority is a more generic, but much slower function that
+ * does similar things.
+ */
+SYSCALL_DEFINE1(nice, int, increment)
+{
+	long nice, retval;
+
+	/*
+	 * Setpriority might change our priority at the same moment.
+	 * We don't have to worry. Conceptually one call occurs first
+	 * and we have a single winner.
+	 */
+
+	increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
+	nice = task_nice(current) + increment;
+
+	nice = clamp_val(nice, MIN_NICE, MAX_NICE);
+	if (increment < 0 && !can_nice(current, nice))
+		return -EPERM;
+
+	retval = security_task_setnice(current, nice);
+	if (retval)
+		return retval;
+
+	set_user_nice(current, nice);
+	return 0;
+}
+
+#endif
+
+/**
+ * task_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * Return: The priority value as seen by users in /proc.
+ * RT tasks are offset by -100. Normal tasks are centered around 1, value goes
+ * from 0 (SCHED_ISO) up to 82 (nice +19 SCHED_IDLEPRIO).
+ */
+int task_prio(const struct task_struct *p)
+{
+	int delta, prio = p->prio - MAX_RT_PRIO;
+
+	/* rt tasks and iso tasks */
+	if (prio <= 0)
+		goto out;
+
+	/* Convert to ms to avoid overflows */
+	delta = NS_TO_MS(p->deadline - grq.niffies);
+	delta = delta * 40 / ms_longest_deadline_diff();
+	if (delta > 0 && delta <= 80)
+		prio += delta;
+	if (idleprio_task(p))
+		prio += 40;
+out:
+	return prio;
+}
+
+/**
+ * idle_cpu - is a given cpu idle currently?
+ * @cpu: the processor in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int idle_cpu(int cpu)
+{
+	return cpu_curr(cpu) == cpu_rq(cpu)->idle;
+}
+
+/**
+ * idle_task - return the idle task for a given cpu.
+ * @cpu: the processor in question.
+ *
+ * Return: The idle task for the cpu @cpu.
+ */
+struct task_struct *idle_task(int cpu)
+{
+	return cpu_rq(cpu)->idle;
+}
+
+/**
+ * find_process_by_pid - find a process with a matching PID value.
+ * @pid: the pid in question.
+ *
+ * The task of @pid, if found. %NULL otherwise.
+ */
+static inline struct task_struct *find_process_by_pid(pid_t pid)
+{
+	return pid ? find_task_by_vpid(pid) : current;
+}
+
+/* Actually do priority change: must hold grq lock. */
+static void __setscheduler(struct task_struct *p, struct rq *rq, int policy,
+			   int prio, bool keep_boost)
+{
+	int oldrtprio, oldprio;
+
+	p->policy = policy;
+	oldrtprio = p->rt_priority;
+	p->rt_priority = prio;
+	p->normal_prio = normal_prio(p);
+	oldprio = p->prio;
+	/*
+	 * Keep a potential priority boosting if called from
+	 * sched_setscheduler().
+	 */
+	if (keep_boost) {
+		/*
+		 * Take priority boosted tasks into account. If the new
+		 * effective priority is unchanged, we just store the new
+		 * normal parameters and do not touch the scheduler class and
+		 * the runqueue. This will be done when the task deboost
+		 * itself.
+		 */
+		p->prio = rt_mutex_get_effective_prio(p, p->normal_prio);
+	} else
+		p->prio = p->normal_prio;
+	if (task_running(p)) {
+		reset_rq_task(rq, p);
+		/* Resched only if we might now be preempted */
+		if (p->prio > oldprio || p->rt_priority > oldrtprio)
+			resched_task(p);
+	}
+}
+
+/*
+ * check the target process has a UID that matches the current process's
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+	const struct cred *cred = current_cred(), *pcred;
+	bool match;
+
+	rcu_read_lock();
+	pcred = __task_cred(p);
+	match = (uid_eq(cred->euid, pcred->euid) ||
+		 uid_eq(cred->euid, pcred->uid));
+	rcu_read_unlock();
+	return match;
+}
+
+static int
+__sched_setscheduler(struct task_struct *p, int policy,
+		     const struct sched_param *param, bool user, bool pi)
+{
+	struct sched_param zero_param = { .sched_priority = 0 };
+	int queued, retval, oldpolicy = -1;
+	unsigned long flags, rlim_rtprio = 0;
+	int reset_on_fork;
+	struct rq *rq;
+
+	/* may grab non-irq protected spin_locks */
+	BUG_ON(in_interrupt());
+
+	if (is_rt_policy(policy) && !capable(CAP_SYS_NICE)) {
+		unsigned long lflags;
+
+		if (!lock_task_sighand(p, &lflags))
+			return -ESRCH;
+		rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
+		unlock_task_sighand(p, &lflags);
+		if (rlim_rtprio)
+			goto recheck;
+		/*
+		 * If the caller requested an RT policy without having the
+		 * necessary rights, we downgrade the policy to SCHED_ISO.
+		 * We also set the parameter to zero to pass the checks.
+		 */
+		policy = SCHED_ISO;
+		param = &zero_param;
+	}
+recheck:
+	/* double check policy once rq lock held */
+	if (policy < 0) {
+		reset_on_fork = p->sched_reset_on_fork;
+		policy = oldpolicy = p->policy;
+	} else {
+		reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
+		policy &= ~SCHED_RESET_ON_FORK;
+
+		if (!SCHED_RANGE(policy))
+			return -EINVAL;
+	}
+
+	/*
+	 * Valid priorities for SCHED_FIFO and SCHED_RR are
+	 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and
+	 * SCHED_BATCH is 0.
+	 */
+	if (param->sched_priority < 0 ||
+	    (p->mm && param->sched_priority > MAX_USER_RT_PRIO - 1) ||
+	    (!p->mm && param->sched_priority > MAX_RT_PRIO - 1))
+		return -EINVAL;
+	if (is_rt_policy(policy) != (param->sched_priority != 0))
+		return -EINVAL;
+
+	/*
+	 * Allow unprivileged RT tasks to decrease priority:
+	 */
+	if (user && !capable(CAP_SYS_NICE)) {
+		if (is_rt_policy(policy)) {
+			unsigned long rlim_rtprio =
+					task_rlimit(p, RLIMIT_RTPRIO);
+
+			/* can't set/change the rt policy */
+			if (policy != p->policy && !rlim_rtprio)
+				return -EPERM;
+
+			/* can't increase priority */
+			if (param->sched_priority > p->rt_priority &&
+			    param->sched_priority > rlim_rtprio)
+				return -EPERM;
+		} else {
+			switch (p->policy) {
+				/*
+				 * Can only downgrade policies but not back to
+				 * SCHED_NORMAL
+				 */
+				case SCHED_ISO:
+					if (policy == SCHED_ISO)
+						goto out;
+					if (policy == SCHED_NORMAL)
+						return -EPERM;
+					break;
+				case SCHED_BATCH:
+					if (policy == SCHED_BATCH)
+						goto out;
+					if (policy != SCHED_IDLEPRIO)
+						return -EPERM;
+					break;
+				case SCHED_IDLEPRIO:
+					if (policy == SCHED_IDLEPRIO)
+						goto out;
+					return -EPERM;
+				default:
+					break;
+			}
+		}
+
+		/* can't change other user's priorities */
+		if (!check_same_owner(p))
+			return -EPERM;
+
+		/* Normal users shall not reset the sched_reset_on_fork flag */
+		if (p->sched_reset_on_fork && !reset_on_fork)
+			return -EPERM;
+	}
+
+	if (user) {
+		retval = security_task_setscheduler(p);
+		if (retval)
+			return retval;
+	}
+
+	/*
+	 * make sure no PI-waiters arrive (or leave) while we are
+	 * changing the priority of the task:
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	/*
+	 * To be able to change p->policy safely, the grunqueue lock must be
+	 * held.
+	 */
+	rq = __task_grq_lock(p);
+
+	/*
+	 * Changing the policy of the stop threads its a very bad idea
+	 */
+	if (p == rq->stop) {
+		__task_grq_unlock();
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		return -EINVAL;
+	}
+
+	/*
+	 * If not changing anything there's no need to proceed further:
+	 */
+	if (unlikely(policy == p->policy && (!is_rt_policy(policy) ||
+			param->sched_priority == p->rt_priority))) {
+
+		__task_grq_unlock();
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		return 0;
+	}
+
+	/* recheck policy now with rq lock held */
+	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
+		policy = oldpolicy = -1;
+		__task_grq_unlock();
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		goto recheck;
+	}
+	update_clocks(rq);
+	p->sched_reset_on_fork = reset_on_fork;
+
+	queued = task_queued(p);
+	if (queued)
+		dequeue_task(p);
+	__setscheduler(p, rq, policy, param->sched_priority, pi);
+	if (queued) {
+		enqueue_task(p, rq);
+		try_preempt(p, rq);
+	}
+	__task_grq_unlock();
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	if (pi)
+		rt_mutex_adjust_pi(p);
+out:
+	return 0;
+}
+
+/**
+ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ *
+ * NOTE that the task may be already dead.
+ */
+int sched_setscheduler(struct task_struct *p, int policy,
+		       const struct sched_param *param)
+{
+	return __sched_setscheduler(p, policy, param, true, true);
+}
+
+EXPORT_SYMBOL_GPL(sched_setscheduler);
+
+int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
+{
+	const struct sched_param param = { .sched_priority = attr->sched_priority };
+	int policy = attr->sched_policy;
+
+	return __sched_setscheduler(p, policy, &param, true, true);
+}
+EXPORT_SYMBOL_GPL(sched_setattr);
+
+/**
+ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Just like sched_setscheduler, only don't bother checking if the
+ * current context has permission.  For example, this is needed in
+ * stop_machine(): we create temporary high priority worker threads,
+ * but our caller might not have that capability.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+int sched_setscheduler_nocheck(struct task_struct *p, int policy,
+			       const struct sched_param *param)
+{
+	return __sched_setscheduler(p, policy, param, false, true);
+}
+EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
+
+static int
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+	struct sched_param lparam;
+	struct task_struct *p;
+	int retval;
+
+	if (!param || pid < 0)
+		return -EINVAL;
+	if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+		return -EFAULT;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (p != NULL)
+		retval = sched_setscheduler(p, policy, &lparam);
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/*
+ * Mimics kernel/events/core.c perf_copy_attr().
+ */
+static int sched_copy_attr(struct sched_attr __user *uattr,
+			   struct sched_attr *attr)
+{
+	u32 size;
+	int ret;
+
+	if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0))
+		return -EFAULT;
+
+	/*
+	 * zero the full structure, so that a short copy will be nice.
+	 */
+	memset(attr, 0, sizeof(*attr));
+
+	ret = get_user(size, &uattr->size);
+	if (ret)
+		return ret;
+
+	if (size > PAGE_SIZE)	/* silly large */
+		goto err_size;
+
+	if (!size)		/* abi compat */
+		size = SCHED_ATTR_SIZE_VER0;
+
+	if (size < SCHED_ATTR_SIZE_VER0)
+		goto err_size;
+
+	/*
+	 * If we're handed a bigger struct than we know of,
+	 * ensure all the unknown bits are 0 - i.e. new
+	 * user-space does not rely on any kernel feature
+	 * extensions we dont know about yet.
+	 */
+	if (size > sizeof(*attr)) {
+		unsigned char __user *addr;
+		unsigned char __user *end;
+		unsigned char val;
+
+		addr = (void __user *)uattr + sizeof(*attr);
+		end  = (void __user *)uattr + size;
+
+		for (; addr < end; addr++) {
+			ret = get_user(val, addr);
+			if (ret)
+				return ret;
+			if (val)
+				goto err_size;
+		}
+		size = sizeof(*attr);
+	}
+
+	ret = copy_from_user(attr, uattr, size);
+	if (ret)
+		return -EFAULT;
+
+	/*
+	 * XXX: do we want to be lenient like existing syscalls; or do we want
+	 * to be strict and return an error on out-of-bounds values?
+	 */
+	attr->sched_nice = clamp(attr->sched_nice, -20, 19);
+
+	/* sched/core.c uses zero here but we already know ret is zero */
+	return 0;
+
+err_size:
+	put_user(sizeof(*attr), &uattr->size);
+	return -E2BIG;
+}
+
+/**
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
+ * @pid: the pid in question.
+ * @policy: new policy.
+ *
+ * Return: 0 on success. An error code otherwise.
+ * @param: structure containing the new RT priority.
+ */
+asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
+				       struct sched_param __user *param)
+{
+	/* negative values for policy are not valid */
+	if (policy < 0)
+		return -EINVAL;
+
+	return do_sched_setscheduler(pid, policy, param);
+}
+
+/*
+ * sched_setparam() passes in -1 for its policy, to let the functions
+ * it calls know not to change it.
+ */
+#define SETPARAM_POLICY	-1
+
+/**
+ * sys_sched_setparam - set/change the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
+{
+	return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
+}
+
+/**
+ * sys_sched_setattr - same as above, but with extended sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ */
+SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
+			       unsigned int, flags)
+{
+	struct sched_attr attr;
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || flags)
+		return -EINVAL;
+
+	retval = sched_copy_attr(uattr, &attr);
+	if (retval)
+		return retval;
+
+	if ((int)attr.sched_policy < 0)
+		return -EINVAL;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (p != NULL)
+		retval = sched_setattr(p, &attr);
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
+ * @pid: the pid in question.
