1 files changed, 5004 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
new file mode 100644
index 000000000000..f69c4a5361e3
--- /dev/null
+++ b/kernel/sched.c
@@ -0,0 +1,5004 @@
+/*
+ *  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
+ */
+
+#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 <linux/smp_lock.h>
+#include <asm/mmu_context.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/kernel_stat.h>
+#include <linux/security.h>
+#include <linux/notifier.h>
+#include <linux/profile.h>
+#include <linux/suspend.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/percpu.h>
+#include <linux/kthread.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/times.h>
+#include <linux/acct.h>
+#include <asm/tlb.h>
+
+#include <asm/unistd.h>
+
+/*
+ * Convert user-nice values [ -20 ... 0 ... 19 ]
+ * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
+ * and back.
+ */
+#define NICE_TO_PRIO(nice)      (MAX_RT_PRIO + (nice) + 20)
+#define PRIO_TO_NICE(prio)      ((prio) - MAX_RT_PRIO - 20)
+#define TASK_NICE(p)            PRIO_TO_NICE((p)->static_prio)
+
+/*
+ * 'User priority' is the nice value converted to something we
+ * can work with better when scaling various scheduler parameters,
+ * it's a [ 0 ... 39 ] range.
+ */
+#define USER_PRIO(p)            ((p)-MAX_RT_PRIO)
+#define TASK_USER_PRIO(p)       USER_PRIO((p)->static_prio)
+#define MAX_USER_PRIO           (USER_PRIO(MAX_PRIO))
+
+/*
+ * Some helpers for converting nanosecond timing to jiffy resolution
+ */
+#define NS_TO_JIFFIES(TIME)     ((TIME) / (1000000000 / HZ))
+#define JIFFIES_TO_NS(TIME)     ((TIME) * (1000000000 / HZ))
+
+/*
+ * These are the 'tuning knobs' of the scheduler:
+ *
+ * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger),
+ * default timeslice is 100 msecs, maximum timeslice is 800 msecs.
+ * Timeslices get refilled after they expire.
+ */
+#define MIN_TIMESLICE           max(5 * HZ / 1000, 1)
+#define DEF_TIMESLICE           (100 * HZ / 1000)
+#define ON_RUNQUEUE_WEIGHT       30
+#define CHILD_PENALTY            95
+#define PARENT_PENALTY          100
+#define EXIT_WEIGHT               3
+#define PRIO_BONUS_RATIO         25
+#define MAX_BONUS               (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100)
+#define INTERACTIVE_DELTA         2
+#define MAX_SLEEP_AVG           (DEF_TIMESLICE * MAX_BONUS)
+#define STARVATION_LIMIT        (MAX_SLEEP_AVG)
+#define NS_MAX_SLEEP_AVG        (JIFFIES_TO_NS(MAX_SLEEP_AVG))
+
+/*
+ * If a task is 'interactive' then we reinsert it in the active
+ * array after it has expired its current timeslice. (it will not
+ * continue to run immediately, it will still roundrobin with
+ * other interactive tasks.)
+ *
+ * This part scales the interactivity limit depending on niceness.
+ *
+ * We scale it linearly, offset by the INTERACTIVE_DELTA delta.
+ * Here are a few examples of different nice levels:
+ *
+ *  TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0]
+ *  TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0]
+ *  TASK_INTERACTIVE(  0): [1,1,1,1,0,0,0,0,0,0,0]
+ *  TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0]
+ *  TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0]
+ *
+ * (the X axis represents the possible -5 ... 0 ... +5 dynamic
+ *  priority range a task can explore, a value of '1' means the
+ *  task is rated interactive.)
+ *
+ * Ie. nice +19 tasks can never get 'interactive' enough to be
+ * reinserted into the active array. And only heavily CPU-hog nice -20
+ * tasks will be expired. Default nice 0 tasks are somewhere between,
+ * it takes some effort for them to get interactive, but it's not
+ * too hard.
+ */
+
+#define CURRENT_BONUS(p) \
+        (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \
+                MAX_SLEEP_AVG)
+
+#define GRANULARITY     (10 * HZ / 1000 ? : 1)
+
+#ifdef CONFIG_SMP
+#define TIMESLICE_GRANULARITY(p)        (GRANULARITY * \
+                (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \
+                        num_online_cpus())
+#else
+#define TIMESLICE_GRANULARITY(p)        (GRANULARITY * \
+                (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)))
+#endif
+
+#define SCALE(v1,v1_max,v2_max) \
+        (v1) * (v2_max) / (v1_max)
+
+#define DELTA(p) \
+        (SCALE(TASK_NICE(p), 40, MAX_BONUS) + INTERACTIVE_DELTA)
+
+#define TASK_INTERACTIVE(p) \
+        ((p)->prio <= (p)->static_prio - DELTA(p))
+
+#define INTERACTIVE_SLEEP(p) \
+        (JIFFIES_TO_NS(MAX_SLEEP_AVG * \
+                (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1))
+
+#define TASK_PREEMPTS_CURR(p, rq) \
+        ((p)->prio < (rq)->curr->prio)
+
+/*
+ * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ]
+ * to time slice values: [800ms ... 100ms ... 5ms]
+ *
+ * The higher a thread's priority, the bigger timeslices
+ * it gets during one round of execution. But even the lowest
+ * priority thread gets MIN_TIMESLICE worth of execution time.
+ */
+
+#define SCALE_PRIO(x, prio) \
+        max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO/2), MIN_TIMESLICE)
+
+static inline unsigned int task_timeslice(task_t *p)
+{
+        if (p->static_prio < NICE_TO_PRIO(0))
+                return SCALE_PRIO(DEF_TIMESLICE*4, p->static_prio);
+        else
+                return SCALE_PRIO(DEF_TIMESLICE, p->static_prio);
+}
+#define task_hot(p, now, sd) ((long long) ((now) - (p)->last_ran)       \
+                                < (long long) (sd)->cache_hot_time)
+
+/*
+ * These are the runqueue data structures:
+ */
+
+#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
+
+typedef struct runqueue runqueue_t;
+
+struct prio_array {
+        unsigned int nr_active;
+        unsigned long bitmap[BITMAP_SIZE];
+        struct list_head queue[MAX_PRIO];
+};
+
+/*
+ * This is the main, per-CPU runqueue data structure.
+ *
+ * Locking rule: those places that want to lock multiple runqueues
+ * (such as the load balancing or the thread migration code), lock
+ * acquire operations must be ordered by ascending &runqueue.
+ */
+struct runqueue {
+        spinlock_t lock;
+
+        /*
+         * nr_running and cpu_load should be in the same cacheline because
+         * remote CPUs use both these fields when doing load calculation.
+         */
+        unsigned long nr_running;
+#ifdef CONFIG_SMP
+        unsigned long cpu_load;
+#endif
+        unsigned long long nr_switches;
+
+        /*
+         * This is part of a global counter where only the total sum
+         * over all CPUs matters. A task can increase this counter on
+         * one CPU and if it got migrated afterwards it may decrease
+         * it on another CPU. Always updated under the runqueue lock:
+         */
+        unsigned long nr_uninterruptible;
+
+        unsigned long expired_timestamp;
+        unsigned long long timestamp_last_tick;
+        task_t *curr, *idle;
+        struct mm_struct *prev_mm;
+        prio_array_t *active, *expired, arrays[2];
+        int best_expired_prio;
+        atomic_t nr_iowait;
+
+#ifdef CONFIG_SMP
+        struct sched_domain *sd;
+
+        /* For active balancing */
+        int active_balance;
+        int push_cpu;
+
+        task_t *migration_thread;
+        struct list_head migration_queue;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+        /* latency stats */
+        struct sched_info rq_sched_info;
+
+        /* sys_sched_yield() stats */
+        unsigned long yld_exp_empty;
+        unsigned long yld_act_empty;
+        unsigned long yld_both_empty;
+        unsigned long yld_cnt;
+
+        /* schedule() stats */
+        unsigned long sched_switch;
+        unsigned long sched_cnt;
+        unsigned long sched_goidle;
+
+        /* try_to_wake_up() stats */
+        unsigned long ttwu_cnt;
+        unsigned long ttwu_local;
+#endif
+};
+
+static DEFINE_PER_CPU(struct runqueue, runqueues);
+
+#define for_each_domain(cpu, domain) \
+        for (domain = cpu_rq(cpu)->sd; domain; domain = domain->parent)
+
+#define cpu_rq(cpu)             (&per_cpu(runqueues, (cpu)))
+#define this_rq()               (&__get_cpu_var(runqueues))
+#define task_rq(p)              cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)           (cpu_rq(cpu)->curr)
+
+/*
+ * Default context-switch locking:
+ */
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(rq, next)  do { } while (0)
+# define finish_arch_switch(rq, next)   spin_unlock_irq(&(rq)->lock)
+# define task_running(rq, p)            ((rq)->curr == (p))
+#endif
+
+/*
+ * task_rq_lock - lock the runqueue a given task resides on and disable
+ * interrupts.  Note the ordering: we can safely lookup the task_rq without
+ * explicitly disabling preemption.
+ */
+static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags)
+        __acquires(rq->lock)
+{
+        struct runqueue *rq;
+
+repeat_lock_task:
+        local_irq_save(*flags);
+        rq = task_rq(p);
+        spin_lock(&rq->lock);
+        if (unlikely(rq != task_rq(p))) {
+                spin_unlock_irqrestore(&rq->lock, *flags);
+                goto repeat_lock_task;
+        }
+        return rq;
+}
+
+static inline void task_rq_unlock(runqueue_t *rq, unsigned long *flags)
+        __releases(rq->lock)
+{
+        spin_unlock_irqrestore(&rq->lock, *flags);
+}
+
+#ifdef CONFIG_SCHEDSTATS
+/*
+ * bump this up when changing the output format or the meaning of an existing
+ * format, so that tools can adapt (or abort)
+ */
+#define SCHEDSTAT_VERSION 11
+
+static int show_schedstat(struct seq_file *seq, void *v)
+{
+        int cpu;
+
+        seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
+        seq_printf(seq, "timestamp %lu\n", jiffies);
+        for_each_online_cpu(cpu) {
+                runqueue_t *rq = cpu_rq(cpu);
+#ifdef CONFIG_SMP
+                struct sched_domain *sd;
+                int dcnt = 0;
+#endif
+
+                /* runqueue-specific stats */
+                seq_printf(seq,
+                    "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
+                    cpu, rq->yld_both_empty,
+                    rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt,
+                    rq->sched_switch, rq->sched_cnt, rq->sched_goidle,
+                    rq->ttwu_cnt, rq->ttwu_local,
+                    rq->rq_sched_info.cpu_time,
+                    rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt);
+
+                seq_printf(seq, "\n");
+
+#ifdef CONFIG_SMP
+                /* domain-specific stats */
+                for_each_domain(cpu, sd) {
+                        enum idle_type itype;
+                        char mask_str[NR_CPUS];
+
+                        cpumask_scnprintf(mask_str, NR_CPUS, sd->span);
+                        seq_printf(seq, "domain%d %s", dcnt++, mask_str);
+                        for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES;
+                                        itype++) {
+                                seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu",
+                                    sd->lb_cnt[itype],
+                                    sd->lb_balanced[itype],
+                                    sd->lb_failed[itype],
+                                    sd->lb_imbalance[itype],
+                                    sd->lb_gained[itype],
+                                    sd->lb_hot_gained[itype],
+                                    sd->lb_nobusyq[itype],
+                                    sd->lb_nobusyg[itype]);
+                        }
+                        seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu\n",
+                            sd->alb_cnt, sd->alb_failed, sd->alb_pushed,
+                            sd->sbe_pushed, sd->sbe_attempts,
+                            sd->ttwu_wake_remote, sd->ttwu_move_affine, sd->ttwu_move_balance);
+                }
+#endif
+        }
+        return 0;
+}
+
+static int schedstat_open(struct inode *inode, struct file *file)
+{
+        unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
+        char *buf = kmalloc(size, GFP_KERNEL);
+        struct seq_file *m;
+        int res;
+
+        if (!buf)
+                return -ENOMEM;
+        res = single_open(file, show_schedstat, NULL);
+        if (!res) {
+                m = file->private_data;
+                m->buf = buf;
+                m->size = size;
+        } else
+                kfree(buf);
+        return res;
+}
+
+struct file_operations proc_schedstat_operations = {
+        .open    = schedstat_open,
+        .read    = seq_read,
+        .llseek  = seq_lseek,
+        .release = single_release,
+};
+
+# define schedstat_inc(rq, field)       do { (rq)->field++; } while (0)
+# define schedstat_add(rq, field, amt)  do { (rq)->field += (amt); } while (0)
+#else /* !CONFIG_SCHEDSTATS */
+# define schedstat_inc(rq, field)       do { } while (0)
+# define schedstat_add(rq, field, amt)  do { } while (0)
+#endif
+
+/*
+ * rq_lock - lock a given runqueue and disable interrupts.
+ */
+static inline runqueue_t *this_rq_lock(void)
+        __acquires(rq->lock)
+{
+        runqueue_t *rq;
+
+        local_irq_disable();
+        rq = this_rq();
+        spin_lock(&rq->lock);
+
+        return rq;
+}
+
+#ifdef CONFIG_SCHED_SMT
+static int cpu_and_siblings_are_idle(int cpu)
+{
+        int sib;
+        for_each_cpu_mask(sib, cpu_sibling_map[cpu]) {
+                if (idle_cpu(sib))
+                        continue;
+                return 0;
+        }
+
+        return 1;
+}
+#else
+#define cpu_and_siblings_are_idle(A) idle_cpu(A)
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+/*
+ * Called when a process is dequeued from the active array and given
+ * the cpu.  We should note that with the exception of interactive
+ * tasks, the expired queue will become the active queue after the active
+ * queue is empty, without explicitly dequeuing and requeuing tasks in the
+ * expired queue.  (Interactive tasks may be requeued directly to the
+ * active queue, thus delaying tasks in the expired queue from running;
+ * see scheduler_tick()).
+ *
+ * This function is only called from sched_info_arrive(), rather than
+ * dequeue_task(). Even though a task may be queued and dequeued multiple
+ * times as it is shuffled about, we're really interested in knowing how
+ * long it was from the *first* time it was queued to the time that it
+ * finally hit a cpu.
+ */
+static inline void sched_info_dequeued(task_t *t)
+{
+        t->sched_info.last_queued = 0;
+}
+
+/*
+ * Called when a task finally hits the cpu.  We can now calculate how
+ * long it was waiting to run.  We also note when it began so that we
+ * can keep stats on how long its timeslice is.
+ */
+static inline void sched_info_arrive(task_t *t)
+{
+        unsigned long now = jiffies, diff = 0;
+        struct runqueue *rq = task_rq(t);
+
+        if (t->sched_info.last_queued)
+                diff = now - t->sched_info.last_queued;
+        sched_info_dequeued(t);
+        t->sched_info.run_delay += diff;
+        t->sched_info.last_arrival = now;
+        t->sched_info.pcnt++;
+
+        if (!rq)
+                return;
+
+        rq->rq_sched_info.run_delay += diff;
+        rq->rq_sched_info.pcnt++;
+}
+
+/*
+ * Called when a process is queued into either the active or expired
+ * array.  The time is noted and later used to determine how long we
+ * had to wait for us to reach the cpu.  Since the expired queue will
+ * become the active queue after active queue is empty, without dequeuing
+ * and requeuing any tasks, we are interested in queuing to either. It
+ * is unusual but not impossible for tasks to be dequeued and immediately
+ * requeued in the same or another array: this can happen in sched_yield(),
+ * set_user_nice(), and even load_balance() as it moves tasks from runqueue
+ * to runqueue.
+ *
+ * This function is only called from enqueue_task(), but also only updates
+ * the timestamp if it is already not set.  It's assumed that
+ * sched_info_dequeued() will clear that stamp when appropriate.
+ */
+static inline void sched_info_queued(task_t *t)
+{
+        if (!t->sched_info.last_queued)
+                t->sched_info.last_queued = jiffies;
+}
+
+/*
+ * Called when a process ceases being the active-running process, either
+ * voluntarily or involuntarily.  Now we can calculate how long we ran.
+ */
+static inline void sched_info_depart(task_t *t)
+{
+        struct runqueue *rq = task_rq(t);
+        unsigned long diff = jiffies - t->sched_info.last_arrival;
+
+        t->sched_info.cpu_time += diff;
+
+        if (rq)
+                rq->rq_sched_info.cpu_time += diff;
+}
+
+/*
+ * Called when tasks are switched involuntarily due, typically, to expiring
+ * their time slice.  (This may also be called when switching to or from
+ * the idle task.)  We are only called when prev != next.
+ */
+static inline void sched_info_switch(task_t *prev, task_t *next)
+{
+        struct runqueue *rq = task_rq(prev);
+
+        /*
+         * prev now departs the cpu.  It's not interesting to record
+         * stats about how efficient we were at scheduling the idle
+         * process, however.
+         */
+        if (prev != rq->idle)
+                sched_info_depart(prev);
+
+        if (next != rq->idle)
+                sched_info_arrive(next);
+}
+#else
+#define sched_info_queued(t)            do { } while (0)
+#define sched_info_switch(t, next)      do { } while (0)
+#endif /* CONFIG_SCHEDSTATS */
+
+/*
+ * Adding/removing a task to/from a priority array:
+ */
+static void dequeue_task(struct task_struct *p, prio_array_t *array)
+{
+        array->nr_active--;
+        list_del(&p->run_list);
+        if (list_empty(array->queue + p->prio))
+                __clear_bit(p->prio, array->bitmap);
+}
+
+static void enqueue_task(struct task_struct *p, prio_array_t *array)
+{
+        sched_info_queued(p);
+        list_add_tail(&p->run_list, array->queue + p->prio);
+        __set_bit(p->prio, array->bitmap);
+        array->nr_active++;
+        p->array = array;
+}
+
+/*
+ * Put task to the end of the run list without the overhead of dequeue
+ * followed by enqueue.
+ */
+static void requeue_task(struct task_struct *p, prio_array_t *array)
+{
+        list_move_tail(&p->run_list, array->queue + p->prio);
+}
+
+static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array)
+{
+        list_add(&p->run_list, array->queue + p->prio);
+        __set_bit(p->prio, array->bitmap);
+        array->nr_active++;
+        p->array = array;
+}
+
+/*
+ * effective_prio - return the priority that is based on the static
+ * priority but is modified by bonuses/penalties.
+ *
+ * We scale the actual sleep average [0 .... MAX_SLEEP_AVG]
+ * into the -5 ... 0 ... +5 bonus/penalty range.
+ *
+ * We use 25% of the full 0...39 priority range so that:
+ *
+ * 1) nice +19 interactive tasks do not preempt nice 0 CPU hogs.
+ * 2) nice -20 CPU hogs do not get preempted by nice 0 tasks.
+ *
+ * Both properties are important to certain workloads.
+ */
+static int effective_prio(task_t *p)
+{
+        int bonus, prio;
+
+        if (rt_task(p))
+                return p->prio;
+
+        bonus = CURRENT_BONUS(p) - MAX_BONUS / 2;
+
+        prio = p->static_prio - bonus;
+        if (prio < MAX_RT_PRIO)
+                prio = MAX_RT_PRIO;
+        if (prio > MAX_PRIO-1)
+                prio = MAX_PRIO-1;
+        return prio;
+}
+
+/*
+ * __activate_task - move a task to the runqueue.
+ */
+static inline void __activate_task(task_t *p, runqueue_t *rq)
+{
+        enqueue_task(p, rq->active);
+        rq->nr_running++;
+}
+
+/*
+ * __activate_idle_task - move idle task to the _front_ of runqueue.
+ */
+static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
+{
+        enqueue_task_head(p, rq->active);
+        rq->nr_running++;
+}
+
+static void recalc_task_prio(task_t *p, unsigned long long now)
+{
+        /* Caller must always ensure 'now >= p->timestamp' */
+        unsigned long long __sleep_time = now - p->timestamp;
+        unsigned long sleep_time;
+
+        if (__sleep_time > NS_MAX_SLEEP_AVG)
+                sleep_time = NS_MAX_SLEEP_AVG;
+        else
+                sleep_time = (unsigned long)__sleep_time;
+
+        if (likely(sleep_time > 0)) {
+                /*
+                 * User tasks that sleep a long time are categorised as
+                 * idle and will get just interactive status to stay active &
+                 * prevent them suddenly becoming cpu hogs and starving
+                 * other processes.
+                 */
+                if (p->mm && p->activated != -1 &&
+                        sleep_time > INTERACTIVE_SLEEP(p)) {
+                                p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG -
+                                                DEF_TIMESLICE);
+                } else {
+                        /*
+                         * The lower the sleep avg a task has the more
+                         * rapidly it will rise with sleep time.
+                         */
+                        sleep_time *= (MAX_BONUS - CURRENT_BONUS(p)) ? : 1;
+
+                        /*
+                         * Tasks waking from uninterruptible sleep are
+                         * limited in their sleep_avg rise as they
+                         * are likely to be waiting on I/O
+                         */
+                        if (p->activated == -1 && p->mm) {
+                                if (p->sleep_avg >= INTERACTIVE_SLEEP(p))
+                                        sleep_time = 0;
+                                else if (p->sleep_avg + sleep_time >=
+                                                INTERACTIVE_SLEEP(p)) {
+                                        p->sleep_avg = INTERACTIVE_SLEEP(p);
+                                        sleep_time = 0;
+                                }
+                        }
+
+                        /*
+                         * This code gives a bonus to interactive tasks.
+                         *
+                         * The boost works by updating the 'average sleep time'
+                         * value here, based on ->timestamp. The more time a
+                         * task spends sleeping, the higher the average gets -
+                         * and the higher the priority boost gets as well.
+                         */
+                        p->sleep_avg += sleep_time;
+
+                        if (p->sleep_avg > NS_MAX_SLEEP_AVG)
+                                p->sleep_avg = NS_MAX_SLEEP_AVG;
+                }
+        }
+
+        p->prio = effective_prio(p);
+}
+
+/*
+ * activate_task - move a task to the runqueue and do priority recalculation
+ *
+ * Update all the scheduling statistics stuff. (sleep average
+ * calculation, priority modifiers, etc.)
+ */
+static void activate_task(task_t *p, runqueue_t *rq, int local)
+{
+        unsigned long long now;
+
+        now = sched_clock();
+#ifdef CONFIG_SMP
+        if (!local) {
+                /* Compensate for drifting sched_clock */
+                runqueue_t *this_rq = this_rq();
+                now = (now - this_rq->timestamp_last_tick)
+                        + rq->timestamp_last_tick;
+        }
+#endif
+
+        recalc_task_prio(p, now);
+
+        /*
+         * This checks to make sure it's not an uninterruptible task
+         * that is now waking up.