+ *
+ * Return: On success, the policy of the thread. Otherwise, a negative error
+ * code.
+ */
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
+{
+	struct task_struct *p;
+	int retval = -EINVAL;
+
+	if (pid < 0)
+		goto out_nounlock;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (p) {
+		retval = security_task_getscheduler(p);
+		if (!retval)
+			retval = p->policy;
+	}
+	rcu_read_unlock();
+
+out_nounlock:
+	return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the RT priority.
+ *
+ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
+ * code.
+ */
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
+{
+	struct sched_param lp = { .sched_priority = 0 };
+	struct task_struct *p;
+	int retval = -EINVAL;
+
+	if (!param || pid < 0)
+		goto out_nounlock;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	if (has_rt_policy(p))
+		lp.sched_priority = p->rt_priority;
+	rcu_read_unlock();
+
+	/*
+	 * This one might sleep, we cannot do it with a spinlock held ...
+	 */
+	retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
+
+out_nounlock:
+	return retval;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+static int sched_read_attr(struct sched_attr __user *uattr,
+			   struct sched_attr *attr,
+			   unsigned int usize)
+{
+	int ret;
+
+	if (!access_ok(VERIFY_WRITE, uattr, usize))
+		return -EFAULT;
+
+	/*
+	 * If we're handed a smaller struct than we know of,
+	 * ensure all the unknown bits are 0 - i.e. old
+	 * user-space does not get uncomplete information.
+	 */
+	if (usize < sizeof(*attr)) {
+		unsigned char *addr;
+		unsigned char *end;
+
+		addr = (void *)attr + usize;
+		end  = (void *)attr + sizeof(*attr);
+
+		for (; addr < end; addr++) {
+			if (*addr)
+				return -EFBIG;
+		}
+
+		attr->size = usize;
+	}
+
+	ret = copy_to_user(uattr, attr, attr->size);
+	if (ret)
+		return -EFAULT;
+
+	/* sched/core.c uses zero here but we already know ret is zero */
+	return ret;
+}
+
+/**
+ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ * @size: sizeof(attr) for fwd/bwd comp.
+ * @flags: for future extension.
+ */
+SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
+		unsigned int, size, unsigned int, flags)
+{
+	struct sched_attr attr = {
+		.size = sizeof(struct sched_attr),
+	};
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || size > PAGE_SIZE ||
+	    size < SCHED_ATTR_SIZE_VER0 || flags)
+		return -EINVAL;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	attr.sched_policy = p->policy;
+	if (rt_task(p))
+		attr.sched_priority = p->rt_priority;
+	else
+		attr.sched_nice = task_nice(p);
+
+	rcu_read_unlock();
+
+	retval = sched_read_attr(uattr, &attr, size);
+	return retval;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
+	cpumask_var_t cpus_allowed, new_mask;
+	struct task_struct *p;
+	int retval;
+
+	get_online_cpus();
+	rcu_read_lock();
+
+	p = find_process_by_pid(pid);
+	if (!p) {
+		rcu_read_unlock();
+		put_online_cpus();
+		return -ESRCH;
+	}
+
+	/* Prevent p going away */
+	get_task_struct(p);
+	rcu_read_unlock();
+
+	if (p->flags & PF_NO_SETAFFINITY) {
+		retval = -EINVAL;
+		goto out_put_task;
+	}
+	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_put_task;
+	}
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_free_cpus_allowed;
+	}
+	retval = -EPERM;
+	if (!check_same_owner(p)) {
+		rcu_read_lock();
+		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+			rcu_read_unlock();
+			goto out_unlock;
+		}
+		rcu_read_unlock();
+	}
+
+	retval = security_task_setscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	cpumask_and(new_mask, in_mask, cpus_allowed);
+again:
+	retval = __set_cpus_allowed_ptr(p, new_mask, true);
+
+	if (!retval) {
+		cpuset_cpus_allowed(p, cpus_allowed);
+		if (!cpumask_subset(new_mask, cpus_allowed)) {
+			/*
+			 * We must have raced with a concurrent cpuset
+			 * update. Just reset the cpus_allowed to the
+			 * cpuset's cpus_allowed
+			 */
+			cpumask_copy(new_mask, cpus_allowed);
+			goto again;
+		}
+	}
+out_unlock:
+	free_cpumask_var(new_mask);
+out_free_cpus_allowed:
+	free_cpumask_var(cpus_allowed);
+out_put_task:
+	put_task_struct(p);
+	put_online_cpus();
+	return retval;
+}
+
+static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
+			     cpumask_t *new_mask)
+{
+	if (len < sizeof(cpumask_t)) {
+		memset(new_mask, 0, sizeof(cpumask_t));
+	} else if (len > sizeof(cpumask_t)) {
+		len = sizeof(cpumask_t);
+	}
+	return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
+}
+
+
+/**
+ * sys_sched_setaffinity - set the cpu affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to the new cpu mask
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	cpumask_var_t new_mask;
+	int retval;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
+	if (retval == 0)
+		retval = sched_setaffinity(pid, new_mask);
+	free_cpumask_var(new_mask);
+	return retval;
+}
+
+long sched_getaffinity(pid_t pid, cpumask_t *mask)
+{
+	struct task_struct *p;
+	unsigned long flags;
+	int retval;
+
+	get_online_cpus();
+	rcu_read_lock();
+
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	grq_lock_irqsave(&flags);
+	cpumask_and(mask, tsk_cpus_allowed(p), cpu_active_mask);
+	grq_unlock_irqrestore(&flags);
+
+out_unlock:
+	rcu_read_unlock();
+	put_online_cpus();
+
+	return retval;
+}
+
+/**
+ * sys_sched_getaffinity - get the cpu affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to hold the current cpu mask
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	int ret;
+	cpumask_var_t mask;
+
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
+		return -EINVAL;
+	if (len & (sizeof(unsigned long)-1))
+		return -EINVAL;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = sched_getaffinity(pid, mask);
+	if (ret == 0) {
+		size_t retlen = min_t(size_t, len, cpumask_size());
+
+		if (copy_to_user(user_mask_ptr, mask, retlen))
+			ret = -EFAULT;
+		else
+			ret = retlen;
+	}
+	free_cpumask_var(mask);
+
+	return ret;
+}
+
+/**
+ * sys_sched_yield - yield the current processor to other threads.
+ *
+ * This function yields the current CPU to other tasks. It does this by
+ * scheduling away the current task. If it still has the earliest deadline
+ * it will be scheduled again as the next task.
+ *
+ * Return: 0.
+ */
+SYSCALL_DEFINE0(sched_yield)
+{
+	struct task_struct *p;
+
+	p = current;
+	grq_lock_irq();
+	schedstat_inc(task_rq(p), yld_count);
+	requeue_task(p);
+
+	/*
+	 * Since we are going to call schedule() anyway, there's
+	 * no need to preempt or enable interrupts:
+	 */
+	__release(grq.lock);
+	spin_release(&grq.lock.dep_map, 1, _THIS_IP_);
+	do_raw_spin_unlock(&grq.lock);
+	sched_preempt_enable_no_resched();
+
+	schedule();
+
+	return 0;
+}
+
+int __sched _cond_resched(void)
+{
+	if (should_resched(0)) {
+		preempt_schedule_common();
+		return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(_cond_resched);
+
+/*
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * call schedule, and on return reacquire the lock.
+ *
+ * This works OK both with and without CONFIG_PREEMPT.  We do strange low-level
+ * operations here to prevent schedule() from being called twice (once via
+ * spin_unlock(), once by hand).
+ */
+int __cond_resched_lock(spinlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held(lock);
+
+	if (spin_needbreak(lock) || resched) {
+		spin_unlock(lock);
+		if (resched)
+			preempt_schedule_common();
+		else
+			cpu_relax();
+		ret = 1;
+		spin_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_lock);
+
+int __sched __cond_resched_softirq(void)
+{
+	BUG_ON(!in_softirq());
+
+	if (should_resched(SOFTIRQ_DISABLE_OFFSET)) {
+		local_bh_enable();
+		preempt_schedule_common();
+		local_bh_disable();
+		return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(__cond_resched_softirq);
+
+/**
+ * yield - yield the current processor to other threads.
+ *
+ * Do not ever use this function, there's a 99% chance you're doing it wrong.
+ *
+ * The scheduler is at all times free to pick the calling task as the most
+ * eligible task to run, if removing the yield() call from your code breaks
+ * it, its already broken.
+ *
+ * Typical broken usage is:
+ *
+ * while (!event)
+ * 	yield();
+ *
+ * where one assumes that yield() will let 'the other' process run that will
+ * make event true. If the current task is a SCHED_FIFO task that will never
+ * happen. Never use yield() as a progress guarantee!!
+ *
+ * If you want to use yield() to wait for something, use wait_event().
+ * If you want to use yield() to be 'nice' for others, use cond_resched().
+ * If you still want to use yield(), do not!
+ */
+void __sched yield(void)
+{
+	set_current_state(TASK_RUNNING);
+	sys_sched_yield();
+}
+EXPORT_SYMBOL(yield);
+
+/**
+ * yield_to - yield the current processor to another thread in
+ * your thread group, or accelerate that thread toward the
+ * processor it's on.
+ * @p: target task
+ * @preempt: whether task preemption is allowed or not
+ *
+ * It's the caller's job to ensure that the target task struct
+ * can't go away on us before we can do any checks.
+ *
+ * Return:
+ *	true (>0) if we indeed boosted the target task.
+ *	false (0) if we failed to boost the target.
+ *	-ESRCH if there's no task to yield to.
+ */
+int __sched yield_to(struct task_struct *p, bool preempt)
+{
+	struct rq *rq, *p_rq;
+	unsigned long flags;
+	int yielded = 0;
+
+	rq = this_rq();
+	grq_lock_irqsave(&flags);
+	if (task_running(p) || p->state) {
+		yielded = -ESRCH;
+		goto out_unlock;
+	}
+
+	p_rq = task_rq(p);
+	yielded = 1;
+	if (p->deadline > rq->rq_deadline)
+		p->deadline = rq->rq_deadline;
+	p->time_slice += rq->rq_time_slice;
+	rq->rq_time_slice = 0;
+	if (p->time_slice > timeslice())
+		p->time_slice = timeslice();
+	if (preempt && rq != p_rq)
+		resched_curr(p_rq);
+out_unlock:
+	grq_unlock_irqrestore(&flags);
+
+	if (yielded > 0)
+		schedule();
+	return yielded;
+}
+EXPORT_SYMBOL_GPL(yield_to);
+
+/*
+ * This task is about to go to sleep on IO.  Increment rq->nr_iowait so
+ * that process accounting knows that this is a task in IO wait state.
+ *
+ * But don't do that if it is a deliberate, throttling IO wait (this task
+ * has set its backing_dev_info: the queue against which it should throttle)
+ */
+
+long __sched io_schedule_timeout(long timeout)
+{
+	int old_iowait = current->in_iowait;
+	struct rq *rq;
+	long ret;
+
+	current->in_iowait = 1;
+	blk_schedule_flush_plug(current);
+
+	delayacct_blkio_start();
+	rq = raw_rq();
+	atomic_inc(&rq->nr_iowait);
+	ret = schedule_timeout(timeout);
+	current->in_iowait = old_iowait;
+	atomic_dec(&rq->nr_iowait);
+	delayacct_blkio_end();
+
+	return ret;
+}
+EXPORT_SYMBOL(io_schedule_timeout);
+
+/**
+ * sys_sched_get_priority_max - return maximum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the maximum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = MAX_USER_RT_PRIO-1;
+		break;
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_ISO:
+	case SCHED_IDLEPRIO:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+/**
+ * sys_sched_get_priority_min - return minimum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the minimum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = 1;
+		break;
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_ISO:
+	case SCHED_IDLEPRIO:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+/**
+ * sys_sched_rr_get_interval - return the default timeslice of a process.
+ * @pid: pid of the process.
+ * @interval: userspace pointer to the timeslice value.
+ *
+ *
+ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
+ * an error code.
+ */
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
+		struct timespec __user *, interval)
+{
+	struct task_struct *p;
+	unsigned int time_slice;
+	unsigned long flags;
+	int retval;
+	struct timespec t;
+
+	if (pid < 0)
+		return -EINVAL;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	grq_lock_irqsave(&flags);
+	time_slice = p->policy == SCHED_FIFO ? 0 : MS_TO_NS(task_timeslice(p));
+	grq_unlock_irqrestore(&flags);
+
+	rcu_read_unlock();
+	t = ns_to_timespec(time_slice);
+	retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
+	return retval;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
+
+void sched_show_task(struct task_struct *p)
+{
+	unsigned long free = 0;
+	int ppid;
+	unsigned long state = p->state;
+
+	if (state)
+		state = __ffs(state) + 1;
+	printk(KERN_INFO "%-15.15s %c", p->comm,
+		state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
+#if BITS_PER_LONG == 32
+	if (state == TASK_RUNNING)
+		printk(KERN_CONT " running  ");
+	else
+		printk(KERN_CONT " %08lx ", thread_saved_pc(p));
+#else
+	if (state == TASK_RUNNING)
+		printk(KERN_CONT "  running task    ");
+	else
+		printk(KERN_CONT " %016lx ", thread_saved_pc(p));
+#endif
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	free = stack_not_used(p);
+#endif
+	ppid = 0;
+	rcu_read_lock();
+	if (pid_alive(p))
+		ppid = task_pid_nr(rcu_dereference(p->real_parent));
+	rcu_read_unlock();
+	printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
+		task_pid_nr(p), ppid,
+		(unsigned long)task_thread_info(p)->flags);
+
+	print_worker_info(KERN_INFO, p);
+	show_stack(p, NULL);
+}
+
+void show_state_filter(unsigned long state_filter)
+{
+	struct task_struct *g, *p;
+
+#if BITS_PER_LONG == 32
+	printk(KERN_INFO
+		"  task                PC stack   pid father\n");
+#else
+	printk(KERN_INFO
+		"  task                        PC stack   pid father\n");
+#endif
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		/*
+		 * reset the NMI-timeout, listing all files on a slow
+		 * console might take a lot of time:
+		 */
+		touch_nmi_watchdog();
+		if (!state_filter || (p->state & state_filter))
+			sched_show_task(p);
+	}
+
+	touch_all_softlockup_watchdogs();
+
+	rcu_read_unlock();
+	/*
+	 * Only show locks if all tasks are dumped:
+	 */
+	if (!state_filter)
+		debug_show_all_locks();
+}
+
+void dump_cpu_task(int cpu)
+{
+	pr_info("Task dump for CPU %d:\n", cpu);
+	sched_show_task(cpu_curr(cpu));
+}
+
+#ifdef CONFIG_SMP
+void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
+{
+	cpumask_copy(&p->cpus_allowed, new_mask);
+	p->nr_cpus_allowed = cpumask_weight(new_mask);
+}
+
+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+{
+	cpumask_copy(tsk_cpus_allowed(p), new_mask);
+}
+#endif
+
+/**
+ * init_idle - set up an idle thread for a given CPU
+ * @idle: task in question
+ * @cpu: cpu the idle task belongs to
+ *
+ * NOTE: this function does not set the idle thread's NEED_RESCHED
+ * flag, to make booting more robust.
+ */
+void init_idle(struct task_struct *idle, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&idle->pi_lock, flags);
+	time_lock_grq(rq);
+	idle->last_ran = rq->clock_task;
+	idle->state = TASK_RUNNING;
+	/* Setting prio to illegal value shouldn't matter when never queued */
+	idle->prio = PRIO_LIMIT;
+
+	kasan_unpoison_task_stack(idle);
+
+#ifdef CONFIG_SMP
+	/*
+	 * It's possible that init_idle() gets called multiple times on a task,
+	 * in that case do_set_cpus_allowed() will not do the right thing.
+	 *
+	 * And since this is boot we can forgo the serialisation.
+	 */
+	set_cpus_allowed_common(idle, cpumask_of(cpu));
+#ifdef CONFIG_SMT_NICE
+	idle->smt_bias = 0;
+#endif
+#endif
+	set_rq_task(rq, idle);
+
+	/* Silence PROVE_RCU */
+	rcu_read_lock();
+	set_task_cpu(idle, cpu);
+	rcu_read_unlock();
+
+	rq->curr = rq->idle = idle;
+	idle->on_cpu = 1;
+	grq_unlock();
+	raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
+
+	/* Set the preempt count _outside_ the spinlocks! */
+	init_idle_preempt_count(idle, cpu);
+
+	ftrace_graph_init_idle_task(idle, cpu);
+#ifdef CONFIG_SMP
+	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
+#endif
+}
+
+int cpuset_cpumask_can_shrink(const struct cpumask __maybe_unused *cur,
+			      const struct cpumask __maybe_unused *trial)
+{
+	return 1;
+}
+
+int task_can_attach(struct task_struct *p,
+		    const struct cpumask *cs_cpus_allowed)
+{
+	int ret = 0;
+
+	/*
+	 * Kthreads which disallow setaffinity shouldn't be moved
+	 * to a new cpuset; we don't want to change their cpu
+	 * affinity and isolating such threads by their set of
+	 * allowed nodes is unnecessary.  Thus, cpusets are not
+	 * applicable for such threads.  This prevents checking for
+	 * success of set_cpus_allowed_ptr() on all attached tasks
+	 * before cpus_allowed may be changed.
+	 */
+	if (p->flags & PF_NO_SETAFFINITY)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+void wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	struct wake_q_node *node = &task->wake_q;
+
+	/*
+	 * Atomically grab the task, if ->wake_q is !nil already it means
+	 * its already queued (either by us or someone else) and will get the
+	 * wakeup due to that.
+	 *
+	 * This cmpxchg() implies a full barrier, which pairs with the write
+	 * barrier implied by the wakeup in wake_up_list().
+	 */
+	if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL))
+		return;
+
+	get_task_struct(task);
+
+	/*
+	 * The head is context local, there can be no concurrency.
+	 */
+	*head->lastp = node;
+	head->lastp = &node->next;
+}
+
+void wake_up_q(struct wake_q_head *head)
+{
+	struct wake_q_node *node = head->first;
+
+	while (node != WAKE_Q_TAIL) {
+		struct task_struct *task;
+
+		task = container_of(node, struct task_struct, wake_q);
+		BUG_ON(!task);
+		/* task can safely be re-inserted now */
+		node = node->next;
+		task->wake_q.next = NULL;
+
+		/*
+		 * wake_up_process() implies a wmb() to pair with the queueing
+		 * in wake_q_add() so as not to miss wakeups.
+		 */
+		wake_up_process(task);
+		put_task_struct(task);
+	}
+}
+
+void resched_cpu(int cpu)
+{
+	unsigned long flags;
+
+	grq_lock_irqsave(&flags);
+	resched_task(cpu_curr(cpu));
+	grq_unlock_irqrestore(&flags);
+}
+
+#ifdef CONFIG_SMP
+#ifdef CONFIG_NO_HZ_COMMON
+void nohz_balance_enter_idle(int cpu)
+{
+}
+
+void select_nohz_load_balancer(int stop_tick)
+{
+}
+
+void set_cpu_sd_state_idle(void) {}
+#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+/**
+ * lowest_flag_domain - Return lowest sched_domain containing flag.
+ * @cpu:	The cpu whose lowest level of sched domain is to
+ *		be returned.
+ * @flag:	The flag to check for the lowest sched_domain
+ *		for the given cpu.
+ *
+ * Returns the lowest sched_domain of a cpu which contains the given flag.
+ */
+static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
+{
+	struct sched_domain *sd;
+
+	for_each_domain(cpu, sd)
+		if (sd && (sd->flags & flag))
+			break;
+
+	return sd;
+}
+
+/**
+ * for_each_flag_domain - Iterates over sched_domains containing the flag.
+ * @cpu:	The cpu whose domains we're iterating over.
+ * @sd:		variable holding the value of the power_savings_sd
+ *		for cpu.
+ * @flag:	The flag to filter the sched_domains to be iterated.
+ *
+ * Iterates over all the scheduler domains for a given cpu that has the 'flag'
+ * set, starting from the lowest sched_domain to the highest.
+ */
+#define for_each_flag_domain(cpu, sd, flag) \
+	for (sd = lowest_flag_domain(cpu, flag); \
+		(sd && (sd->flags & flag)); sd = sd->parent)
+
+#endif /*  (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
+
+/*
+ * In the semi idle case, use the nearest busy cpu for migrating timers
+ * from an idle cpu.  This is good for power-savings.
+ *
+ * We don't do similar optimization for completely idle system, as
+ * selecting an idle cpu will add more delays to the timers than intended
+ * (as that cpu's timer base may not be uptodate wrt jiffies etc).
+ */
+int get_nohz_timer_target(void)
+{
+	int i, cpu = smp_processor_id();
+	struct sched_domain *sd;
+
+	if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu))
+		return cpu;
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd) {
+		for_each_cpu(i, sched_domain_span(sd)) {
+			if (!idle_cpu(i) && is_housekeeping_cpu(cpu)) {
+				cpu = i;
+				goto unlock;
+			}
+		}
+	}
+
+	if (!is_housekeeping_cpu(cpu))
+		cpu = housekeeping_any_cpu();
+unlock:
+	rcu_read_unlock();
+	return cpu;
+}
+
+/*
+ * When add_timer_on() enqueues a timer into the timer wheel of an
+ * idle CPU then this timer might expire before the next timer event
+ * which is scheduled to wake up that CPU. In case of a completely
+ * idle system the next event might even be infinite time into the
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
+ * leaves the inner idle loop so the newly added timer is taken into
+ * account when the CPU goes back to idle and evaluates the timer
+ * wheel for the next timer event.
+ */
+void wake_up_idle_cpu(int cpu)
+{
+	if (cpu == smp_processor_id())
+		return;
+
+	set_tsk_need_resched(cpu_rq(cpu)->idle);
+	smp_send_reschedule(cpu);
+}
+
+void wake_up_nohz_cpu(int cpu)
+{
+	wake_up_idle_cpu(cpu);
+}
+#endif /* CONFIG_NO_HZ_COMMON */
+
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  const struct cpumask *new_mask, bool check)
+{
+	bool running_wrong = false;
+	bool queued = false;
+	unsigned long flags;
+	struct rq *rq;
+	int ret = 0;
+
+	rq = task_grq_lock(p, &flags);
+
+	/*
+	 * Must re-check here, to close a race against __kthread_bind(),
+	 * sched_setaffinity() is not guaranteed to observe the flag.
+	 */
+	if (check && (p->flags & PF_NO_SETAFFINITY)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (cpumask_equal(tsk_cpus_allowed(p), new_mask))
+		goto out;
+
+	if (!cpumask_intersects(new_mask, cpu_active_mask)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	queued = task_queued(p);
+
+	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))
+		goto out;
+
+	if (task_running(p)) {
+		/* Task is running on the wrong cpu now, reschedule it. */
+		if (rq == this_rq()) {
+			set_tsk_need_resched(p);
+			running_wrong = true;
+		} else
+			resched_task(p);
+	} else
+		set_task_cpu(p, cpumask_any_and(cpu_active_mask, new_mask));
+
+out:
+	if (queued)
+		try_preempt(p, rq);
+	task_grq_unlock(&flags);
+
+	if (running_wrong)
+		preempt_schedule_common();
+
+	return ret;
+}
+
+int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
+{
+	return __set_cpus_allowed_ptr(p, new_mask, false);
+}
+EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+
+#ifdef CONFIG_HOTPLUG_CPU
+/* Run through task list and find tasks affined to the dead cpu, then remove
+ * that cpu from the list, enable cpu0 and set the zerobound flag. */
+static void bind_zero(int src_cpu)
+{
+	struct task_struct *p, *t;
+	int bound = 0;
+
+	if (src_cpu == 0)
+		return;
+
+	do_each_thread(t, p) {
+		if (cpumask_test_cpu(src_cpu, tsk_cpus_allowed(p))) {
+			cpumask_clear_cpu(src_cpu, tsk_cpus_allowed(p));
+			cpumask_set_cpu(0, tsk_cpus_allowed(p));
+			p->zerobound = true;
+			bound++;
+		}
+		clear_sticky(p);
+	} while_each_thread(t, p);
+
+	if (bound) {
+		printk(KERN_INFO "Removed affinity for %d processes to cpu %d\n",
+		       bound, src_cpu);
+	}
+}
+
+/* Find processes with the zerobound flag and reenable their affinity for the
+ * CPU coming alive. */
+static void unbind_zero(int src_cpu)
+{
+	int unbound = 0, zerobound = 0;
+	struct task_struct *p, *t;
+
+	if (src_cpu == 0)
+		return;
+
+	do_each_thread(t, p) {
+		if (!p->mm)
+			p->zerobound = false;
+		if (p->zerobound) {
+			unbound++;
+			cpumask_set_cpu(src_cpu, tsk_cpus_allowed(p));
+			/* Once every CPU affinity has been re-enabled, remove
+			 * the zerobound flag */
+			if (cpumask_subset(cpu_possible_mask, tsk_cpus_allowed(p))) {
+				p->zerobound = false;
+				zerobound++;
+			}
+		}
+	} while_each_thread(t, p);
+
+	if (unbound) {
+		printk(KERN_INFO "Added affinity for %d processes to cpu %d\n",
+		       unbound, src_cpu);
+	}
+	if (zerobound) {
+		printk(KERN_INFO "Released forced binding to cpu0 for %d processes\n",
+		       zerobound);
+	}
+}
+
+/*
+ * Ensures that the idle task is using init_mm right before its cpu goes
+ * offline.
+ */
+void idle_task_exit(void)
+{
+	struct mm_struct *mm = current->active_mm;
+
+	BUG_ON(cpu_online(smp_processor_id()));
+
+	if (mm != &init_mm) {
+		switch_mm(mm, &init_mm, current);
+		finish_arch_post_lock_switch();
+	}
+	mmdrop(mm);
+}
+#else /* CONFIG_HOTPLUG_CPU */
+static void unbind_zero(int src_cpu) {}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+void sched_set_stop_task(int cpu, struct task_struct *stop)
+{
+	struct sched_param stop_param = { .sched_priority = STOP_PRIO };
+	struct sched_param start_param = { .sched_priority = 0 };
+	struct task_struct *old_stop = cpu_rq(cpu)->stop;
+
+	if (stop) {
+		/*
+		 * Make it appear like a SCHED_FIFO task, its something
+		 * userspace knows about and won't get confused about.