+         */
+        if (!p->activated) {
+                /*
+                 * Tasks which were woken up by interrupts (ie. hw events)
+                 * are most likely of interactive nature. So we give them
+                 * the credit of extending their sleep time to the period
+                 * of time they spend on the runqueue, waiting for execution
+                 * on a CPU, first time around:
+                 */
+                if (in_interrupt())
+                        p->activated = 2;
+                else {
+                        /*
+                         * Normal first-time wakeups get a credit too for
+                         * on-runqueue time, but it will be weighted down:
+                         */
+                        p->activated = 1;
+                }
+        }
+        p->timestamp = now;
+
+        __activate_task(p, rq);
+}
+
+/*
+ * deactivate_task - remove a task from the runqueue.
+ */
+static void deactivate_task(struct task_struct *p, runqueue_t *rq)
+{
+        rq->nr_running--;
+        dequeue_task(p, p->array);
+        p->array = NULL;
+}
+
+/*
+ * 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.
+ */
+#ifdef CONFIG_SMP
+static void resched_task(task_t *p)
+{
+        int need_resched, nrpolling;
+
+        assert_spin_locked(&task_rq(p)->lock);
+
+        /* minimise the chance of sending an interrupt to poll_idle() */
+        nrpolling = test_tsk_thread_flag(p,TIF_POLLING_NRFLAG);
+        need_resched = test_and_set_tsk_thread_flag(p,TIF_NEED_RESCHED);
+        nrpolling |= test_tsk_thread_flag(p,TIF_POLLING_NRFLAG);
+
+        if (!need_resched && !nrpolling && (task_cpu(p) != smp_processor_id()))
+                smp_send_reschedule(task_cpu(p));
+}
+#else
+static inline void resched_task(task_t *p)
+{
+        set_tsk_need_resched(p);
+}
+#endif
+
+/**
+ * task_curr - is this task currently executing on a CPU?
+ * @p: the task in question.
+ */
+inline int task_curr(const task_t *p)
+{
+        return cpu_curr(task_cpu(p)) == p;
+}
+
+#ifdef CONFIG_SMP
+enum request_type {
+        REQ_MOVE_TASK,
+        REQ_SET_DOMAIN,
+};
+
+typedef struct {
+        struct list_head list;
+        enum request_type type;
+
+        /* For REQ_MOVE_TASK */
+        task_t *task;
+        int dest_cpu;
+
+        /* For REQ_SET_DOMAIN */
+        struct sched_domain *sd;
+
+        struct completion done;
+} migration_req_t;
+
+/*
+ * The task's runqueue lock must be held.
+ * Returns true if you have to wait for migration thread.
+ */
+static int migrate_task(task_t *p, int dest_cpu, migration_req_t *req)
+{
+        runqueue_t *rq = task_rq(p);
+
+        /*
+         * If the task is not on a runqueue (and not running), then
+         * it is sufficient to simply update the task's cpu field.
+         */
+        if (!p->array && !task_running(rq, p)) {
+                set_task_cpu(p, dest_cpu);
+                return 0;
+        }
+
+        init_completion(&req->done);
+        req->type = REQ_MOVE_TASK;
+        req->task = p;
+        req->dest_cpu = dest_cpu;
+        list_add(&req->list, &rq->migration_queue);
+        return 1;
+}
+
+/*
+ * wait_task_inactive - wait for a thread to unschedule.
+ *
+ * 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.
+ */
+void wait_task_inactive(task_t * p)
+{
+        unsigned long flags;
+        runqueue_t *rq;
+        int preempted;
+
+repeat:
+        rq = task_rq_lock(p, &flags);
+        /* Must be off runqueue entirely, not preempted. */
+        if (unlikely(p->array || task_running(rq, p))) {
+                /* If it's preempted, we yield.  It could be a while. */
+                preempted = !task_running(rq, p);
+                task_rq_unlock(rq, &flags);
+                cpu_relax();
+                if (preempted)
+                        yield();
+                goto repeat;
+        }
+        task_rq_unlock(rq, &flags);
+}
+
+/***
+ * 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 doesnt 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(task_t *p)
+{
+        int cpu;
+
+        preempt_disable();
+        cpu = task_cpu(p);
+        if ((cpu != smp_processor_id()) && task_curr(p))
+                smp_send_reschedule(cpu);
+        preempt_enable();
+}
+
+/*
+ * Return a low guess at the load of a migration-source cpu.
+ *
+ * We want to under-estimate the load of migration sources, to
+ * balance conservatively.
+ */
+static inline unsigned long source_load(int cpu)
+{
+        runqueue_t *rq = cpu_rq(cpu);
+        unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
+
+        return min(rq->cpu_load, load_now);
+}
+
+/*
+ * Return a high guess at the load of a migration-target cpu
+ */
+static inline unsigned long target_load(int cpu)
+{
+        runqueue_t *rq = cpu_rq(cpu);
+        unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
+
+        return max(rq->cpu_load, load_now);
+}
+
+#endif
+
+/*
+ * wake_idle() will wake a task on an idle cpu if task->cpu is
+ * not idle and an idle cpu is available.  The span of cpus to
+ * search starts with cpus closest then further out as needed,
+ * so we always favor a closer, idle cpu.
+ *
+ * Returns the CPU we should wake onto.
+ */
+#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
+static int wake_idle(int cpu, task_t *p)
+{
+        cpumask_t tmp;
+        struct sched_domain *sd;
+        int i;
+
+        if (idle_cpu(cpu))
+                return cpu;
+
+        for_each_domain(cpu, sd) {
+                if (sd->flags & SD_WAKE_IDLE) {
+                        cpus_and(tmp, sd->span, cpu_online_map);
+                        cpus_and(tmp, tmp, p->cpus_allowed);
+                        for_each_cpu_mask(i, tmp) {
+                                if (idle_cpu(i))
+                                        return i;
+                        }
+                }
+                else break;
+        }
+        return cpu;
+}
+#else
+static inline int wake_idle(int cpu, task_t *p)
+{
+        return cpu;
+}
+#endif
+
+/***
+ * try_to_wake_up - wake up a thread
+ * @p: the to-be-woken-up thread
+ * @state: the mask of task states that can be woken
+ * @sync: do a synchronous wakeup?
+ *
+ * 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.
+ *
+ * returns failure only if the task is already active.
+ */
+static int try_to_wake_up(task_t * p, unsigned int state, int sync)
+{
+        int cpu, this_cpu, success = 0;
+        unsigned long flags;
+        long old_state;
+        runqueue_t *rq;
+#ifdef CONFIG_SMP
+        unsigned long load, this_load;
+        struct sched_domain *sd;
+        int new_cpu;
+#endif
+
+        rq = task_rq_lock(p, &flags);
+        old_state = p->state;
+        if (!(old_state & state))
+                goto out;
+
+        if (p->array)
+                goto out_running;
+
+        cpu = task_cpu(p);
+        this_cpu = smp_processor_id();
+
+#ifdef CONFIG_SMP
+        if (unlikely(task_running(rq, p)))
+                goto out_activate;
+
+#ifdef CONFIG_SCHEDSTATS
+        schedstat_inc(rq, ttwu_cnt);
+        if (cpu == this_cpu) {
+                schedstat_inc(rq, ttwu_local);
+        } else {
+                for_each_domain(this_cpu, sd) {
+                        if (cpu_isset(cpu, sd->span)) {
+                                schedstat_inc(sd, ttwu_wake_remote);
+                                break;
+                        }
+                }
+        }
+#endif
+
+        new_cpu = cpu;
+        if (cpu == this_cpu || unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
+                goto out_set_cpu;
+
+        load = source_load(cpu);
+        this_load = target_load(this_cpu);
+
+        /*
+         * If sync wakeup then subtract the (maximum possible) effect of
+         * the currently running task from the load of the current CPU:
+         */
+        if (sync)
+                this_load -= SCHED_LOAD_SCALE;
+
+        /* Don't pull the task off an idle CPU to a busy one */
+        if (load < SCHED_LOAD_SCALE/2 && this_load > SCHED_LOAD_SCALE/2)
+                goto out_set_cpu;
+
+        new_cpu = this_cpu; /* Wake to this CPU if we can */
+
+        /*
+         * Scan domains for affine wakeup and passive balancing
+         * possibilities.
+         */
+        for_each_domain(this_cpu, sd) {
+                unsigned int imbalance;
+                /*
+                 * Start passive balancing when half the imbalance_pct
+                 * limit is reached.
+                 */
+                imbalance = sd->imbalance_pct + (sd->imbalance_pct - 100) / 2;
+
+                if ((sd->flags & SD_WAKE_AFFINE) &&
+                                !task_hot(p, rq->timestamp_last_tick, sd)) {
+                        /*
+                         * This domain has SD_WAKE_AFFINE and p is cache cold
+                         * in this domain.
+                         */
+                        if (cpu_isset(cpu, sd->span)) {
+                                schedstat_inc(sd, ttwu_move_affine);
+                                goto out_set_cpu;
+                        }
+                } else if ((sd->flags & SD_WAKE_BALANCE) &&
+                                imbalance*this_load <= 100*load) {
+                        /*
+                         * This domain has SD_WAKE_BALANCE and there is
+                         * an imbalance.
+                         */
+                        if (cpu_isset(cpu, sd->span)) {
+                                schedstat_inc(sd, ttwu_move_balance);
+                                goto out_set_cpu;
+                        }
+                }
+        }
+
+        new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
+out_set_cpu:
+        new_cpu = wake_idle(new_cpu, p);
+        if (new_cpu != cpu) {
+                set_task_cpu(p, new_cpu);
+                task_rq_unlock(rq, &flags);
+                /* might preempt at this point */
+                rq = task_rq_lock(p, &flags);
+                old_state = p->state;
+                if (!(old_state & state))
+                        goto out;
+                if (p->array)
+                        goto out_running;
+
+                this_cpu = smp_processor_id();
+                cpu = task_cpu(p);
+        }
+
+out_activate:
+#endif /* CONFIG_SMP */
+        if (old_state == TASK_UNINTERRUPTIBLE) {
+                rq->nr_uninterruptible--;
+                /*
+                 * Tasks on involuntary sleep don't earn
+                 * sleep_avg beyond just interactive state.
+                 */
+                p->activated = -1;
+        }
+
+        /*
+         * 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 the woken up task will run on
+         * this cpu. (in this case the 'I will reschedule' promise of
+         * the waker guarantees that the freshly woken up task is going
+         * to be considered on this CPU.)
+         */
+        activate_task(p, rq, cpu == this_cpu);
+        if (!sync || cpu != this_cpu) {
+                if (TASK_PREEMPTS_CURR(p, rq))
+                        resched_task(rq->curr);
+        }
+        success = 1;
+
+out_running:
+        p->state = TASK_RUNNING;
+out:
+        task_rq_unlock(rq, &flags);
+
+        return success;
+}
+
+int fastcall wake_up_process(task_t * p)
+{
+        return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED |
+                                 TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0);
+}
+
+EXPORT_SYMBOL(wake_up_process);
+
+int fastcall wake_up_state(task_t *p, unsigned int state)
+{
+        return try_to_wake_up(p, state, 0);
+}
+
+#ifdef CONFIG_SMP
+static int find_idlest_cpu(struct task_struct *p, int this_cpu,
+                           struct sched_domain *sd);
+#endif
+
+/*
+ * Perform scheduler related setup for a newly forked process p.
+ * p is forked by current.
+ */
+void fastcall sched_fork(task_t *p)
+{
+        /*
+         * We mark the process as running here, but have not actually
+         * inserted it onto the runqueue yet. 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.
+         */
+        p->state = TASK_RUNNING;
+        INIT_LIST_HEAD(&p->run_list);
+        p->array = NULL;
+        spin_lock_init(&p->switch_lock);
+#ifdef CONFIG_SCHEDSTATS
+        memset(&p->sched_info, 0, sizeof(p->sched_info));
+#endif
+#ifdef CONFIG_PREEMPT
+        /*
+         * During context-switch we hold precisely one spinlock, which
+         * schedule_tail drops. (in the common case it's this_rq()->lock,
+         * but it also can be p->switch_lock.) So we compensate with a count
+         * of 1. Also, we want to start with kernel preemption disabled.
+         */
+        p->thread_info->preempt_count = 1;
+#endif
+        /*
+         * 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.
+         */
+        local_irq_disable();
+        p->time_slice = (current->time_slice + 1) >> 1;
+        /*
+         * The remainder of the first timeslice might be recovered by
+         * the parent if the child exits early enough.
+         */
+        p->first_time_slice = 1;
+        current->time_slice >>= 1;
+        p->timestamp = sched_clock();
+        if (unlikely(!current->time_slice)) {
+                /*
+                 * This case is rare, it happens when the parent has only
+                 * a single jiffy left from its timeslice. Taking the
+                 * runqueue lock is not a problem.
+                 */
+                current->time_slice = 1;
+                preempt_disable();
+                scheduler_tick();
+                local_irq_enable();
+                preempt_enable();
+        } else
+                local_irq_enable();
+}
+
+/*
+ * 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 fastcall wake_up_new_task(task_t * p, unsigned long clone_flags)
+{
+        unsigned long flags;
+        int this_cpu, cpu;
+        runqueue_t *rq, *this_rq;
+
+        rq = task_rq_lock(p, &flags);
+        cpu = task_cpu(p);
+        this_cpu = smp_processor_id();
+
+        BUG_ON(p->state != TASK_RUNNING);
+
+        /*
+         * We decrease the sleep average of forking parents
+         * and children as well, to keep max-interactive tasks
+         * from forking tasks that are max-interactive. The parent
+         * (current) is done further down, under its lock.
+         */
+        p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) *
+                CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS);
+
+        p->prio = effective_prio(p);
+
+        if (likely(cpu == this_cpu)) {
+                if (!(clone_flags & CLONE_VM)) {
+                        /*
+                         * 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.
+                         */
+                        if (unlikely(!current->array))
+                                __activate_task(p, rq);
+                        else {
+                                p->prio = current->prio;
+                                list_add_tail(&p->run_list, &current->run_list);
+                                p->array = current->array;
+                                p->array->nr_active++;
+                                rq->nr_running++;
+                        }
+                        set_need_resched();
+                } else
+                        /* Run child last */
+                        __activate_task(p, rq);
+                /*
+                 * We skip the following code due to cpu == this_cpu
+                 *
+                 *   task_rq_unlock(rq, &flags);
+                 *   this_rq = task_rq_lock(current, &flags);
+                 */
+                this_rq = rq;
+        } else {
+                this_rq = cpu_rq(this_cpu);
+
+                /*
+                 * Not the local CPU - must adjust timestamp. This should
+                 * get optimised away in the !CONFIG_SMP case.
+                 */
+                p->timestamp = (p->timestamp - this_rq->timestamp_last_tick)
+                                        + rq->timestamp_last_tick;
+                __activate_task(p, rq);
+                if (TASK_PREEMPTS_CURR(p, rq))
+                        resched_task(rq->curr);
+
+                /*
+                 * Parent and child are on different CPUs, now get the
+                 * parent runqueue to update the parent's ->sleep_avg:
+                 */
+                task_rq_unlock(rq, &flags);
+                this_rq = task_rq_lock(current, &flags);
+        }
+        current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) *
+                PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS);
+        task_rq_unlock(this_rq, &flags);
+}
+
+/*
+ * Potentially available exiting-child timeslices are
+ * retrieved here - this way the parent does not get
+ * penalized for creating too many threads.
+ *
+ * (this cannot be used to 'generate' timeslices
+ * artificially, because any timeslice recovered here
+ * was given away by the parent in the first place.)
+ */
+void fastcall sched_exit(task_t * p)
+{
+        unsigned long flags;
+        runqueue_t *rq;
+
+        /*
+         * If the child was a (relative-) CPU hog then decrease
+         * the sleep_avg of the parent as well.
+         */
+        rq = task_rq_lock(p->parent, &flags);
+        if (p->first_time_slice) {
+                p->parent->time_slice += p->time_slice;
+                if (unlikely(p->parent->time_slice > task_timeslice(p)))
+                        p->parent->time_slice = task_timeslice(p);
+        }
+        if (p->sleep_avg < p->parent->sleep_avg)
+                p->parent->sleep_avg = p->parent->sleep_avg /
+                (EXIT_WEIGHT + 1) * EXIT_WEIGHT + p->sleep_avg /
+                (EXIT_WEIGHT + 1);
+        task_rq_unlock(rq, &flags);
+}
+
+/**
+ * finish_task_switch - clean up after a task-switch
+ * @prev: the thread we just switched away from.
+ *
+ * We enter this with the runqueue still locked, and finish_arch_switch()
+ * will unlock it along with doing 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.)
+ */
+static inline void finish_task_switch(task_t *prev)
+        __releases(rq->lock)
+{
+        runqueue_t *rq = this_rq();
+        struct mm_struct *mm = rq->prev_mm;
+        unsigned long prev_task_flags;
+
+        rq->prev_mm = NULL;
+
+        /*
+         * A task struct has one reference for the use as "current".
+         * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and
+         * calls schedule one last time. The schedule call will never return,
+         * and the scheduled task must drop that reference.
+         * The test for EXIT_ZOMBIE must occur while the runqueue locks are
+         * still held, otherwise prev could be scheduled on another cpu, die
+         * there before we look at prev->state, and then the reference would
+         * be dropped twice.
+         *              Manfred Spraul <manfred@colorfullife.com>
+         */
+        prev_task_flags = prev->flags;
+        finish_arch_switch(rq, prev);
+        if (mm)
+                mmdrop(mm);
+        if (unlikely(prev_task_flags & PF_DEAD))
+                put_task_struct(prev);
+}
+
+/**
+ * schedule_tail - first thing a freshly forked thread must call.
+ * @prev: the thread we just switched away from.
+ */
+asmlinkage void schedule_tail(task_t *prev)
+        __releases(rq->lock)
+{
+        finish_task_switch(prev);
+
+        if (current->set_child_tid)
+                put_user(current->pid, current->set_child_tid);
+}
+
+/*
+ * context_switch - switch to the new MM and the new
+ * thread's register state.
+ */
+static inline
+task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next)
+{
+        struct mm_struct *mm = next->mm;
+        struct mm_struct *oldmm = prev->active_mm;
+
+        if (unlikely(!mm)) {
+                next->active_mm = oldmm;
+                atomic_inc(&oldmm->mm_count);
+                enter_lazy_tlb(oldmm, next);
+        } else
+                switch_mm(oldmm, mm, next);
+
+        if (unlikely(!prev->mm)) {
+                prev->active_mm = NULL;
+                WARN_ON(rq->prev_mm);
+                rq->prev_mm = oldmm;
+        }
+
+        /* Here we just switch the register state and the stack. */
+        switch_to(prev, next, prev);
+
+        return prev;
+}
+
+/*
+ * nr_running, nr_uninterruptible and nr_context_switches:
+ *
+ * externally visible scheduler statistics: current number of runnable
+ * threads, current number of uninterruptible-sleeping threads, total
+ * number of context switches performed since bootup.
+ */
+unsigned long nr_running(void)
+{
+        unsigned long i, sum = 0;
+
+        for_each_online_cpu(i)
+                sum += cpu_rq(i)->nr_running;
+
+        return sum;
+}
+
+unsigned long nr_uninterruptible(void)
+{
+        unsigned long i, sum = 0;
+
+        for_each_cpu(i)
+                sum += cpu_rq(i)->nr_uninterruptible;
+
+        /*
+         * Since we read the counters lockless, it might be slightly
+         * inaccurate. Do not allow it to go below zero though:
+         */
+        if (unlikely((long)sum < 0))
+                sum = 0;
+
+        return sum;
+}
+
+unsigned long long nr_context_switches(void)
+{
+        unsigned long long i, sum = 0;
+
+        for_each_cpu(i)
+                sum += cpu_rq(i)->nr_switches;
+
+        return sum;
+}
+
+unsigned long nr_iowait(void)
+{
+        unsigned long i, sum = 0;
+
+        for_each_cpu(i)
+                sum += atomic_read(&cpu_rq(i)->nr_iowait);
+
+        return sum;
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * double_rq_lock - safely lock two runqueues
+ *
+ * Note this does not disable interrupts like task_rq_lock,
+ * you need to do so manually before calling.
+ */
+static void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
+        __acquires(rq1->lock)
+        __acquires(rq2->lock)
+{
+        if (rq1 == rq2) {
+                spin_lock(&rq1->lock);
+                __acquire(rq2->lock);   /* Fake it out ;) */
+        } else {
+                if (rq1 < rq2) {
+                        spin_lock(&rq1->lock);
+                        spin_lock(&rq2->lock);
+                } else {
+                        spin_lock(&rq2->lock);
+                        spin_lock(&rq1->lock);
+                }
+        }
+}
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2)
+        __releases(rq1->lock)
+        __releases(rq2->lock)
+{
+        spin_unlock(&rq1->lock);
+        if (rq1 != rq2)
+                spin_unlock(&rq2->lock);
+        else
+                __release(rq2->lock);
+}
+
+/*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+static void double_lock_balance(runqueue_t *this_rq, runqueue_t *busiest)
+        __releases(this_rq->lock)
+        __acquires(busiest->lock)
+        __acquires(this_rq->lock)
+{
+        if (unlikely(!spin_trylock(&busiest->lock))) {
+                if (busiest < this_rq) {
+                        spin_unlock(&this_rq->lock);
+                        spin_lock(&busiest->lock);
+                        spin_lock(&this_rq->lock);
+                } else
+                        spin_lock(&busiest->lock);
+        }
+}
+
+/*
+ * find_idlest_cpu - find the least busy runqueue.
+ */
+static int find_idlest_cpu(struct task_struct *p, int this_cpu,
+                           struct sched_domain *sd)
+{
+        unsigned long load, min_load, this_load;
+        int i, min_cpu;
+        cpumask_t mask;
+
+        min_cpu = UINT_MAX;
+        min_load = ULONG_MAX;
+
+        cpus_and(mask, sd->span, p->cpus_allowed);
+
+        for_each_cpu_mask(i, mask) {
+                load = target_load(i);
+
+                if (load < min_load) {
+                        min_cpu = i;
+                        min_load = load;
+
+                        /* break out early on an idle CPU: */
+                        if (!min_load)
+                                break;
+                }
+        }
+
+        /* add +1 to account for the new task */
+        this_load = source_load(this_cpu) + SCHED_LOAD_SCALE;
+
+        /*
+         * Would with the addition of the new task to the
+         * current CPU there be an imbalance between this
+         * CPU and the idlest CPU?
+         *
+         * Use half of the balancing threshold - new-context is
+         * a good opportunity to balance.
+         */
+        if (min_load*(100 + (sd->imbalance_pct-100)/2) < this_load*100)
+                return min_cpu;
+
+        return this_cpu;
+}
+
+/*
+ * If dest_cpu is allowed for this process, migrate the task to it.
+ * This is accomplished by forcing the cpu_allowed mask to only
+ * allow dest_cpu, which will force the cpu onto dest_cpu.  Then
+ * the cpu_allowed mask is restored.