+		 *
+		 * Also, it will make PI more or less work without too
+		 * much confusion -- but then, stop work should not
+		 * rely on PI working anyway.
+		 */
+		sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param);
+	}
+
+	cpu_rq(cpu)->stop = stop;
+
+	if (old_stop) {
+		/*
+		 * Reset it back to a normal scheduling policy so that
+		 * it can die in pieces.
+		 */
+		sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param);
+	}
+}
+
+
+#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
+
+static struct ctl_table sd_ctl_dir[] = {
+	{
+		.procname	= "sched_domain",
+		.mode		= 0555,
+	},
+	{}
+};
+
+static struct ctl_table sd_ctl_root[] = {
+	{
+		.procname	= "kernel",
+		.mode		= 0555,
+		.child		= sd_ctl_dir,
+	},
+	{}
+};
+
+static struct ctl_table *sd_alloc_ctl_entry(int n)
+{
+	struct ctl_table *entry =
+		kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
+
+	return entry;
+}
+
+static void sd_free_ctl_entry(struct ctl_table **tablep)
+{
+	struct ctl_table *entry;
+
+	/*
+	 * In the intermediate directories, both the child directory and
+	 * procname are dynamically allocated and could fail but the mode
+	 * will always be set. In the lowest directory the names are
+	 * static strings and all have proc handlers.
+	 */
+	for (entry = *tablep; entry->mode; entry++) {
+		if (entry->child)
+			sd_free_ctl_entry(&entry->child);
+		if (entry->proc_handler == NULL)
+			kfree(entry->procname);
+	}
+
+	kfree(*tablep);
+	*tablep = NULL;
+}
+
+static void
+set_table_entry(struct ctl_table *entry,
+		const char *procname, void *data, int maxlen,
+		mode_t mode, proc_handler *proc_handler)
+{
+	entry->procname = procname;
+	entry->data = data;
+	entry->maxlen = maxlen;
+	entry->mode = mode;
+	entry->proc_handler = proc_handler;
+}
+
+static struct ctl_table *
+sd_alloc_ctl_domain_table(struct sched_domain *sd)
+{
+	struct ctl_table *table = sd_alloc_ctl_entry(14);
+
+	if (table == NULL)
+		return NULL;
+
+	set_table_entry(&table[0], "min_interval", &sd->min_interval,
+		sizeof(long), 0644, proc_doulongvec_minmax);
+	set_table_entry(&table[1], "max_interval", &sd->max_interval,
+		sizeof(long), 0644, proc_doulongvec_minmax);
+	set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[9], "cache_nice_tries",
+		&sd->cache_nice_tries,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[10], "flags", &sd->flags,
+		sizeof(int), 0644, proc_dointvec_minmax);
+	set_table_entry(&table[11], "max_newidle_lb_cost",
+		&sd->max_newidle_lb_cost,
+		sizeof(long), 0644, proc_doulongvec_minmax);
+	set_table_entry(&table[12], "name", sd->name,
+		CORENAME_MAX_SIZE, 0444, proc_dostring);
+	/* &table[13] is terminator */
+
+	return table;
+}
+
+static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu)
+{
+	struct ctl_table *entry, *table;
+	struct sched_domain *sd;
+	int domain_num = 0, i;
+	char buf[32];
+
+	for_each_domain(cpu, sd)
+		domain_num++;
+	entry = table = sd_alloc_ctl_entry(domain_num + 1);
+	if (table == NULL)
+		return NULL;
+
+	i = 0;
+	for_each_domain(cpu, sd) {
+		snprintf(buf, 32, "domain%d", i);
+		entry->procname = kstrdup(buf, GFP_KERNEL);
+		entry->mode = 0555;
+		entry->child = sd_alloc_ctl_domain_table(sd);
+		entry++;
+		i++;
+	}
+	return table;
+}
+
+static struct ctl_table_header *sd_sysctl_header;
+static void register_sched_domain_sysctl(void)
+{
+	int i, cpu_num = num_possible_cpus();
+	struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
+	char buf[32];
+
+	WARN_ON(sd_ctl_dir[0].child);
+	sd_ctl_dir[0].child = entry;
+
+	if (entry == NULL)
+		return;
+
+	for_each_possible_cpu(i) {
+		snprintf(buf, 32, "cpu%d", i);
+		entry->procname = kstrdup(buf, GFP_KERNEL);
+		entry->mode = 0555;
+		entry->child = sd_alloc_ctl_cpu_table(i);
+		entry++;
+	}
+
+	WARN_ON(sd_sysctl_header);
+	sd_sysctl_header = register_sysctl_table(sd_ctl_root);
+}
+
+/* may be called multiple times per register */
+static void unregister_sched_domain_sysctl(void)
+{
+	unregister_sysctl_table(sd_sysctl_header);
+	sd_sysctl_header = NULL;
+	if (sd_ctl_dir[0].child)
+		sd_free_ctl_entry(&sd_ctl_dir[0].child);
+}
+#else /* CONFIG_SCHED_DEBUG && CONFIG_SYSCTL */
+static void register_sched_domain_sysctl(void)
+{
+}
+static void unregister_sched_domain_sysctl(void)
+{
+}
+#endif /* CONFIG_SCHED_DEBUG && CONFIG_SYSCTL */
+
+static void set_rq_online(struct rq *rq)
+{
+	if (!rq->online) {
+		cpumask_set_cpu(cpu_of(rq), rq->rd->online);
+		rq->online = true;
+	}
+}
+
+static void set_rq_offline(struct rq *rq)
+{
+	if (rq->online) {
+		cpumask_clear_cpu(cpu_of(rq), rq->rd->online);
+		rq->online = false;
+	}
+}
+
+/*
+ * migration_call - callback that gets triggered when a CPU is added.
+ */
+static int
+migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+	int cpu = (long)hcpu;
+	unsigned long flags;
+	struct rq *rq = cpu_rq(cpu);
+#ifdef CONFIG_HOTPLUG_CPU
+	struct task_struct *idle = rq->idle;
+#endif
+
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_STARTING:
+		return NOTIFY_OK;
+	case CPU_UP_PREPARE:
+		break;
+
+	case CPU_ONLINE:
+		/* Update our root-domain */
+		grq_lock_irqsave(&flags);
+		if (rq->rd) {
+			BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+
+			set_rq_online(rq);
+		}
+		unbind_zero(cpu);
+		grq.noc = num_online_cpus();
+		grq_unlock_irqrestore(&flags);
+		break;
+
+#ifdef CONFIG_HOTPLUG_CPU
+	case CPU_DEAD:
+		grq_lock_irq();
+		set_rq_task(rq, idle);
+		update_clocks(rq);
+		grq_unlock_irq();
+		break;
+
+	case CPU_DYING:
+		/* Update our root-domain */
+		grq_lock_irqsave(&flags);
+		if (rq->rd) {
+			BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+			set_rq_offline(rq);
+		}
+		bind_zero(cpu);
+		grq.noc = num_online_cpus();
+		grq_unlock_irqrestore(&flags);
+		break;
+#endif
+	}
+	return NOTIFY_OK;
+}
+
+/*
+ * Register at high priority so that task migration (migrate_all_tasks)
+ * happens before everything else.  This has to be lower priority than
+ * the notifier in the perf_counter subsystem, though.
+ */
+static struct notifier_block  migration_notifier = {
+	.notifier_call = migration_call,
+	.priority = CPU_PRI_MIGRATION,
+};
+
+static int sched_cpu_active(struct notifier_block *nfb,
+				      unsigned long action, void *hcpu)
+{
+	int cpu = (long)hcpu;
+
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_STARTING:
+		return NOTIFY_OK;
+	case CPU_ONLINE:
+		/*
+		 * At this point a starting CPU has marked itself as online via
+		 * set_cpu_online(). But it might not yet have marked itself
+		 * as active, which is essential from here on.
+		 */
+		set_cpu_active(cpu, true);
+		stop_machine_unpark(cpu);
+		return NOTIFY_OK;
+
+	case CPU_DOWN_FAILED:
+		set_cpu_active(cpu, true);
+		return NOTIFY_OK;
+	default:
+		return NOTIFY_DONE;
+	}
+}
+
+static int sched_cpu_inactive(struct notifier_block *nfb,
+					unsigned long action, void *hcpu)
+{
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_DOWN_PREPARE:
+		set_cpu_active((long)hcpu, false);
+		return NOTIFY_OK;
+	default:
+		return NOTIFY_DONE;
+	}
+}
+
+int __init migration_init(void)
+{
+	void *cpu = (void *)(long)smp_processor_id();
+	int err;
+
+	/* Initialise migration for the boot CPU */
+	err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+	BUG_ON(err == NOTIFY_BAD);
+	migration_call(&migration_notifier, CPU_ONLINE, cpu);
+	register_cpu_notifier(&migration_notifier);
+
+	/* Register cpu active notifiers */
+	cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
+	cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
+
+	return 0;
+}
+early_initcall(migration_init);
+
+static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
+
+#ifdef CONFIG_SCHED_DEBUG
+
+static __read_mostly int sched_debug_enabled;
+
+static int __init sched_debug_setup(char *str)
+{
+	sched_debug_enabled = 1;
+
+	return 0;
+}
+early_param("sched_debug", sched_debug_setup);
+
+static inline bool sched_debug(void)
+{
+	return sched_debug_enabled;
+}
+
+static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
+				  struct cpumask *groupmask)
+{
+	cpumask_clear(groupmask);
+
+	printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
+
+	if (!(sd->flags & SD_LOAD_BALANCE)) {
+		printk("does not load-balance\n");
+		if (sd->parent)
+			printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
+					" has parent");
+		return -1;
+	}
+
+	printk(KERN_CONT "span %*pbl level %s\n",
+	       cpumask_pr_args(sched_domain_span(sd)), sd->name);
+
+	if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
+		printk(KERN_ERR "ERROR: domain->span does not contain "
+				"CPU%d\n", cpu);
+	}
+
+	printk(KERN_CONT "\n");
+
+	if (!cpumask_equal(sched_domain_span(sd), groupmask))
+		printk(KERN_ERR "ERROR: groups don't span domain->span\n");
+
+	if (sd->parent &&
+	    !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
+		printk(KERN_ERR "ERROR: parent span is not a superset "
+			"of domain->span\n");
+	return 0;
+}
+
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+	int level = 0;
+
+	if (!sched_debug_enabled)
+		return;
+
+	if (!sd) {
+		printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
+		return;
+	}
+
+	printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
+
+	for (;;) {
+		if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
+			break;
+		level++;
+		sd = sd->parent;
+		if (!sd)
+			break;
+	}
+}
+#else /* !CONFIG_SCHED_DEBUG */
+# define sched_domain_debug(sd, cpu) do { } while (0)
+static inline bool sched_debug(void)
+{
+	return false;
+}
+#endif /* CONFIG_SCHED_DEBUG */
+
+static int sd_degenerate(struct sched_domain *sd)
+{
+	if (cpumask_weight(sched_domain_span(sd)) == 1)
+		return 1;
+
+	/* Following flags don't use groups */
+	if (sd->flags & (SD_WAKE_AFFINE))
+		return 0;
+
+	return 1;
+}
+
+static int
+sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
+{
+	unsigned long cflags = sd->flags, pflags = parent->flags;
+
+	if (sd_degenerate(parent))
+		return 1;
+
+	if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
+		return 0;
+
+	if (~cflags & pflags)
+		return 0;
+
+	return 1;
+}
+
+static void free_rootdomain(struct rcu_head *rcu)
+{
+	struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
+
+	cpupri_cleanup(&rd->cpupri);
+	free_cpumask_var(rd->rto_mask);
+	free_cpumask_var(rd->online);
+	free_cpumask_var(rd->span);
+	kfree(rd);
+}
+
+static void rq_attach_root(struct rq *rq, struct root_domain *rd)
+{
+	struct root_domain *old_rd = NULL;
+	unsigned long flags;
+
+	grq_lock_irqsave(&flags);
+
+	if (rq->rd) {
+		old_rd = rq->rd;
+
+		if (cpumask_test_cpu(rq->cpu, old_rd->online))
+			set_rq_offline(rq);
+
+		cpumask_clear_cpu(rq->cpu, old_rd->span);
+
+		/*
+		 * If we dont want to free the old_rd yet then
+		 * set old_rd to NULL to skip the freeing later
+		 * in this function:
+		 */
+		if (!atomic_dec_and_test(&old_rd->refcount))
+			old_rd = NULL;
+	}
+
+	atomic_inc(&rd->refcount);
+	rq->rd = rd;
+
+	cpumask_set_cpu(rq->cpu, rd->span);
+	if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
+		set_rq_online(rq);
+
+	grq_unlock_irqrestore(&flags);
+
+	if (old_rd)
+		call_rcu_sched(&old_rd->rcu, free_rootdomain);
+}
+
+static int init_rootdomain(struct root_domain *rd)
+{
+	memset(rd, 0, sizeof(*rd));
+
+	if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
+		goto out;
+	if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
+		goto free_span;
+	if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
+		goto free_online;
+
+	if (cpupri_init(&rd->cpupri) != 0)
+		goto free_rto_mask;
+	return 0;
+
+free_rto_mask:
+	free_cpumask_var(rd->rto_mask);
+free_online:
+	free_cpumask_var(rd->online);
+free_span:
+	free_cpumask_var(rd->span);
+out:
+	return -ENOMEM;
+}
+
+static void init_defrootdomain(void)
+{
+	init_rootdomain(&def_root_domain);
+
+	atomic_set(&def_root_domain.refcount, 1);
+}
+
+static struct root_domain *alloc_rootdomain(void)
+{
+	struct root_domain *rd;
+
+	rd = kmalloc(sizeof(*rd), GFP_KERNEL);
+	if (!rd)
+		return NULL;
+
+	if (init_rootdomain(rd) != 0) {
+		kfree(rd);
+		return NULL;
+	}
+
+	return rd;
+}
+
+static void free_sched_domain(struct rcu_head *rcu)
+{
+	struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
+
+	kfree(sd);
+}
+
+static void destroy_sched_domain(struct sched_domain *sd, int cpu)
+{
+	call_rcu(&sd->rcu, free_sched_domain);
+}
+
+static void destroy_sched_domains(struct sched_domain *sd, int cpu)
+{
+	for (; sd; sd = sd->parent)
+		destroy_sched_domain(sd, cpu);
+}
+
+/*
+ * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
+ * hold the hotplug lock.
+ */
+static void
+cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	struct sched_domain *tmp;
+
+	/* Remove the sched domains which do not contribute to scheduling. */
+	for (tmp = sd; tmp; ) {
+		struct sched_domain *parent = tmp->parent;
+		if (!parent)
+			break;
+
+		if (sd_parent_degenerate(tmp, parent)) {
+			tmp->parent = parent->parent;
+			if (parent->parent)
+				parent->parent->child = tmp;
+			/*
+			 * Transfer SD_PREFER_SIBLING down in case of a
+			 * degenerate parent; the spans match for this
+			 * so the property transfers.
+			 */
+			if (parent->flags & SD_PREFER_SIBLING)
+				tmp->flags |= SD_PREFER_SIBLING;
+			destroy_sched_domain(parent, cpu);
+		} else
+			tmp = tmp->parent;
+	}
+
+	if (sd && sd_degenerate(sd)) {
+		tmp = sd;
+		sd = sd->parent;
+		destroy_sched_domain(tmp, cpu);
+		if (sd)
+			sd->child = NULL;
+	}
+
+	sched_domain_debug(sd, cpu);
+
+	rq_attach_root(rq, rd);
+	tmp = rq->sd;
+	rcu_assign_pointer(rq->sd, sd);
+	destroy_sched_domains(tmp, cpu);
+}
+
+/* Setup the mask of cpus configured for isolated domains */
+static int __init isolated_cpu_setup(char *str)
+{
+	alloc_bootmem_cpumask_var(&cpu_isolated_map);
+	cpulist_parse(str, cpu_isolated_map);
+	return 1;
+}
+
+__setup("isolcpus=", isolated_cpu_setup);
+
+struct s_data {
+	struct sched_domain ** __percpu sd;
+	struct root_domain	*rd;
+};
+
+enum s_alloc {
+	sa_rootdomain,
+	sa_sd,
+	sa_sd_storage,
+	sa_none,
+};
+
+/*
+ * Initializers for schedule domains
+ * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
+ */
+
+static int default_relax_domain_level = -1;
+int sched_domain_level_max;
+
+static int __init setup_relax_domain_level(char *str)
+{
+	if (kstrtoint(str, 0, &default_relax_domain_level))
+		pr_warn("Unable to set relax_domain_level\n");
+
+	return 1;
+}
+__setup("relax_domain_level=", setup_relax_domain_level);
+
+static void set_domain_attribute(struct sched_domain *sd,
+				 struct sched_domain_attr *attr)
+{
+	int request;
+
+	if (!attr || attr->relax_domain_level < 0) {
+		if (default_relax_domain_level < 0)
+			return;
+		else
+			request = default_relax_domain_level;
+	} else
+		request = attr->relax_domain_level;
+	if (request < sd->level) {
+		/* turn off idle balance on this domain */
+		sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
+	} else {
+		/* turn on idle balance on this domain */
+		sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
+	}
+}
+
+static void __sdt_free(const struct cpumask *cpu_map);
+static int __sdt_alloc(const struct cpumask *cpu_map);
+
+static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
+				 const struct cpumask *cpu_map)
+{
+	switch (what) {
+	case sa_rootdomain:
+		if (!atomic_read(&d->rd->refcount))
+			free_rootdomain(&d->rd->rcu); /* fall through */
+	case sa_sd:
+		free_percpu(d->sd); /* fall through */
+	case sa_sd_storage:
+		__sdt_free(cpu_map); /* fall through */
+	case sa_none:
+		break;
+	}
+}
+
+static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
+						   const struct cpumask *cpu_map)
+{
+	memset(d, 0, sizeof(*d));
+
+	if (__sdt_alloc(cpu_map))
+		return sa_sd_storage;
+	d->sd = alloc_percpu(struct sched_domain *);
+	if (!d->sd)
+		return sa_sd_storage;
+	d->rd = alloc_rootdomain();
+	if (!d->rd)
+		return sa_sd;
+	return sa_rootdomain;
+}
+
+/*
+ * NULL the sd_data elements we've used to build the sched_domain
+ * structure so that the subsequent __free_domain_allocs()
+ * will not free the data we're using.
+ */
+static void claim_allocations(int cpu, struct sched_domain *sd)
+{
+	struct sd_data *sdd = sd->private;
+
+	WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
+	*per_cpu_ptr(sdd->sd, cpu) = NULL;
+}
+
+#ifdef CONFIG_NUMA
+static int sched_domains_numa_levels;
+static int *sched_domains_numa_distance;
+static struct cpumask ***sched_domains_numa_masks;
+static int sched_domains_curr_level;
+#endif
+
+/*
+ * SD_flags allowed in topology descriptions.
+ *
+ * SD_SHARE_CPUCAPACITY      - describes SMT topologies
+ * SD_SHARE_PKG_RESOURCES - describes shared caches
+ * SD_NUMA                - describes NUMA topologies
+ * SD_SHARE_POWERDOMAIN   - describes shared power domain
+ *
+ * Odd one out:
+ * SD_ASYM_PACKING        - describes SMT quirks
+ */
+#define TOPOLOGY_SD_FLAGS		\
+	(SD_SHARE_CPUCAPACITY |		\
+	 SD_SHARE_PKG_RESOURCES |	\
+	 SD_NUMA |			\
+	 SD_ASYM_PACKING |		\
+	 SD_SHARE_POWERDOMAIN)
+
+static struct sched_domain *
+sd_init(struct sched_domain_topology_level *tl, int cpu)
+{
+	struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
+	int sd_weight, sd_flags = 0;
+
+#ifdef CONFIG_NUMA
+	/*
+	 * Ugly hack to pass state to sd_numa_mask()...
+	 */
+	sched_domains_curr_level = tl->numa_level;
+#endif
+
+	sd_weight = cpumask_weight(tl->mask(cpu));
+
+	if (tl->sd_flags)
+		sd_flags = (*tl->sd_flags)();
+	if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
+			"wrong sd_flags in topology description\n"))
+		sd_flags &= ~TOPOLOGY_SD_FLAGS;
+
+	*sd = (struct sched_domain){
+		.min_interval		= sd_weight,
+		.max_interval		= 2*sd_weight,
+		.busy_factor		= 32,
+		.imbalance_pct		= 125,
+
+		.cache_nice_tries	= 0,
+		.busy_idx		= 0,
+		.idle_idx		= 0,
+		.newidle_idx		= 0,
+		.wake_idx		= 0,
+		.forkexec_idx		= 0,
+
+		.flags			= 1*SD_LOAD_BALANCE
+					| 1*SD_BALANCE_NEWIDLE
+					| 1*SD_BALANCE_EXEC
+					| 1*SD_BALANCE_FORK
+					| 0*SD_BALANCE_WAKE
+					| 1*SD_WAKE_AFFINE
+					| 0*SD_SHARE_CPUCAPACITY
+					| 0*SD_SHARE_PKG_RESOURCES
+					| 0*SD_SERIALIZE
+					| 0*SD_PREFER_SIBLING
+					| 0*SD_NUMA
+					| sd_flags
+					,
+
+		.last_balance		= jiffies,
+		.balance_interval	= sd_weight,
+		.smt_gain		= 0,
+		.max_newidle_lb_cost	= 0,
+		.next_decay_max_lb_cost	= jiffies,
+#ifdef CONFIG_SCHED_DEBUG
+		.name			= tl->name,
+#endif
+	};
+
+	/*
+	 * Convert topological properties into behaviour.
+	 */
+
+	if (sd->flags & SD_SHARE_CPUCAPACITY) {
+		sd->flags |= SD_PREFER_SIBLING;
+		sd->imbalance_pct = 110;
+		sd->smt_gain = 1178; /* ~15% */
+
+	} else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+		sd->imbalance_pct = 117;
+		sd->cache_nice_tries = 1;
+		sd->busy_idx = 2;
+
+#ifdef CONFIG_NUMA
+	} else if (sd->flags & SD_NUMA) {
+		sd->cache_nice_tries = 2;
+		sd->busy_idx = 3;
+		sd->idle_idx = 2;
+
+		sd->flags |= SD_SERIALIZE;
+		if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) {
+			sd->flags &= ~(SD_BALANCE_EXEC |
+				       SD_BALANCE_FORK |
+				       SD_WAKE_AFFINE);
+		}
+
+#endif
+	} else {
+		sd->flags |= SD_PREFER_SIBLING;
+		sd->cache_nice_tries = 1;
+		sd->busy_idx = 2;
+		sd->idle_idx = 1;
+	}
+
+	sd->private = &tl->data;
+
+	return sd;
+}
+
+/*
+ * Topology list, bottom-up.
+ */
+static struct sched_domain_topology_level default_topology[] = {
+#ifdef CONFIG_SCHED_SMT
+	{ cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
+#endif
+#ifdef CONFIG_SCHED_MC
+	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
+#endif
+	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
+	{ NULL, },
+};
+
+static struct sched_domain_topology_level *sched_domain_topology =
+	default_topology;
+
+#define for_each_sd_topology(tl)			\
+	for (tl = sched_domain_topology; tl->mask; tl++)
+
+void set_sched_topology(struct sched_domain_topology_level *tl)
+{
+	sched_domain_topology = tl;
+}
+
+#ifdef CONFIG_NUMA
+
+static const struct cpumask *sd_numa_mask(int cpu)
+{
+	return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
+}
+
+static void sched_numa_warn(const char *str)
+{
+	static int done = false;
+	int i,j;
+
+	if (done)
+		return;
+
+	done = true;
+
+	printk(KERN_WARNING "ERROR: %s\n\n", str);
+
+	for (i = 0; i < nr_node_ids; i++) {
+		printk(KERN_WARNING "  ");
+		for (j = 0; j < nr_node_ids; j++)
+			printk(KERN_CONT "%02d ", node_distance(i,j));
+		printk(KERN_CONT "\n");
+	}
+	printk(KERN_WARNING "\n");
+}
+
+static bool find_numa_distance(int distance)
+{
+	int i;
+
+	if (distance == node_distance(0, 0))
+		return true;
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		if (sched_domains_numa_distance[i] == distance)
+			return true;
+	}
+
+	return false;
+}
+
+static void sched_init_numa(void)
+{
+	int next_distance, curr_distance = node_distance(0, 0);
+	struct sched_domain_topology_level *tl;
+	int level = 0;
+	int i, j, k;
+
+	sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
+	if (!sched_domains_numa_distance)
+		return;
+
+	/*
+	 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
+	 * unique distances in the node_distance() table.
+	 *
+	 * Assumes node_distance(0,j) includes all distances in
+	 * node_distance(i,j) in order to avoid cubic time.
+	 */
+	next_distance = curr_distance;
+	for (i = 0; i < nr_node_ids; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			for (k = 0; k < nr_node_ids; k++) {
+				int distance = node_distance(i, k);
+
+				if (distance > curr_distance &&
+				    (distance < next_distance ||
+				     next_distance == curr_distance))
+					next_distance = distance;
+
+				/*
+				 * While not a strong assumption it would be nice to know
+				 * about cases where if node A is connected to B, B is not
+				 * equally connected to A.
+				 */
+				if (sched_debug() && node_distance(k, i) != distance)
+					sched_numa_warn("Node-distance not symmetric");
+
+				if (sched_debug() && i && !find_numa_distance(distance))
+					sched_numa_warn("Node-0 not representative");
+			}
+			if (next_distance != curr_distance) {
+				sched_domains_numa_distance[level++] = next_distance;
+				sched_domains_numa_levels = level;
+				curr_distance = next_distance;
+			} else break;
+		}
+
+		/*
+		 * In case of sched_debug() we verify the above assumption.
+		 */
+		if (!sched_debug())
+			break;
+	}
+	/*
+	 * 'level' contains the number of unique distances, excluding the
+	 * identity distance node_distance(i,i).