+ */
+static void sched_migrate_task(task_t *p, int dest_cpu)
+{
+        migration_req_t req;
+        runqueue_t *rq;
+        unsigned long flags;
+
+        rq = task_rq_lock(p, &flags);
+        if (!cpu_isset(dest_cpu, p->cpus_allowed)
+            || unlikely(cpu_is_offline(dest_cpu)))
+                goto out;
+
+        /* force the process onto the specified CPU */
+        if (migrate_task(p, dest_cpu, &req)) {
+                /* Need to wait for migration thread (might exit: take ref). */
+                struct task_struct *mt = rq->migration_thread;
+                get_task_struct(mt);
+                task_rq_unlock(rq, &flags);
+                wake_up_process(mt);
+                put_task_struct(mt);
+                wait_for_completion(&req.done);
+                return;
+        }
+out:
+        task_rq_unlock(rq, &flags);
+}
+
+/*
+ * sched_exec(): find the highest-level, exec-balance-capable
+ * domain and try to migrate the task to the least loaded CPU.
+ *
+ * execve() is a valuable balancing opportunity, because at this point
+ * the task has the smallest effective memory and cache footprint.
+ */
+void sched_exec(void)
+{
+        struct sched_domain *tmp, *sd = NULL;
+        int new_cpu, this_cpu = get_cpu();
+
+        /* Prefer the current CPU if there's only this task running */
+        if (this_rq()->nr_running <= 1)
+                goto out;
+
+        for_each_domain(this_cpu, tmp)
+                if (tmp->flags & SD_BALANCE_EXEC)
+                        sd = tmp;
+
+        if (sd) {
+                schedstat_inc(sd, sbe_attempts);
+                new_cpu = find_idlest_cpu(current, this_cpu, sd);
+                if (new_cpu != this_cpu) {
+                        schedstat_inc(sd, sbe_pushed);
+                        put_cpu();
+                        sched_migrate_task(current, new_cpu);
+                        return;
+                }
+        }
+out:
+        put_cpu();
+}
+
+/*
+ * pull_task - move a task from a remote runqueue to the local runqueue.
+ * Both runqueues must be locked.
+ */
+static inline
+void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p,
+               runqueue_t *this_rq, prio_array_t *this_array, int this_cpu)
+{
+        dequeue_task(p, src_array);
+        src_rq->nr_running--;
+        set_task_cpu(p, this_cpu);
+        this_rq->nr_running++;
+        enqueue_task(p, this_array);
+        p->timestamp = (p->timestamp - src_rq->timestamp_last_tick)
+                                + this_rq->timestamp_last_tick;
+        /*
+         * Note that idle threads have a prio of MAX_PRIO, for this test
+         * to be always true for them.
+         */
+        if (TASK_PREEMPTS_CURR(p, this_rq))
+                resched_task(this_rq->curr);
+}
+
+/*
+ * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
+ */
+static inline
+int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu,
+                     struct sched_domain *sd, enum idle_type idle)
+{
+        /*
+         * We do not migrate tasks that are:
+         * 1) running (obviously), or
+         * 2) cannot be migrated to this CPU due to cpus_allowed, or
+         * 3) are cache-hot on their current CPU.
+         */
+        if (task_running(rq, p))
+                return 0;
+        if (!cpu_isset(this_cpu, p->cpus_allowed))
+                return 0;
+
+        /*
+         * Aggressive migration if:
+         * 1) the [whole] cpu is idle, or
+         * 2) too many balance attempts have failed.
+         */
+
+        if (cpu_and_siblings_are_idle(this_cpu) || \
+                        sd->nr_balance_failed > sd->cache_nice_tries)
+                return 1;
+
+        if (task_hot(p, rq->timestamp_last_tick, sd))
+                        return 0;
+        return 1;
+}
+
+/*
+ * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq,
+ * as part of a balancing operation within "domain". Returns the number of
+ * tasks moved.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest,
+                      unsigned long max_nr_move, struct sched_domain *sd,
+                      enum idle_type idle)
+{
+        prio_array_t *array, *dst_array;
+        struct list_head *head, *curr;
+        int idx, pulled = 0;
+        task_t *tmp;
+
+        if (max_nr_move <= 0 || busiest->nr_running <= 1)
+                goto out;
+
+        /*
+         * We first consider expired tasks. Those will likely not be
+         * executed in the near future, and they are most likely to
+         * be cache-cold, thus switching CPUs has the least effect
+         * on them.
+         */
+        if (busiest->expired->nr_active) {
+                array = busiest->expired;
+                dst_array = this_rq->expired;
+        } else {
+                array = busiest->active;
+                dst_array = this_rq->active;
+        }
+
+new_array:
+        /* Start searching at priority 0: */
+        idx = 0;
+skip_bitmap:
+        if (!idx)
+                idx = sched_find_first_bit(array->bitmap);
+        else
+                idx = find_next_bit(array->bitmap, MAX_PRIO, idx);
+        if (idx >= MAX_PRIO) {
+                if (array == busiest->expired && busiest->active->nr_active) {
+                        array = busiest->active;
+                        dst_array = this_rq->active;
+                        goto new_array;
+                }
+                goto out;
+        }
+
+        head = array->queue + idx;
+        curr = head->prev;
+skip_queue:
+        tmp = list_entry(curr, task_t, run_list);
+
+        curr = curr->prev;
+
+        if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle)) {
+                if (curr != head)
+                        goto skip_queue;
+                idx++;
+                goto skip_bitmap;
+        }
+
+#ifdef CONFIG_SCHEDSTATS
+        if (task_hot(tmp, busiest->timestamp_last_tick, sd))
+                schedstat_inc(sd, lb_hot_gained[idle]);
+#endif
+
+        pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
+        pulled++;
+
+        /* We only want to steal up to the prescribed number of tasks. */
+        if (pulled < max_nr_move) {
+                if (curr != head)
+                        goto skip_queue;
+                idx++;
+                goto skip_bitmap;
+        }
+out:
+        /*
+         * Right now, this is the only place pull_task() is called,
+         * so we can safely collect pull_task() stats here rather than
+         * inside pull_task().
+         */
+        schedstat_add(sd, lb_gained[idle], pulled);
+        return pulled;
+}
+
+/*
+ * find_busiest_group finds and returns the busiest CPU group within the
+ * domain. It calculates and returns the number of tasks which should be
+ * moved to restore balance via the imbalance parameter.
+ */
+static struct sched_group *
+find_busiest_group(struct sched_domain *sd, int this_cpu,
+                   unsigned long *imbalance, enum idle_type idle)
+{
+        struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
+        unsigned long max_load, avg_load, total_load, this_load, total_pwr;
+
+        max_load = this_load = total_load = total_pwr = 0;
+
+        do {
+                unsigned long load;
+                int local_group;
+                int i;
+
+                local_group = cpu_isset(this_cpu, group->cpumask);
+
+                /* Tally up the load of all CPUs in the group */
+                avg_load = 0;
+
+                for_each_cpu_mask(i, group->cpumask) {
+                        /* Bias balancing toward cpus of our domain */
+                        if (local_group)
+                                load = target_load(i);
+                        else
+                                load = source_load(i);
+
+                        avg_load += load;
+                }
+
+                total_load += avg_load;
+                total_pwr += group->cpu_power;
+
+                /* Adjust by relative CPU power of the group */
+                avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
+
+                if (local_group) {
+                        this_load = avg_load;
+                        this = group;
+                        goto nextgroup;
+                } else if (avg_load > max_load) {
+                        max_load = avg_load;
+                        busiest = group;
+                }
+nextgroup:
+                group = group->next;
+        } while (group != sd->groups);
+
+        if (!busiest || this_load >= max_load)
+                goto out_balanced;
+
+        avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
+
+        if (this_load >= avg_load ||
+                        100*max_load <= sd->imbalance_pct*this_load)
+                goto out_balanced;
+
+        /*
+         * We're trying to get all the cpus to the average_load, so we don't
+         * want to push ourselves above the average load, nor do we wish to
+         * reduce the max loaded cpu below the average load, as either of these
+         * actions would just result in more rebalancing later, and ping-pong
+         * tasks around. Thus we look for the minimum possible imbalance.
+         * Negative imbalances (*we* are more loaded than anyone else) will
+         * be counted as no imbalance for these purposes -- we can't fix that
+         * by pulling tasks to us.  Be careful of negative numbers as they'll
+         * appear as very large values with unsigned longs.
+         */
+        /* How much load to actually move to equalise the imbalance */
+        *imbalance = min((max_load - avg_load) * busiest->cpu_power,
+                                (avg_load - this_load) * this->cpu_power)
+                        / SCHED_LOAD_SCALE;
+
+        if (*imbalance < SCHED_LOAD_SCALE) {
+                unsigned long pwr_now = 0, pwr_move = 0;
+                unsigned long tmp;
+
+                if (max_load - this_load >= SCHED_LOAD_SCALE*2) {
+                        *imbalance = 1;
+                        return busiest;
+                }
+
+                /*
+                 * OK, we don't have enough imbalance to justify moving tasks,
+                 * however we may be able to increase total CPU power used by
+                 * moving them.
+                 */
+
+                pwr_now += busiest->cpu_power*min(SCHED_LOAD_SCALE, max_load);
+                pwr_now += this->cpu_power*min(SCHED_LOAD_SCALE, this_load);
+                pwr_now /= SCHED_LOAD_SCALE;
+
+                /* Amount of load we'd subtract */
+                tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/busiest->cpu_power;
+                if (max_load > tmp)
+                        pwr_move += busiest->cpu_power*min(SCHED_LOAD_SCALE,
+                                                        max_load - tmp);
+
+                /* Amount of load we'd add */
+                if (max_load*busiest->cpu_power <
+                                SCHED_LOAD_SCALE*SCHED_LOAD_SCALE)
+                        tmp = max_load*busiest->cpu_power/this->cpu_power;
+                else
+                        tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power;
+                pwr_move += this->cpu_power*min(SCHED_LOAD_SCALE, this_load + tmp);
+                pwr_move /= SCHED_LOAD_SCALE;
+
+                /* Move if we gain throughput */
+                if (pwr_move <= pwr_now)
+                        goto out_balanced;
+
+                *imbalance = 1;
+                return busiest;
+        }
+
+        /* Get rid of the scaling factor, rounding down as we divide */
+        *imbalance = *imbalance / SCHED_LOAD_SCALE;
+
+        return busiest;
+
+out_balanced:
+        if (busiest && (idle == NEWLY_IDLE ||
+                        (idle == SCHED_IDLE && max_load > SCHED_LOAD_SCALE)) ) {
+                *imbalance = 1;
+                return busiest;
+        }
+
+        *imbalance = 0;
+        return NULL;
+}
+
+/*
+ * find_busiest_queue - find the busiest runqueue among the cpus in group.
+ */
+static runqueue_t *find_busiest_queue(struct sched_group *group)
+{
+        unsigned long load, max_load = 0;
+        runqueue_t *busiest = NULL;
+        int i;
+
+        for_each_cpu_mask(i, group->cpumask) {
+                load = source_load(i);
+
+                if (load > max_load) {
+                        max_load = load;
+                        busiest = cpu_rq(i);
+                }
+        }
+
+        return busiest;
+}
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ *
+ * Called with this_rq unlocked.
+ */
+static int load_balance(int this_cpu, runqueue_t *this_rq,
+                        struct sched_domain *sd, enum idle_type idle)
+{
+        struct sched_group *group;
+        runqueue_t *busiest;
+        unsigned long imbalance;
+        int nr_moved;
+
+        spin_lock(&this_rq->lock);
+        schedstat_inc(sd, lb_cnt[idle]);
+
+        group = find_busiest_group(sd, this_cpu, &imbalance, idle);
+        if (!group) {
+                schedstat_inc(sd, lb_nobusyg[idle]);
+                goto out_balanced;
+        }
+
+        busiest = find_busiest_queue(group);
+        if (!busiest) {
+                schedstat_inc(sd, lb_nobusyq[idle]);
+                goto out_balanced;
+        }
+
+        /*
+         * This should be "impossible", but since load
+         * balancing is inherently racy and statistical,
+         * it could happen in theory.