+	 *
+	 * The sched_domains_numa_distance[] array includes the actual distance
+	 * numbers.
+	 */
+
+	/*
+	 * Here, we should temporarily reset sched_domains_numa_levels to 0.
+	 * If it fails to allocate memory for array sched_domains_numa_masks[][],
+	 * the array will contain less then 'level' members. This could be
+	 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
+	 * in other functions.
+	 *
+	 * We reset it to 'level' at the end of this function.
+	 */
+	sched_domains_numa_levels = 0;
+
+	sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
+	if (!sched_domains_numa_masks)
+		return;
+
+	/*
+	 * Now for each level, construct a mask per node which contains all
+	 * cpus of nodes that are that many hops away from us.
+	 */
+	for (i = 0; i < level; i++) {
+		sched_domains_numa_masks[i] =
+			kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
+		if (!sched_domains_numa_masks[i])
+			return;
+
+		for (j = 0; j < nr_node_ids; j++) {
+			struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
+			if (!mask)
+				return;
+
+			sched_domains_numa_masks[i][j] = mask;
+
+			for_each_node(k) {
+				if (node_distance(j, k) > sched_domains_numa_distance[i])
+					continue;
+
+				cpumask_or(mask, mask, cpumask_of_node(k));
+			}
+		}
+	}
+
+	/* Compute default topology size */
+	for (i = 0; sched_domain_topology[i].mask; i++);
+
+	tl = kzalloc((i + level + 1) *
+			sizeof(struct sched_domain_topology_level), GFP_KERNEL);
+	if (!tl)
+		return;
+
+	/*
+	 * Copy the default topology bits..
+	 */
+	for (i = 0; sched_domain_topology[i].mask; i++)
+		tl[i] = sched_domain_topology[i];
+
+	/*
+	 * .. and append 'j' levels of NUMA goodness.
+	 */
+	for (j = 0; j < level; i++, j++) {
+		tl[i] = (struct sched_domain_topology_level){
+			.mask = sd_numa_mask,
+			.sd_flags = cpu_numa_flags,
+			.flags = SDTL_OVERLAP,
+			.numa_level = j,
+			SD_INIT_NAME(NUMA)
+		};
+	}
+
+	sched_domain_topology = tl;
+
+	sched_domains_numa_levels = level;
+}
+
+static void sched_domains_numa_masks_set(int cpu)
+{
+	int i, j;
+	int node = cpu_to_node(cpu);
+
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		for (j = 0; j < nr_node_ids; j++) {
+			if (node_distance(j, node) <= sched_domains_numa_distance[i])
+				cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
+		}
+	}
+}
+
+static void sched_domains_numa_masks_clear(int cpu)
+{
+	int i, j;
+	for (i = 0; i < sched_domains_numa_levels; i++) {
+		for (j = 0; j < nr_node_ids; j++)
+			cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
+	}
+}
+
+/*
+ * Update sched_domains_numa_masks[level][node] array when new cpus
+ * are onlined.
+ */
+static int sched_domains_numa_masks_update(struct notifier_block *nfb,
+					   unsigned long action,
+					   void *hcpu)
+{
+	int cpu = (long)hcpu;
+
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_ONLINE:
+		sched_domains_numa_masks_set(cpu);
+		break;
+
+	case CPU_DEAD:
+		sched_domains_numa_masks_clear(cpu);
+		break;
+
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
+#else
+static inline void sched_init_numa(void)
+{
+}
+
+static int sched_domains_numa_masks_update(struct notifier_block *nfb,
+					   unsigned long action,
+					   void *hcpu)
+{
+	return 0;
+}
+#endif /* CONFIG_NUMA */
+
+static int __sdt_alloc(const struct cpumask *cpu_map)
+{
+	struct sched_domain_topology_level *tl;
+	int j;
+
+	for_each_sd_topology(tl) {
+		struct sd_data *sdd = &tl->data;
+
+		sdd->sd = alloc_percpu(struct sched_domain *);
+		if (!sdd->sd)
+			return -ENOMEM;
+
+		for_each_cpu(j, cpu_map) {
+			struct sched_domain *sd;
+
+			sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
+					GFP_KERNEL, cpu_to_node(j));
+			if (!sd)
+				return -ENOMEM;
+
+			*per_cpu_ptr(sdd->sd, j) = sd;
+		}
+	}
+
+	return 0;
+}
+
+static void __sdt_free(const struct cpumask *cpu_map)
+{
+	struct sched_domain_topology_level *tl;
+	int j;
+
+	for_each_sd_topology(tl) {
+		struct sd_data *sdd = &tl->data;
+
+		for_each_cpu(j, cpu_map) {
+			struct sched_domain *sd;
+
+			if (sdd->sd) {
+				sd = *per_cpu_ptr(sdd->sd, j);
+				kfree(*per_cpu_ptr(sdd->sd, j));
+			}
+		}
+		free_percpu(sdd->sd);
+		sdd->sd = NULL;
+	}
+}
+
+struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
+		const struct cpumask *cpu_map, struct sched_domain_attr *attr,
+		struct sched_domain *child, int cpu)
+{
+	struct sched_domain *sd = sd_init(tl, cpu);
+	if (!sd)
+		return child;
+
+	cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
+	if (child) {
+		sd->level = child->level + 1;
+		sched_domain_level_max = max(sched_domain_level_max, sd->level);
+		child->parent = sd;
+		sd->child = child;
+
+		if (!cpumask_subset(sched_domain_span(child),
+				    sched_domain_span(sd))) {
+			pr_err("BUG: arch topology borken\n");
+#ifdef CONFIG_SCHED_DEBUG
+			pr_err("     the %s domain not a subset of the %s domain\n",
+					child->name, sd->name);
+#endif
+			/* Fixup, ensure @sd has at least @child cpus. */
+			cpumask_or(sched_domain_span(sd),
+				   sched_domain_span(sd),
+				   sched_domain_span(child));
+		}
+
+	}
+	set_domain_attribute(sd, attr);
+
+	return sd;
+}
+
+/*
+ * Build sched domains for a given set of cpus and attach the sched domains
+ * to the individual cpus
+ */
+static int build_sched_domains(const struct cpumask *cpu_map,
+			       struct sched_domain_attr *attr)
+{
+	enum s_alloc alloc_state;
+	struct sched_domain *sd;
+	struct s_data d;
+	int i, ret = -ENOMEM;
+
+	alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
+	if (alloc_state != sa_rootdomain)
+		goto error;
+
+	/* Set up domains for cpus specified by the cpu_map. */
+	for_each_cpu(i, cpu_map) {
+		struct sched_domain_topology_level *tl;
+
+		sd = NULL;
+		for_each_sd_topology(tl) {
+			sd = build_sched_domain(tl, cpu_map, attr, sd, i);
+			if (tl == sched_domain_topology)
+				*per_cpu_ptr(d.sd, i) = sd;
+			if (tl->flags & SDTL_OVERLAP)
+				sd->flags |= SD_OVERLAP;
+			if (cpumask_equal(cpu_map, sched_domain_span(sd)))
+				break;
+		}
+	}
+
+	/* Calculate CPU capacity for physical packages and nodes */
+	for (i = nr_cpumask_bits-1; i >= 0; i--) {
+		if (!cpumask_test_cpu(i, cpu_map))
+			continue;
+
+		for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+			claim_allocations(i, sd);
+		}
+	}
+
+	/* Attach the domains */
+	rcu_read_lock();
+	for_each_cpu(i, cpu_map) {
+		sd = *per_cpu_ptr(d.sd, i);
+		cpu_attach_domain(sd, d.rd, i);
+	}
+	rcu_read_unlock();
+
+	ret = 0;
+error:
+	__free_domain_allocs(&d, alloc_state, cpu_map);
+	return ret;
+}
+
+static cpumask_var_t *doms_cur;	/* current sched domains */
+static int ndoms_cur;		/* number of sched domains in 'doms_cur' */
+static struct sched_domain_attr *dattr_cur;
+				/* attribues of custom domains in 'doms_cur' */
+
+/*
+ * Special case: If a kmalloc of a doms_cur partition (array of
+ * cpumask) fails, then fallback to a single sched domain,
+ * as determined by the single cpumask fallback_doms.
+ */
+static cpumask_var_t fallback_doms;
+
+/*
+ * arch_update_cpu_topology lets virtualized architectures update the
+ * cpu core maps. It is supposed to return 1 if the topology changed
+ * or 0 if it stayed the same.
+ */
+int __weak arch_update_cpu_topology(void)
+{
+	return 0;
+}
+
+cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
+{
+	int i;
+	cpumask_var_t *doms;
+
+	doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
+	if (!doms)
+		return NULL;
+	for (i = 0; i < ndoms; i++) {
+		if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
+			free_sched_domains(doms, i);
+			return NULL;
+		}
+	}
+	return doms;
+}
+
+void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
+{
+	unsigned int i;
+	for (i = 0; i < ndoms; i++)
+		free_cpumask_var(doms[i]);
+	kfree(doms);
+}
+
+/*
+ * Set up scheduler domains and groups. Callers must hold the hotplug lock.
+ * For now this just excludes isolated cpus, but could be used to
+ * exclude other special cases in the future.
+ */
+static int init_sched_domains(const struct cpumask *cpu_map)
+{
+	int err;
+
+	arch_update_cpu_topology();
+	ndoms_cur = 1;
+	doms_cur = alloc_sched_domains(ndoms_cur);
+	if (!doms_cur)
+		doms_cur = &fallback_doms;
+	cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
+	err = build_sched_domains(doms_cur[0], NULL);
+	register_sched_domain_sysctl();
+
+	return err;
+}
+
+/*
+ * Detach sched domains from a group of cpus specified in cpu_map
+ * These cpus will now be attached to the NULL domain
+ */
+static void detach_destroy_domains(const struct cpumask *cpu_map)
+{
+	int i;
+
+	rcu_read_lock();
+	for_each_cpu(i, cpu_map)
+		cpu_attach_domain(NULL, &def_root_domain, i);
+	rcu_read_unlock();
+}
+
+/* handle null as "default" */
+static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
+			struct sched_domain_attr *new, int idx_new)
+{
+	struct sched_domain_attr tmp;
+
+	/* fast path */
+	if (!new && !cur)
+		return 1;
+
+	tmp = SD_ATTR_INIT;
+	return !memcmp(cur ? (cur + idx_cur) : &tmp,
+			new ? (new + idx_new) : &tmp,
+			sizeof(struct sched_domain_attr));
+}
+
+/*
+ * Partition sched domains as specified by the 'ndoms_new'
+ * cpumasks in the array doms_new[] of cpumasks. This compares
+ * doms_new[] to the current sched domain partitioning, doms_cur[].
+ * It destroys each deleted domain and builds each new domain.
+ *
+ * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
+ * The masks don't intersect (don't overlap.) We should setup one
+ * sched domain for each mask. CPUs not in any of the cpumasks will
+ * not be load balanced. If the same cpumask appears both in the
+ * current 'doms_cur' domains and in the new 'doms_new', we can leave
+ * it as it is.
+ *
+ * The passed in 'doms_new' should be allocated using
+ * alloc_sched_domains.  This routine takes ownership of it and will
+ * free_sched_domains it when done with it. If the caller failed the
+ * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
+ * and partition_sched_domains() will fallback to the single partition
+ * 'fallback_doms', it also forces the domains to be rebuilt.
+ *
+ * If doms_new == NULL it will be replaced with cpu_online_mask.
+ * ndoms_new == 0 is a special case for destroying existing domains,
+ * and it will not create the default domain.
+ *
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+			     struct sched_domain_attr *dattr_new)
+{
+	int i, j, n;
+	int new_topology;
+
+	mutex_lock(&sched_domains_mutex);
+
+	/* always unregister in case we don't destroy any domains */
+	unregister_sched_domain_sysctl();
+
+	/* Let architecture update cpu core mappings. */
+	new_topology = arch_update_cpu_topology();
+
+	n = doms_new ? ndoms_new : 0;
+
+	/* Destroy deleted domains */
+	for (i = 0; i < ndoms_cur; i++) {
+		for (j = 0; j < n && !new_topology; j++) {
+			if (cpumask_equal(doms_cur[i], doms_new[j])
+			    && dattrs_equal(dattr_cur, i, dattr_new, j))
+				goto match1;
+		}
+		/* no match - a current sched domain not in new doms_new[] */
+		detach_destroy_domains(doms_cur[i]);
+match1:
+		;
+	}
+
+	n = ndoms_cur;
+	if (doms_new == NULL) {
+		n = 0;
+		doms_new = &fallback_doms;
+		cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
+		WARN_ON_ONCE(dattr_new);
+	}
+
+	/* Build new domains */
+	for (i = 0; i < ndoms_new; i++) {
+		for (j = 0; j < n && !new_topology; j++) {
+			if (cpumask_equal(doms_new[i], doms_cur[j])
+			    && dattrs_equal(dattr_new, i, dattr_cur, j))
+				goto match2;
+		}
+		/* no match - add a new doms_new */
+		build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
+match2:
+		;
+	}
+
+	/* Remember the new sched domains */
+	if (doms_cur != &fallback_doms)
+		free_sched_domains(doms_cur, ndoms_cur);
+	kfree(dattr_cur);	/* kfree(NULL) is safe */
+	doms_cur = doms_new;
+	dattr_cur = dattr_new;
+	ndoms_cur = ndoms_new;
+
+	register_sched_domain_sysctl();
+
+	mutex_unlock(&sched_domains_mutex);
+}
+
+static int num_cpus_frozen;	/* used to mark begin/end of suspend/resume */
+
+/*
+ * Update cpusets according to cpu_active mask.  If cpusets are
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
+ * around partition_sched_domains().
+ *
+ * If we come here as part of a suspend/resume, don't touch cpusets because we
+ * want to restore it back to its original state upon resume anyway.
+ */
+static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
+			     void *hcpu)
+{
+	switch (action) {
+	case CPU_ONLINE_FROZEN:
+	case CPU_DOWN_FAILED_FROZEN:
+
+		/*
+		 * num_cpus_frozen tracks how many CPUs are involved in suspend
+		 * resume sequence. As long as this is not the last online
+		 * operation in the resume sequence, just build a single sched
+		 * domain, ignoring cpusets.
+		 */
+		num_cpus_frozen--;
+		if (likely(num_cpus_frozen)) {
+			partition_sched_domains(1, NULL, NULL);
+			break;
+		}
+
+		/*
+		 * This is the last CPU online operation. So fall through and
+		 * restore the original sched domains by considering the
+		 * cpuset configurations.
+		 */
+
+	case CPU_ONLINE:
+		cpuset_update_active_cpus(true);
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+	return NOTIFY_OK;
+}
+
+static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
+			       void *hcpu)
+{
+	switch (action) {
+	case CPU_DOWN_PREPARE:
+		cpuset_update_active_cpus(false);
+		break;
+	case CPU_DOWN_PREPARE_FROZEN:
+		num_cpus_frozen++;
+		partition_sched_domains(1, NULL, NULL);
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+	return NOTIFY_OK;
+}
+
+#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC)
+/*
+ * Cheaper version of the below functions in case support for SMT and MC is
+ * compiled in but CPUs have no siblings.
+ */
+static bool sole_cpu_idle(int cpu)
+{
+	return rq_idle(cpu_rq(cpu));
+}
+#endif
+#ifdef CONFIG_SCHED_SMT
+static const cpumask_t *thread_cpumask(int cpu)
+{
+	return topology_sibling_cpumask(cpu);
+}
+/* All this CPU's SMT siblings are idle */
+static bool siblings_cpu_idle(int cpu)
+{
+	return cpumask_subset(thread_cpumask(cpu), &grq.cpu_idle_map);
+}
+#endif
+#ifdef CONFIG_SCHED_MC
+static const cpumask_t *core_cpumask(int cpu)
+{
+	return topology_core_cpumask(cpu);
+}
+/* All this CPU's shared cache siblings are idle */
+static bool cache_cpu_idle(int cpu)
+{
+	return cpumask_subset(core_cpumask(cpu), &grq.cpu_idle_map);
+}
+#endif
+
+enum sched_domain_level {
+	SD_LV_NONE = 0,
+	SD_LV_SIBLING,
+	SD_LV_MC,
+	SD_LV_BOOK,
+	SD_LV_CPU,
+	SD_LV_NODE,
+	SD_LV_ALLNODES,
+	SD_LV_MAX
+};
+
+void __init sched_init_smp(void)
+{
+	struct sched_domain *sd;
+	int cpu, other_cpu;
+
+	cpumask_var_t non_isolated_cpus;
+
+	alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
+	alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
+
+	sched_init_numa();
+
+	/*
+	 * There's no userspace yet to cause hotplug operations; hence all the
+	 * cpu masks are stable and all blatant races in the below code cannot
+	 * happen.
+	 */
+	mutex_lock(&sched_domains_mutex);
+	init_sched_domains(cpu_active_mask);
+	cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
+	if (cpumask_empty(non_isolated_cpus))
+		cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
+	mutex_unlock(&sched_domains_mutex);
+
+	hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
+	hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
+	hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
+
+	/* Move init over to a non-isolated CPU */
+	if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
+		BUG();
+	free_cpumask_var(non_isolated_cpus);
+
+	mutex_lock(&sched_domains_mutex);
+	grq_lock_irq();
+	/*
+	 * Set up the relative cache distance of each online cpu from each
+	 * other in a simple array for quick lookup. Locality is determined
+	 * by the closest sched_domain that CPUs are separated by. CPUs with
+	 * shared cache in SMT and MC are treated as local. Separate CPUs
+	 * (within the same package or physically) within the same node are
+	 * treated as not local. CPUs not even in the same domain (different
+	 * nodes) are treated as very distant.
+	 */
+	for_each_online_cpu(cpu) {
+		struct rq *rq = cpu_rq(cpu);
+
+		/* First check if this cpu is in the same node */
+		for_each_domain(cpu, sd) {
+			if (sd->level > SD_LV_NODE)
+				continue;
+			/* Set locality to local node if not already found lower */
+			for_each_cpu(other_cpu, sched_domain_span(sd)) {
+				if (rq->cpu_locality[other_cpu] > 3)
+					rq->cpu_locality[other_cpu] = 3;
+			}
+		}
+
+		/*
+		 * Each runqueue has its own function in case it doesn't have
+		 * siblings of its own allowing mixed topologies.
+		 */
+#ifdef CONFIG_SCHED_MC
+		for_each_cpu(other_cpu, core_cpumask(cpu)) {
+			if (rq->cpu_locality[other_cpu] > 2)
+				rq->cpu_locality[other_cpu] = 2;
+		}
+		if (cpumask_weight(core_cpumask(cpu)) > 1)
+			rq->cache_idle = cache_cpu_idle;
+#endif
+#ifdef CONFIG_SCHED_SMT
+		for_each_cpu(other_cpu, thread_cpumask(cpu))
+			rq->cpu_locality[other_cpu] = 1;
+		if (cpumask_weight(thread_cpumask(cpu)) > 1)
+			rq->siblings_idle = siblings_cpu_idle;
+#endif
+	}
+	grq_unlock_irq();
+	mutex_unlock(&sched_domains_mutex);
+
+	for_each_online_cpu(cpu) {
+		struct rq *rq = cpu_rq(cpu);
+		for_each_online_cpu(other_cpu) {
+			if (other_cpu <= cpu)
+				continue;
+			printk(KERN_DEBUG "BFS LOCALITY CPU %d to %d: %d\n", cpu, other_cpu, rq->cpu_locality[other_cpu]);
+		}
+	}
+}
+#else
+void __init sched_init_smp(void)
+{
+}
+#endif /* CONFIG_SMP */
+
+int in_sched_functions(unsigned long addr)
+{
+	return in_lock_functions(addr) ||
+		(addr >= (unsigned long)__sched_text_start
+		&& addr < (unsigned long)__sched_text_end);
+}
+
+void __init sched_init(void)
+{
+#ifdef CONFIG_SMP
+	int cpu_ids;
+#endif
+	int i;
+	struct rq *rq;
+
+	prio_ratios[0] = 128;
+	for (i = 1 ; i < NICE_WIDTH ; i++)
+		prio_ratios[i] = prio_ratios[i - 1] * 11 / 10;
+
+	raw_spin_lock_init(&grq.lock);
+	grq.nr_running = grq.nr_uninterruptible = grq.nr_switches = 0;
+	grq.niffies = 0;
+	grq.last_jiffy = jiffies;
+	raw_spin_lock_init(&grq.iso_lock);
+	grq.iso_ticks = 0;
+	grq.iso_refractory = false;
+	grq.noc = 1;
+#ifdef CONFIG_SMP
+	init_defrootdomain();
+	grq.qnr = grq.idle_cpus = 0;
+	cpumask_clear(&grq.cpu_idle_map);
+#else
+	uprq = &per_cpu(runqueues, 0);
+#endif
+	for_each_possible_cpu(i) {
+		rq = cpu_rq(i);
+		rq->grq_lock = &grq.lock;
+		rq->user_pc = rq->nice_pc = rq->softirq_pc = rq->system_pc =
+			      rq->iowait_pc = rq->idle_pc = 0;
+		rq->dither = false;
+#ifdef CONFIG_SMP
+		rq->sticky_task = NULL;
+		rq->last_niffy = 0;
+		rq->sd = NULL;
+		rq->rd = NULL;
+		rq->online = false;
+		rq->cpu = i;
+		rq_attach_root(rq, &def_root_domain);
+#endif
+		atomic_set(&rq->nr_iowait, 0);
+	}
+
+#ifdef CONFIG_SMP
+	cpu_ids = i;
+	/*
+	 * Set the base locality for cpu cache distance calculation to
+	 * "distant" (3). Make sure the distance from a CPU to itself is 0.
+	 */
+	for_each_possible_cpu(i) {
+		int j;
+
+		rq = cpu_rq(i);
+#ifdef CONFIG_SCHED_SMT
+		rq->siblings_idle = sole_cpu_idle;
+#endif
+#ifdef CONFIG_SCHED_MC
+		rq->cache_idle = sole_cpu_idle;
+#endif
+		rq->cpu_locality = kmalloc(cpu_ids * sizeof(int *), GFP_ATOMIC);
+		for_each_possible_cpu(j) {
+			if (i == j)
+				rq->cpu_locality[j] = 0;
+			else
+				rq->cpu_locality[j] = 4;
+		}
+	}
+#endif
+
+	for (i = 0; i < PRIO_LIMIT; i++)
+		INIT_LIST_HEAD(grq.queue + i);
+	/* delimiter for bitsearch */
+	__set_bit(PRIO_LIMIT, grq.prio_bitmap);
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+	INIT_HLIST_HEAD(&init_task.preempt_notifiers);
+#endif
+
+	/*
+	 * The boot idle thread does lazy MMU switching as well:
+	 */
+	atomic_inc(&init_mm.mm_count);
+	enter_lazy_tlb(&init_mm, current);
+
+	/*
+	 * Make us the idle thread. Technically, schedule() should not be
+	 * called from this thread, however somewhere below it might be,
+	 * but because we are the idle thread, we just pick up running again
+	 * when this runqueue becomes "idle".
+	 */
+	init_idle(current, smp_processor_id());
+
+#ifdef CONFIG_SMP
+	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
+	/* May be allocated at isolcpus cmdline parse time */
+	if (cpu_isolated_map == NULL)
+		zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+	idle_thread_set_boot_cpu();
+#endif /* SMP */
+}
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+static inline int preempt_count_equals(int preempt_offset)
+{
+	int nested = preempt_count() + rcu_preempt_depth();
+
+	return (nested == preempt_offset);
+}
+
+void __might_sleep(const char *file, int line, int preempt_offset)
+{
+	/*
+	 * Blocking primitives will set (and therefore destroy) current->state,
+	 * since we will exit with TASK_RUNNING make sure we enter with it,
+	 * otherwise we will destroy state.
+	 */
+	WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
+			"do not call blocking ops when !TASK_RUNNING; "
+			"state=%lx set at [<%p>] %pS\n",
+			current->state,
+			(void *)current->task_state_change,
+			(void *)current->task_state_change);
+
+	___might_sleep(file, line, preempt_offset);
+}
+EXPORT_SYMBOL(__might_sleep);
+
+void ___might_sleep(const char *file, int line, int preempt_offset)
+{
+	static unsigned long prev_jiffy;	/* ratelimiting */
+
+	rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
+	if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
+	     !is_idle_task(current)) ||
+	    system_state != SYSTEM_RUNNING || oops_in_progress)
+		return;
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	printk(KERN_ERR
+		"BUG: sleeping function called from invalid context at %s:%d\n",
+			file, line);
+	printk(KERN_ERR
+		"in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+			in_atomic(), irqs_disabled(),
+			current->pid, current->comm);
+
+	if (task_stack_end_corrupted(current))
+		printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
+
+	debug_show_held_locks(current);
+	if (irqs_disabled())
+		print_irqtrace_events(current);
+#ifdef CONFIG_DEBUG_PREEMPT
+	if (!preempt_count_equals(preempt_offset)) {
+		pr_err("Preemption disabled at:");
+		print_ip_sym(current->preempt_disable_ip);
+		pr_cont("\n");
+	}
+#endif
+	dump_stack();
+}
+EXPORT_SYMBOL(___might_sleep);
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static inline void normalise_rt_tasks(void)
+{
+	struct task_struct *g, *p;
+	unsigned long flags;
+	struct rq *rq;
+	int queued;
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, p) {
+		/*
+		 * Only normalize user tasks:
+		 */
+		if (p->flags & PF_KTHREAD)
+			continue;
+
+		if (!rt_task(p) && !iso_task(p))
+			continue;
+
+		rq = task_grq_lock(p, &flags);
+		queued = task_queued(p);
+		if (queued)
+			dequeue_task(p);
+		__setscheduler(p, rq, SCHED_NORMAL, 0, false);
+		if (queued) {
+			enqueue_task(p, rq);
+			try_preempt(p, rq);
+		}
+
+		task_grq_unlock(&flags);
+	}
+	read_unlock(&tasklist_lock);
+}
+
+void normalize_rt_tasks(void)
+{
+	normalise_rt_tasks();
+}
+#endif /* CONFIG_MAGIC_SYSRQ */
+
+#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
+/*
+ * These functions are only useful for the IA64 MCA handling, or kdb.