+         */
+        if (unlikely(busiest == this_rq)) {
+                WARN_ON(1);
+                goto out_balanced;
+        }
+
+        schedstat_add(sd, lb_imbalance[idle], imbalance);
+
+        nr_moved = 0;
+        if (busiest->nr_running > 1) {
+                /*
+                 * Attempt to move tasks. If find_busiest_group has found
+                 * an imbalance but busiest->nr_running <= 1, the group is
+                 * still unbalanced. nr_moved simply stays zero, so it is
+                 * correctly treated as an imbalance.
+                 */
+                double_lock_balance(this_rq, busiest);
+                nr_moved = move_tasks(this_rq, this_cpu, busiest,
+                                                imbalance, sd, idle);
+                spin_unlock(&busiest->lock);
+        }
+        spin_unlock(&this_rq->lock);
+
+        if (!nr_moved) {
+                schedstat_inc(sd, lb_failed[idle]);
+                sd->nr_balance_failed++;
+
+                if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
+                        int wake = 0;
+
+                        spin_lock(&busiest->lock);
+                        if (!busiest->active_balance) {
+                                busiest->active_balance = 1;
+                                busiest->push_cpu = this_cpu;
+                                wake = 1;
+                        }
+                        spin_unlock(&busiest->lock);
+                        if (wake)
+                                wake_up_process(busiest->migration_thread);
+
+                        /*
+                         * We've kicked active balancing, reset the failure
+                         * counter.
+                         */
+                        sd->nr_balance_failed = sd->cache_nice_tries;
+                }
+
+                /*
+                 * We were unbalanced, but unsuccessful in move_tasks(),
+                 * so bump the balance_interval to lessen the lock contention.
+                 */
+                if (sd->balance_interval < sd->max_interval)
+                        sd->balance_interval++;
+        } else {
+                sd->nr_balance_failed = 0;
+
+                /* We were unbalanced, so reset the balancing interval */
+                sd->balance_interval = sd->min_interval;
+        }
+
+        return nr_moved;
+
+out_balanced:
+        spin_unlock(&this_rq->lock);
+
+        schedstat_inc(sd, lb_balanced[idle]);
+
+        /* tune up the balancing interval */
+        if (sd->balance_interval < sd->max_interval)
+                sd->balance_interval *= 2;
+
+        return 0;
+}
+
+/*
+ * Check this_cpu to ensure it is balanced within domain. Attempt to move
+ * tasks if there is an imbalance.
+ *
+ * Called from schedule when this_rq is about to become idle (NEWLY_IDLE).
+ * this_rq is locked.
+ */
+static int load_balance_newidle(int this_cpu, runqueue_t *this_rq,
+                                struct sched_domain *sd)
+{
+        struct sched_group *group;
+        runqueue_t *busiest = NULL;
+        unsigned long imbalance;
+        int nr_moved = 0;
+
+        schedstat_inc(sd, lb_cnt[NEWLY_IDLE]);
+        group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE);
+        if (!group) {
+                schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
+                schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]);
+                goto out;
+        }
+
+        busiest = find_busiest_queue(group);
+        if (!busiest || busiest == this_rq) {
+                schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
+                schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
+                goto out;
+        }
+
+        /* Attempt to move tasks */
+        double_lock_balance(this_rq, busiest);
+
+        schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance);
+        nr_moved = move_tasks(this_rq, this_cpu, busiest,
+                                        imbalance, sd, NEWLY_IDLE);
+        if (!nr_moved)
+                schedstat_inc(sd, lb_failed[NEWLY_IDLE]);
+
+        spin_unlock(&busiest->lock);
+
+out:
+        return nr_moved;
+}
+
+/*
+ * idle_balance is called by schedule() if this_cpu is about to become
+ * idle. Attempts to pull tasks from other CPUs.
+ */
+static inline void idle_balance(int this_cpu, runqueue_t *this_rq)
+{
+        struct sched_domain *sd;
+
+        for_each_domain(this_cpu, sd) {
+                if (sd->flags & SD_BALANCE_NEWIDLE) {
+                        if (load_balance_newidle(this_cpu, this_rq, sd)) {
+                                /* We've pulled tasks over so stop searching */
+                                break;
+                        }
+                }
+        }
+}
+
+/*
+ * active_load_balance is run by migration threads. It pushes running tasks
+ * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
+ * running on each physical CPU where possible, and avoids physical /
+ * logical imbalances.
+ *
+ * Called with busiest_rq locked.
+ */
+static void active_load_balance(runqueue_t *busiest_rq, int busiest_cpu)
+{
+        struct sched_domain *sd;
+        struct sched_group *cpu_group;
+        runqueue_t *target_rq;
+        cpumask_t visited_cpus;
+        int cpu;
+
+        /*
+         * Search for suitable CPUs to push tasks to in successively higher
+         * domains with SD_LOAD_BALANCE set.
+         */
+        visited_cpus = CPU_MASK_NONE;
+        for_each_domain(busiest_cpu, sd) {
+                if (!(sd->flags & SD_LOAD_BALANCE))
+                        /* no more domains to search */
+                        break;
+
+                schedstat_inc(sd, alb_cnt);
+
+                cpu_group = sd->groups;
+                do {
+                        for_each_cpu_mask(cpu, cpu_group->cpumask) {
+                                if (busiest_rq->nr_running <= 1)
+                                        /* no more tasks left to move */
+                                        return;
+                                if (cpu_isset(cpu, visited_cpus))
+                                        continue;
+                                cpu_set(cpu, visited_cpus);
+                                if (!cpu_and_siblings_are_idle(cpu) || cpu == busiest_cpu)
+                                        continue;
+
+                                target_rq = cpu_rq(cpu);
+                                /*
+                                 * This condition is "impossible", if it occurs
+                                 * we need to fix it.  Originally reported by
+                                 * Bjorn Helgaas on a 128-cpu setup.
+                                 */
+                                BUG_ON(busiest_rq == target_rq);
+
+                                /* move a task from busiest_rq to target_rq */
+                                double_lock_balance(busiest_rq, target_rq);
+                                if (move_tasks(target_rq, cpu, busiest_rq,
+                                                1, sd, SCHED_IDLE)) {
+                                        schedstat_inc(sd, alb_pushed);
+                                } else {
+                                        schedstat_inc(sd, alb_failed);
+                                }
+                                spin_unlock(&target_rq->lock);
+                        }
+                        cpu_group = cpu_group->next;
+                } while (cpu_group != sd->groups);
+        }
+}
+
+/*
+ * rebalance_tick will get called every timer tick, on every CPU.
+ *
+ * It checks each scheduling domain to see if it is due to be balanced,
+ * and initiates a balancing operation if so.
+ *
+ * Balancing parameters are set up in arch_init_sched_domains.
+ */
+
+/* Don't have all balancing operations going off at once */
+#define CPU_OFFSET(cpu) (HZ * cpu / NR_CPUS)
+
+static void rebalance_tick(int this_cpu, runqueue_t *this_rq,
+                           enum idle_type idle)
+{
+        unsigned long old_load, this_load;
+        unsigned long j = jiffies + CPU_OFFSET(this_cpu);
+        struct sched_domain *sd;
+
+        /* Update our load */
+        old_load = this_rq->cpu_load;
+        this_load = this_rq->nr_running * SCHED_LOAD_SCALE;
+        /*
+         * Round up the averaging division if load is increasing. This
+         * prevents us from getting stuck on 9 if the load is 10, for
+         * example.
+         */
+        if (this_load > old_load)
+                old_load++;
+        this_rq->cpu_load = (old_load + this_load) / 2;
+
+        for_each_domain(this_cpu, sd) {
+                unsigned long interval;
+
+                if (!(sd->flags & SD_LOAD_BALANCE))
+                        continue;
+
+                interval = sd->balance_interval;
+                if (idle != SCHED_IDLE)
+                        interval *= sd->busy_factor;
+
+                /* scale ms to jiffies */
+                interval = msecs_to_jiffies(interval);
+                if (unlikely(!interval))
+                        interval = 1;
+
+                if (j - sd->last_balance >= interval) {
+                        if (load_balance(this_cpu, this_rq, sd, idle)) {
+                                /* We've pulled tasks over so no longer idle */
+                                idle = NOT_IDLE;
+                        }
+                        sd->last_balance += interval;
+                }
+        }
+}
+#else
+/*
+ * on UP we do not need to balance between CPUs:
+ */
+static inline void rebalance_tick(int cpu, runqueue_t *rq, enum idle_type idle)
+{
+}
+static inline void idle_balance(int cpu, runqueue_t *rq)
+{
+}
+#endif
+
+static inline int wake_priority_sleeper(runqueue_t *rq)
+{
+        int ret = 0;
+#ifdef CONFIG_SCHED_SMT
+        spin_lock(&rq->lock);
+        /*
+         * If an SMT sibling task has been put to sleep for priority
+         * reasons reschedule the idle task to see if it can now run.
+         */
+        if (rq->nr_running) {
+                resched_task(rq->idle);
+                ret = 1;
+        }
+        spin_unlock(&rq->lock);
+#endif
+        return ret;
+}
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+
+/*
+ * This is called on clock ticks and on context switches.
+ * Bank in p->sched_time the ns elapsed since the last tick or switch.
+ */
+static inline void update_cpu_clock(task_t *p, runqueue_t *rq,
+                                    unsigned long long now)
+{
+        unsigned long long last = max(p->timestamp, rq->timestamp_last_tick);
+        p->sched_time += now - last;
+}
+
+/*
+ * Return current->sched_time plus any more ns on the sched_clock
+ * that have not yet been banked.
+ */
+unsigned long long current_sched_time(const task_t *tsk)
+{
+        unsigned long long ns;
+        unsigned long flags;
+        local_irq_save(flags);
+        ns = max(tsk->timestamp, task_rq(tsk)->timestamp_last_tick);
+        ns = tsk->sched_time + (sched_clock() - ns);
+        local_irq_restore(flags);
+        return ns;
+}
+
+/*
+ * We place interactive tasks back into the active array, if possible.
+ *
+ * To guarantee that this does not starve expired tasks we ignore the
+ * interactivity of a task if the first expired task had to wait more
+ * than a 'reasonable' amount of time. This deadline timeout is
+ * load-dependent, as the frequency of array switched decreases with
+ * increasing number of running tasks. We also ignore the interactivity
+ * if a better static_prio task has expired:
+ */
+#define EXPIRED_STARVING(rq) \
+        ((STARVATION_LIMIT && ((rq)->expired_timestamp && \
+                (jiffies - (rq)->expired_timestamp >= \
+                        STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \
+                        ((rq)->curr->static_prio > (rq)->best_expired_prio))
+
+/*
+ * Account user 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 user space since the last update
+ */
+void account_user_time(struct task_struct *p, cputime_t cputime)
+{
+        struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+        cputime64_t tmp;
+
+        p->utime = cputime_add(p->utime, cputime);
+
+        /* Add user time to cpustat. */
+        tmp = cputime_to_cputime64(cputime);
+        if (TASK_NICE(p) > 0)
+                cpustat->nice = cputime64_add(cpustat->nice, tmp);
+        else
+                cpustat->user = cputime64_add(cpustat->user, tmp);
+}
+
+/*
+ * 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
+ */
+void account_system_time(struct task_struct *p, int hardirq_offset,
+                         cputime_t cputime)
+{
+        struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+        runqueue_t *rq = this_rq();
+        cputime64_t tmp;
+
+        p->stime = cputime_add(p->stime, cputime);
+
+        /* Add system time to cpustat. */
+        tmp = cputime_to_cputime64(cputime);
+        if (hardirq_count() - hardirq_offset)
+                cpustat->irq = cputime64_add(cpustat->irq, tmp);
+        else if (softirq_count())
+                cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
+        else if (p != rq->idle)
+                cpustat->system = cputime64_add(cpustat->system, tmp);
+        else if (atomic_read(&rq->nr_iowait) > 0)
+                cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
+        else
+                cpustat->idle = cputime64_add(cpustat->idle, tmp);
+        /* Account for system time used */
+        acct_update_integrals(p);
+        /* Update rss highwater mark */
+        update_mem_hiwater(p);
+}
+
+/*
+ * Account for involuntary wait time.