+ *
+ * They can only be called when the whole system has been
+ * stopped - every CPU needs to be quiescent, and no scheduling
+ * activity can take place. Using them for anything else would
+ * be a serious bug, and as a result, they aren't even visible
+ * under any other configuration.
+ */
+
+/**
+ * curr_task - return the current task for a given cpu.
+ * @cpu: the processor in question.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ *
+ * Return: The current task for @cpu.
+ */
+struct task_struct *curr_task(int cpu)
+{
+	return cpu_curr(cpu);
+}
+
+#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
+
+#ifdef CONFIG_IA64
+/**
+ * set_curr_task - set the current task for a given cpu.
+ * @cpu: the processor in question.
+ * @p: the task pointer to set.
+ *
+ * Description: This function must only be used when non-maskable interrupts
+ * are serviced on a separate stack.  It allows the architecture to switch the
+ * notion of the current task on a cpu in a non-blocking manner.  This function
+ * must be called with all CPU's synchronised, and interrupts disabled, the
+ * and caller must save the original value of the current task (see
+ * curr_task() above) and restore that value before reenabling interrupts and
+ * re-starting the system.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ */
+void set_curr_task(int cpu, struct task_struct *p)
+{
+	cpu_curr(cpu) = p;
+}
+
+#endif
+
+/*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
+{
+	*ut = p->utime;
+	*st = p->stime;
+}
+EXPORT_SYMBOL_GPL(task_cputime_adjusted);
+
+void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputime(p, &cputime);
+
+	*ut = cputime.utime;
+	*st = cputime.stime;
+}
+
+void vtime_account_system_irqsafe(struct task_struct *tsk)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	vtime_account_system(tsk);
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(vtime_account_system_irqsafe);
+
+#ifndef __ARCH_HAS_VTIME_TASK_SWITCH
+void vtime_task_switch(struct task_struct *prev)
+{
+	if (is_idle_task(prev))
+		vtime_account_idle(prev);
+	else
+		vtime_account_system(prev);
+
+	vtime_account_user(prev);
+	arch_vtime_task_switch(prev);
+}
+#endif
+
+#else
+/*
+ * Perform (stime * rtime) / total, but avoid multiplication overflow by
+ * losing precision when the numbers are big.
+ */
+static cputime_t scale_stime(u64 stime, u64 rtime, u64 total)
+{
+	u64 scaled;
+
+	for (;;) {
+		/* Make sure "rtime" is the bigger of stime/rtime */
+		if (stime > rtime) {
+			u64 tmp = rtime; rtime = stime; stime = tmp;
+		}
+
+		/* Make sure 'total' fits in 32 bits */
+		if (total >> 32)
+			goto drop_precision;
+
+		/* Does rtime (and thus stime) fit in 32 bits? */
+		if (!(rtime >> 32))
+			break;
+
+		/* Can we just balance rtime/stime rather than dropping bits? */
+		if (stime >> 31)
+			goto drop_precision;
+
+		/* We can grow stime and shrink rtime and try to make them both fit */
+		stime <<= 1;
+		rtime >>= 1;
+		continue;
+
+drop_precision:
+		/* We drop from rtime, it has more bits than stime */
+		rtime >>= 1;
+		total >>= 1;
+	}
+
+	/*
+	 * Make sure gcc understands that this is a 32x32->64 multiply,
+	 * followed by a 64/32->64 divide.
+	 */
+	scaled = div_u64((u64) (u32) stime * (u64) (u32) rtime, (u32)total);
+	return (__force cputime_t) scaled;
+}
+
+/*
+ * Adjust tick based cputime random precision against scheduler
+ * runtime accounting.
+ */
+static void cputime_adjust(struct task_cputime *curr,
+			   struct prev_cputime *prev,
+			   cputime_t *ut, cputime_t *st)
+{
+	cputime_t rtime, stime, utime, total;
+
+	stime = curr->stime;
+	total = stime + curr->utime;
+
+	/*
+	 * Tick based cputime accounting depend on random scheduling
+	 * timeslices of a task to be interrupted or not by the timer.
+	 * Depending on these circumstances, the number of these interrupts
+	 * may be over or under-optimistic, matching the real user and system
+	 * cputime with a variable precision.
+	 *
+	 * Fix this by scaling these tick based values against the total
+	 * runtime accounted by the CFS scheduler.
+	 */
+	rtime = nsecs_to_cputime(curr->sum_exec_runtime);
+
+	/*
+	 * Update userspace visible utime/stime values only if actual execution
+	 * time is bigger than already exported. Note that can happen, that we
+	 * provided bigger values due to scaling inaccuracy on big numbers.
+	 */
+	if (prev->stime + prev->utime >= rtime)
+		goto out;
+
+	if (total) {
+		stime = scale_stime((__force u64)stime,
+				    (__force u64)rtime, (__force u64)total);
+		utime = rtime - stime;
+	} else {
+		stime = rtime;
+		utime = 0;
+	}
+
+	/*
+	 * If the tick based count grows faster than the scheduler one,
+	 * the result of the scaling may go backward.
+	 * Let's enforce monotonicity.
+	 */
+	prev->stime = max(prev->stime, stime);
+	prev->utime = max(prev->utime, utime);
+
+out:
+	*ut = prev->utime;
+	*st = prev->stime;
+}
+
+void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
+{
+	struct task_cputime cputime = {
+		.sum_exec_runtime = tsk_seruntime(p),
+	};
+
+	task_cputime(p, &cputime.utime, &cputime.stime);
+	cputime_adjust(&cputime, &p->prev_cputime, ut, st);
+}
+EXPORT_SYMBOL_GPL(task_cputime_adjusted);
+
+/*
+ * Must be called with siglock held.
+ */
+void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputime(p, &cputime);
+	cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
+}
+#endif
+
+void init_idle_bootup_task(struct task_struct *idle)
+{}
+
+#ifdef CONFIG_SCHED_DEBUG
+void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
+{}
+
+void proc_sched_set_task(struct task_struct *p)
+{}
+#endif
+
+#ifdef CONFIG_SMP
+#define SCHED_LOAD_SHIFT	(10)
+#define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)
+
+unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
+{
+	return SCHED_LOAD_SCALE;
+}
+
+unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
+{
+	unsigned long weight = cpumask_weight(sched_domain_span(sd));
+	unsigned long smt_gain = sd->smt_gain;
+
+	smt_gain /= weight;
+
+	return smt_gain;
+}
+#endif
diff --git a/kernel/sched/bfs_sched.h b/kernel/sched/bfs_sched.h
new file mode 100644
index 000000000..5d97f7919
--- /dev/null
+++ b/kernel/sched/bfs_sched.h
@@ -0,0 +1,181 @@
+#include <linux/sched.h>
+#include <linux/cpuidle.h>
+#include <linux/stop_machine.h>
+
+#ifndef BFS_SCHED_H
+#define BFS_SCHED_H
+
+/*
+ * This is the main, per-CPU runqueue data structure.
+ * This data should only be modified by the local cpu.
+ */
+struct rq {
+	struct task_struct *curr, *idle, *stop;
+	struct mm_struct *prev_mm;
+
+	/* Pointer to grq spinlock */
+	raw_spinlock_t *grq_lock;
+
+	/* Stored data about rq->curr to work outside grq lock */
+	u64 rq_deadline;
+	unsigned int rq_policy;
+	int rq_time_slice;
+	u64 rq_last_ran;
+	int rq_prio;
+	bool rq_running; /* There is a task running */
+	int soft_affined; /* Running or queued tasks with this set as their rq */
+#ifdef CONFIG_SMT_NICE
+	struct mm_struct *rq_mm;
+	int rq_smt_bias; /* Policy/nice level bias across smt siblings */
+#endif
+	/* Accurate timekeeping data */
+	u64 timekeep_clock;
+	unsigned long user_pc, nice_pc, irq_pc, softirq_pc, system_pc,
+		iowait_pc, idle_pc;
+	atomic_t nr_iowait;
+
+#ifdef CONFIG_SMP
+	int cpu;		/* cpu of this runqueue */
+	bool online;
+	bool scaling; /* This CPU is managed by a scaling CPU freq governor */
+	struct task_struct *sticky_task;
+
+	struct root_domain *rd;
+	struct sched_domain *sd;
+	int *cpu_locality; /* CPU relative cache distance */
+#ifdef CONFIG_SCHED_SMT
+	bool (*siblings_idle)(int cpu);
+	/* See if all smt siblings are idle */
+#endif /* CONFIG_SCHED_SMT */
+#ifdef CONFIG_SCHED_MC
+	bool (*cache_idle)(int cpu);
+	/* See if all cache siblings are idle */
+#endif /* CONFIG_SCHED_MC */
+	u64 last_niffy; /* Last time this RQ updated grq.niffies */
+#endif /* CONFIG_SMP */
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	u64 prev_irq_time;
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+#ifdef CONFIG_PARAVIRT
+	u64 prev_steal_time;
+#endif /* CONFIG_PARAVIRT */
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	u64 prev_steal_time_rq;
+#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */
+
+	u64 clock, old_clock, last_tick;
+	u64 clock_task;
+	bool dither;
+
+#ifdef CONFIG_SCHEDSTATS
+
+	/* latency stats */
+	struct sched_info rq_sched_info;
+	unsigned long long rq_cpu_time;
+	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
+
+	/* sys_sched_yield() stats */
+	unsigned int yld_count;
+
+	/* schedule() stats */
+	unsigned int sched_switch;
+	unsigned int sched_count;
+	unsigned int sched_goidle;
+
+	/* try_to_wake_up() stats */
+	unsigned int ttwu_count;
+	unsigned int ttwu_local;
+#endif /* CONFIG_SCHEDSTATS */
+#ifdef CONFIG_CPU_IDLE
+	/* Must be inspected within a rcu lock section */
+	struct cpuidle_state *idle_state;
+#endif
+};
+
+#ifdef CONFIG_SMP
+struct rq *cpu_rq(int cpu);
+#endif
+
+#ifndef CONFIG_SMP
+extern struct rq *uprq;
+#define cpu_rq(cpu)	(uprq)
+#define this_rq()	(uprq)
+#define raw_rq()	(uprq)
+#define task_rq(p)	(uprq)
+#define cpu_curr(cpu)	((uprq)->curr)
+#else /* CONFIG_SMP */
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+#define this_rq()		this_cpu_ptr(&runqueues)
+#define raw_rq()		raw_cpu_ptr(&runqueues)
+#endif /* CONFIG_SMP */
+
+static inline u64 __rq_clock_broken(struct rq *rq)
+{
+	return READ_ONCE(rq->clock);
+}
+
+static inline u64 rq_clock(struct rq *rq)
+{
+	lockdep_assert_held(rq->grq_lock);
+	return rq->clock;
+}
+
+static inline u64 rq_clock_task(struct rq *rq)
+{
+	lockdep_assert_held(rq->grq_lock);
+	return rq->clock_task;
+}
+
+extern struct mutex sched_domains_mutex;
+
+#define rcu_dereference_check_sched_domain(p) \
+	rcu_dereference_check((p), \
+			      lockdep_is_held(&sched_domains_mutex))
+
+/*
+ * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
+ * See detach_destroy_domains: synchronize_sched for details.
+ *
+ * The domain tree of any CPU may only be accessed from within
+ * preempt-disabled sections.
+ */
+#define for_each_domain(cpu, __sd) \
+	for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
+
+static inline void sched_ttwu_pending(void) { }
+
+static inline int task_on_rq_queued(struct task_struct *p)
+{
+	return p->on_rq;
+}
+
+#ifdef CONFIG_SMP
+
+extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask);
+
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+	rq->idle_state = idle_state;
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	WARN_ON(!rcu_read_lock_held());
+	return rq->idle_state;
+}
+#else
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	return NULL;
+}
+#endif
+#endif /* BFS_SCHED_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 05114b15b..544c98aac 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5378,6 +5378,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
 
 	case CPU_UP_PREPARE:
 		rq->calc_load_update = calc_load_update;
+		account_reset_rq(rq);
 		break;
 
 	case CPU_ONLINE:
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 544a7133c..bbf813929 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -13,7 +13,11 @@
 
 #include <trace/events/power.h>
 
+#ifdef CONFIG_SCHED_BFS
+#include "bfs_sched.h"
+#else
 #include "sched.h"
+#endif
 
 /**
  * sched_idle_set_state - Record idle state for the current CPU.
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index ef5875fff..60c5b6ba4 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1773,3 +1773,16 @@ static inline u64 irq_time_read(int cpu)
 }
 #endif /* CONFIG_64BIT */
 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+static inline void account_reset_rq(struct rq *rq)
+{
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	rq->prev_irq_time = 0;
+#endif
+#ifdef CONFIG_PARAVIRT
+	rq->prev_steal_time = 0;
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	rq->prev_steal_time_rq = 0;
+#endif
+}
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 87e2c9f0c..7466a0bb2 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -4,7 +4,11 @@
 #include <linux/seq_file.h>
 #include <linux/proc_fs.h>
 
+#ifndef CONFIG_SCHED_BFS
 #include "sched.h"
+#else
+#include "bfs_sched.h"
+#endif
 
 /*
  * bump this up when changing the output format or the meaning of an existing