+ * @p: the process from which the cpu time has been stolen
+ * @steal: the cpu time spent in involuntary wait
+ */
+void account_steal_time(struct task_struct *p, cputime_t steal)
+{
+        struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+        cputime64_t tmp = cputime_to_cputime64(steal);
+        runqueue_t *rq = this_rq();
+
+        if (p == rq->idle) {
+                p->stime = cputime_add(p->stime, steal);
+                if (atomic_read(&rq->nr_iowait) > 0)
+                        cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
+                else
+                        cpustat->idle = cputime64_add(cpustat->idle, tmp);
+        } else
+                cpustat->steal = cputime64_add(cpustat->steal, tmp);
+}
+
+/*
+ * This function gets called by the timer code, with HZ frequency.
+ * We call it with interrupts disabled.
+ *
+ * It also gets called by the fork code, when changing the parent's
+ * timeslices.
+ */
+void scheduler_tick(void)
+{
+        int cpu = smp_processor_id();
+        runqueue_t *rq = this_rq();
+        task_t *p = current;
+        unsigned long long now = sched_clock();
+
+        update_cpu_clock(p, rq, now);
+
+        rq->timestamp_last_tick = now;
+
+        if (p == rq->idle) {
+                if (wake_priority_sleeper(rq))
+                        goto out;
+                rebalance_tick(cpu, rq, SCHED_IDLE);
+                return;
+        }
+
+        /* Task might have expired already, but not scheduled off yet */
+        if (p->array != rq->active) {
+                set_tsk_need_resched(p);
+                goto out;
+        }
+        spin_lock(&rq->lock);
+        /*
+         * The task was running during this tick - update the
+         * time slice counter. Note: we do not update a thread's
+         * priority until it either goes to sleep or uses up its
+         * timeslice. This makes it possible for interactive tasks
+         * to use up their timeslices at their highest priority levels.
+         */
+        if (rt_task(p)) {
+                /*
+                 * RR tasks need a special form of timeslice management.
+                 * FIFO tasks have no timeslices.
+                 */
+                if ((p->policy == SCHED_RR) && !--p->time_slice) {
+                        p->time_slice = task_timeslice(p);
+                        p->first_time_slice = 0;
+                        set_tsk_need_resched(p);
+
+                        /* put it at the end of the queue: */
+                        requeue_task(p, rq->active);
+                }
+                goto out_unlock;
+        }
+        if (!--p->time_slice) {
+                dequeue_task(p, rq->active);
+                set_tsk_need_resched(p);
+                p->prio = effective_prio(p);
+                p->time_slice = task_timeslice(p);
+                p->first_time_slice = 0;
+
+                if (!rq->expired_timestamp)
+                        rq->expired_timestamp = jiffies;
+                if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) {
+                        enqueue_task(p, rq->expired);
+                        if (p->static_prio < rq->best_expired_prio)
+                                rq->best_expired_prio = p->static_prio;
+                } else
+                        enqueue_task(p, rq->active);
+        } else {
+                /*
+                 * Prevent a too long timeslice allowing a task to monopolize
+                 * the CPU. We do this by splitting up the timeslice into
+                 * smaller pieces.
+                 *
+                 * Note: this does not mean the task's timeslices expire or
+                 * get lost in any way, they just might be preempted by
+                 * another task of equal priority. (one with higher
+                 * priority would have preempted this task already.) We
+                 * requeue this task to the end of the list on this priority
+                 * level, which is in essence a round-robin of tasks with
+                 * equal priority.
+                 *
+                 * This only applies to tasks in the interactive
+                 * delta range with at least TIMESLICE_GRANULARITY to requeue.
+                 */
+                if (TASK_INTERACTIVE(p) && !((task_timeslice(p) -
+                        p->time_slice) % TIMESLICE_GRANULARITY(p)) &&
+                        (p->time_slice >= TIMESLICE_GRANULARITY(p)) &&
+                        (p->array == rq->active)) {
+
+                        requeue_task(p, rq->active);
+                        set_tsk_need_resched(p);
+                }
+        }
+out_unlock:
+        spin_unlock(&rq->lock);
+out:
+        rebalance_tick(cpu, rq, NOT_IDLE);
+}
+
+#ifdef CONFIG_SCHED_SMT
+static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq)
+{
+        struct sched_domain *sd = this_rq->sd;
+        cpumask_t sibling_map;
+        int i;
+
+        if (!(sd->flags & SD_SHARE_CPUPOWER))
+                return;
+
+        /*
+         * Unlock the current runqueue because we have to lock in
+         * CPU order to avoid deadlocks. Caller knows that we might
+         * unlock. We keep IRQs disabled.
+         */
+        spin_unlock(&this_rq->lock);
+
+        sibling_map = sd->span;
+
+        for_each_cpu_mask(i, sibling_map)
+                spin_lock(&cpu_rq(i)->lock);
+        /*
+         * We clear this CPU from the mask. This both simplifies the
+         * inner loop and keps this_rq locked when we exit:
+         */
+        cpu_clear(this_cpu, sibling_map);
+
+        for_each_cpu_mask(i, sibling_map) {
+                runqueue_t *smt_rq = cpu_rq(i);
+
+                /*
+                 * If an SMT sibling task is sleeping due to priority
+                 * reasons wake it up now.
+                 */
+                if (smt_rq->curr == smt_rq->idle && smt_rq->nr_running)
+                        resched_task(smt_rq->idle);
+        }
+
+        for_each_cpu_mask(i, sibling_map)
+                spin_unlock(&cpu_rq(i)->lock);
+        /*
+         * We exit with this_cpu's rq still held and IRQs
+         * still disabled:
+         */
+}
+
+static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq)
+{
+        struct sched_domain *sd = this_rq->sd;
+        cpumask_t sibling_map;
+        prio_array_t *array;
+        int ret = 0, i;
+        task_t *p;
+
+        if (!(sd->flags & SD_SHARE_CPUPOWER))
+                return 0;
+
+        /*
+         * The same locking rules and details apply as for
+         * wake_sleeping_dependent():
+         */
+        spin_unlock(&this_rq->lock);
+        sibling_map = sd->span;
+        for_each_cpu_mask(i, sibling_map)
+                spin_lock(&cpu_rq(i)->lock);
+        cpu_clear(this_cpu, sibling_map);
+
+        /*
+         * Establish next task to be run - it might have gone away because
+         * we released the runqueue lock above:
+         */
+        if (!this_rq->nr_running)
+                goto out_unlock;
+        array = this_rq->active;
+        if (!array->nr_active)
+                array = this_rq->expired;
+        BUG_ON(!array->nr_active);
+
+        p = list_entry(array->queue[sched_find_first_bit(array->bitmap)].next,
+                task_t, run_list);
+
+        for_each_cpu_mask(i, sibling_map) {
+                runqueue_t *smt_rq = cpu_rq(i);
+                task_t *smt_curr = smt_rq->curr;
+
+                /*
+                 * If a user task with lower static priority than the
+                 * running task on the SMT sibling is trying to schedule,
+                 * delay it till there is proportionately less timeslice
+                 * left of the sibling task to prevent a lower priority
+                 * task from using an unfair proportion of the
+                 * physical cpu's resources. -ck
+                 */
+                if (((smt_curr->time_slice * (100 - sd->per_cpu_gain) / 100) >
+                        task_timeslice(p) || rt_task(smt_curr)) &&
+                        p->mm && smt_curr->mm && !rt_task(p))
+                                ret = 1;
+
+                /*
+                 * Reschedule a lower priority task on the SMT sibling,
+                 * or wake it up if it has been put to sleep for priority
+                 * reasons.
+                 */
+                if ((((p->time_slice * (100 - sd->per_cpu_gain) / 100) >
+                        task_timeslice(smt_curr) || rt_task(p)) &&
+                        smt_curr->mm && p->mm && !rt_task(smt_curr)) ||
+                        (smt_curr == smt_rq->idle && smt_rq->nr_running))
+                                resched_task(smt_curr);
+        }
+out_unlock:
+        for_each_cpu_mask(i, sibling_map)
+                spin_unlock(&cpu_rq(i)->lock);
+        return ret;
+}
+#else
+static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq)
+{
+}
+
+static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq)
+{
+        return 0;
+}
+#endif
+
+#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
+
+void fastcall add_preempt_count(int val)
+{
+        /*
+         * Underflow?
+         */
+        BUG_ON(((int)preempt_count() < 0));
+        preempt_count() += val;
+        /*
+         * Spinlock count overflowing soon?
+         */
+        BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
+}
+EXPORT_SYMBOL(add_preempt_count);
+
+void fastcall sub_preempt_count(int val)
+{
+        /*
+         * Underflow?
+         */
+        BUG_ON(val > preempt_count());
+        /*
+         * Is the spinlock portion underflowing?
+         */
+        BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
+        preempt_count() -= val;
+}
+EXPORT_SYMBOL(sub_preempt_count);
+
+#endif
+
+/*
+ * schedule() is the main scheduler function.
+ */
+asmlinkage void __sched schedule(void)
+{
+        long *switch_count;
+        task_t *prev, *next;
+        runqueue_t *rq;
+        prio_array_t *array;
+        struct list_head *queue;
+        unsigned long long now;
+        unsigned long run_time;
+        int cpu, idx;
+
+        /*
+         * Test if we are atomic.  Since do_exit() needs to call into
+         * schedule() atomically, we ignore that path for now.
+         * Otherwise, whine if we are scheduling when we should not be.
+         */
+        if (likely(!current->exit_state)) {
+                if (unlikely(in_atomic())) {
+                        printk(KERN_ERR "scheduling while atomic: "
+                                "%s/0x%08x/%d\n",
+                                current->comm, preempt_count(), current->pid);
+                        dump_stack();
+                }
+        }
+        profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+need_resched:
+        preempt_disable();
+        prev = current;
+        release_kernel_lock(prev);
+need_resched_nonpreemptible:
+        rq = this_rq();
+
+        /*
+         * The idle thread is not allowed to schedule!
+         * Remove this check after it has been exercised a bit.
+         */
+        if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) {
+                printk(KERN_ERR "bad: scheduling from the idle thread!\n");
+                dump_stack();
+        }
+
+        schedstat_inc(rq, sched_cnt);
+        now = sched_clock();
+        if (likely((long long)now - prev->timestamp < NS_MAX_SLEEP_AVG)) {
+                run_time = now - prev->timestamp;
+                if (unlikely((long long)now - prev->timestamp < 0))
+                        run_time = 0;
+        } else
+                run_time = NS_MAX_SLEEP_AVG;
+
+        /*
+         * Tasks charged proportionately less run_time at high sleep_avg to
+         * delay them losing their interactive status
+         */
+        run_time /= (CURRENT_BONUS(prev) ? : 1);
+
+        spin_lock_irq(&rq->lock);
+
+        if (unlikely(prev->flags & PF_DEAD))
+                prev->state = EXIT_DEAD;
+
+        switch_count = &prev->nivcsw;
+        if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+                switch_count = &prev->nvcsw;
+                if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
+                                unlikely(signal_pending(prev))))
+                        prev->state = TASK_RUNNING;
+                else {
+                        if (prev->state == TASK_UNINTERRUPTIBLE)
+                                rq->nr_uninterruptible++;
+                        deactivate_task(prev, rq);
+                }
+        }
+
+        cpu = smp_processor_id();
+        if (unlikely(!rq->nr_running)) {
+go_idle:
+                idle_balance(cpu, rq);
+                if (!rq->nr_running) {
+                        next = rq->idle;
+                        rq->expired_timestamp = 0;
+                        wake_sleeping_dependent(cpu, rq);
+                        /*
+                         * wake_sleeping_dependent() might have released
+                         * the runqueue, so break out if we got new
+                         * tasks meanwhile:
+                         */
+                        if (!rq->nr_running)
+                                goto switch_tasks;
+                }
+        } else {
+                if (dependent_sleeper(cpu, rq)) {
+                        next = rq->idle;
+                        goto switch_tasks;
+                }
+                /*
+                 * dependent_sleeper() releases and reacquires the runqueue
+                 * lock, hence go into the idle loop if the rq went
+                 * empty meanwhile:
+                 */
+                if (unlikely(!rq->nr_running))
+                        goto go_idle;
+        }
+
+        array = rq->active;
+        if (unlikely(!array->nr_active)) {
+                /*
+                 * Switch the active and expired arrays.
+                 */
+                schedstat_inc(rq, sched_switch);
+                rq->active = rq->expired;
+                rq->expired = array;
+                array = rq->active;
+                rq->expired_timestamp = 0;
+                rq->best_expired_prio = MAX_PRIO;
+        }
+
+        idx = sched_find_first_bit(array->bitmap);
+        queue = array->queue + idx;
+        next = list_entry(queue->next, task_t, run_list);
+
+        if (!rt_task(next) && next->activated > 0) {
+                unsigned long long delta = now - next->timestamp;
+                if (unlikely((long long)now - next->timestamp < 0))
+                        delta = 0;
+
+                if (next->activated == 1)
+                        delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
+
+                array = next->array;
+                dequeue_task(next, array);
+                recalc_task_prio(next, next->timestamp + delta);
+                enqueue_task(next, array);
+        }
+        next->activated = 0;
+switch_tasks:
+        if (next == rq->idle)
+                schedstat_inc(rq, sched_goidle);
+        prefetch(next);
+        clear_tsk_need_resched(prev);
+        rcu_qsctr_inc(task_cpu(prev));
+
+        update_cpu_clock(prev, rq, now);
+
+        prev->sleep_avg -= run_time;
+        if ((long)prev->sleep_avg <= 0)
+                prev->sleep_avg = 0;
+        prev->timestamp = prev->last_ran = now;
+
+        sched_info_switch(prev, next);
+        if (likely(prev != next)) {
+                next->timestamp = now;
+                rq->nr_switches++;
+                rq->curr = next;
+                ++*switch_count;
+
+                prepare_arch_switch(rq, next);
+                prev = context_switch(rq, prev, next);
+                barrier();
+
+                finish_task_switch(prev);
+        } else
+                spin_unlock_irq(&rq->lock);
+
+        prev = current;
+        if (unlikely(reacquire_kernel_lock(prev) < 0))
+                goto need_resched_nonpreemptible;
+        preempt_enable_no_resched();
+        if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
+                goto need_resched;
+}
+
+EXPORT_SYMBOL(schedule);
+
+#ifdef CONFIG_PREEMPT
+/*
+ * this is 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 void __sched preempt_schedule(void)
+{
+        struct thread_info *ti = current_thread_info();
+#ifdef CONFIG_PREEMPT_BKL
+        struct task_struct *task = current;
+        int saved_lock_depth;
+#endif
+        /*
+         * If there is a non-zero preempt_count or interrupts are disabled,
+         * we do not want to preempt the current task.  Just return..
+         */
+        if (unlikely(ti->preempt_count || irqs_disabled()))
+                return;
+
+need_resched:
+        add_preempt_count(PREEMPT_ACTIVE);
+        /*
+         * We keep the big kernel semaphore locked, but we
+         * clear ->lock_depth so that schedule() doesnt
+         * auto-release the semaphore:
+         */
+#ifdef CONFIG_PREEMPT_BKL
+        saved_lock_depth = task->lock_depth;
+        task->lock_depth = -1;
+#endif
+        schedule();
+#ifdef CONFIG_PREEMPT_BKL
+        task->lock_depth = saved_lock_depth;
+#endif
+        sub_preempt_count(PREEMPT_ACTIVE);
+
+        /* we could miss a preemption opportunity between schedule and now */
+        barrier();
+        if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
+                goto need_resched;
+}
+
+EXPORT_SYMBOL(preempt_schedule);
+
+/*
+ * this is 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 void __sched preempt_schedule_irq(void)
+{
+        struct thread_info *ti = current_thread_info();
+#ifdef CONFIG_PREEMPT_BKL
+        struct task_struct *task = current;
+        int saved_lock_depth;
+#endif
+        /* Catch callers which need to be fixed*/
+        BUG_ON(ti->preempt_count || !irqs_disabled());
+
+need_resched:
+        add_preempt_count(PREEMPT_ACTIVE);
+        /*
+         * We keep the big kernel semaphore locked, but we
+         * clear ->lock_depth so that schedule() doesnt
+         * auto-release the semaphore:
+         */
+#ifdef CONFIG_PREEMPT_BKL
+        saved_lock_depth = task->lock_depth;
+        task->lock_depth = -1;
+#endif
+        local_irq_enable();
+        schedule();
+        local_irq_disable();
+#ifdef CONFIG_PREEMPT_BKL
+        task->lock_depth = saved_lock_depth;
+#endif
+        sub_preempt_count(PREEMPT_ACTIVE);
+
+        /* we could miss a preemption opportunity between schedule and now */
+        barrier();
+        if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
+                goto need_resched;
+}
+
+#endif /* CONFIG_PREEMPT */
+
+int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, void *key)
+{
+        task_t *p = curr->task;
+        return try_to_wake_up(p, mode, sync);
+}
+
+EXPORT_SYMBOL(default_wake_function);
+
+/*
+ * The core wakeup function.  Non-exclusive wakeups (nr_exclusive == 0) just
+ * wake everything up.  If it's an exclusive wakeup (nr_exclusive == small +ve
+ * number) then we wake all the non-exclusive tasks and one exclusive task.
+ *
+ * There are circumstances in which we can try to wake a task which has already
+ * started to run but is not in state TASK_RUNNING.  try_to_wake_up() returns
+ * zero in this (rare) case, and we handle it by continuing to scan the queue.
+ */
+static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
+                             int nr_exclusive, int sync, void *key)
+{
+        struct list_head *tmp, *next;
+
+        list_for_each_safe(tmp, next, &q->task_list) {
+                wait_queue_t *curr;
+                unsigned flags;
+                curr = list_entry(tmp, wait_queue_t, task_list);
+                flags = curr->flags;
+                if (curr->func(curr, mode, sync, key) &&
+                    (flags & WQ_FLAG_EXCLUSIVE) &&
+                    !--nr_exclusive)
+                        break;
+        }
+}
+
+/**
+ * __wake_up - wake up threads blocked on a waitqueue.
+ * @q: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ */
+void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode,
+                                int nr_exclusive, void *key)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&q->lock, flags);
+        __wake_up_common(q, mode, nr_exclusive, 0, key);
+        spin_unlock_irqrestore(&q->lock, flags);
+}
+
+EXPORT_SYMBOL(__wake_up);
+
+/*
+ * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
+ */
+void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
+{
+        __wake_up_common(q, mode, 1, 0, NULL);
+}
+
+/**
+ * __wake_up - sync- wake up threads blocked on a waitqueue.
+ * @q: the waitqueue
+ * @mode: which threads
+ * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ *
+ * The sync wakeup differs that the waker knows that it will schedule
+ * away soon, so while the target thread will be woken up, it will not
+ * be migrated to another CPU - ie. the two threads are 'synchronized'
+ * with each other. This can prevent needless bouncing between CPUs.
+ *
+ * On UP it can prevent extra preemption.
+ */
+void fastcall __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+{
+        unsigned long flags;
+        int sync = 1;
+
+        if (unlikely(!q))
+                return;
+
+        if (unlikely(!nr_exclusive))
+                sync = 0;
+
+        spin_lock_irqsave(&q->lock, flags);
+        __wake_up_common(q, mode, nr_exclusive, sync, NULL);
+        spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL_GPL(__wake_up_sync);      /* For internal use only */
+
+void fastcall complete(struct completion *x)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&x->wait.lock, flags);
+        x->done++;
+        __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
+                         1, 0, NULL);
+        spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete);
+
+void fastcall complete_all(struct completion *x)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&x->wait.lock, flags);
+        x->done += UINT_MAX/2;
+        __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
+                         0, 0, NULL);
+        spin_unlock_irqrestore(&x->wait.lock, flags);
+}
+EXPORT_SYMBOL(complete_all);
+
+void fastcall __sched wait_for_completion(struct completion *x)
+{
+        might_sleep();
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done) {
+                DECLARE_WAITQUEUE(wait, current);
+
+                wait.flags |= WQ_FLAG_EXCLUSIVE;
+                __add_wait_queue_tail(&x->wait, &wait);
+                do {
+                        __set_current_state(TASK_UNINTERRUPTIBLE);
+                        spin_unlock_irq(&x->wait.lock);
+                        schedule();
+                        spin_lock_irq(&x->wait.lock);
+                } while (!x->done);
+                __remove_wait_queue(&x->wait, &wait);
+        }
+        x->done--;
+        spin_unlock_irq(&x->wait.lock);
+}
+EXPORT_SYMBOL(wait_for_completion);
+
+unsigned long fastcall __sched
+wait_for_completion_timeout(struct completion *x, unsigned long timeout)
+{
+        might_sleep();
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done) {
+                DECLARE_WAITQUEUE(wait, current);
+
+                wait.flags |= WQ_FLAG_EXCLUSIVE;
+                __add_wait_queue_tail(&x->wait, &wait);
+                do {
+                        __set_current_state(TASK_UNINTERRUPTIBLE);
+                        spin_unlock_irq(&x->wait.lock);
+                        timeout = schedule_timeout(timeout);
+                        spin_lock_irq(&x->wait.lock);
+                        if (!timeout) {
+                                __remove_wait_queue(&x->wait, &wait);
+                                goto out;
+                        }
+                } while (!x->done);
+                __remove_wait_queue(&x->wait, &wait);
+        }
+        x->done--;
+out:
+        spin_unlock_irq(&x->wait.lock);
+        return timeout;
+}
+EXPORT_SYMBOL(wait_for_completion_timeout);
+
+int fastcall __sched wait_for_completion_interruptible(struct completion *x)
+{
+        int ret = 0;
+
+        might_sleep();
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done) {
+                DECLARE_WAITQUEUE(wait, current);
+
+                wait.flags |= WQ_FLAG_EXCLUSIVE;
+                __add_wait_queue_tail(&x->wait, &wait);
+                do {
+                        if (signal_pending(current)) {
+                                ret = -ERESTARTSYS;
+                                __remove_wait_queue(&x->wait, &wait);
+                                goto out;
+                        }
+                        __set_current_state(TASK_INTERRUPTIBLE);
+                        spin_unlock_irq(&x->wait.lock);
+                        schedule();
+                        spin_lock_irq(&x->wait.lock);
+                } while (!x->done);
+                __remove_wait_queue(&x->wait, &wait);
+        }
+        x->done--;
+out:
+        spin_unlock_irq(&x->wait.lock);
+
+        return ret;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible);
+
+unsigned long fastcall __sched
+wait_for_completion_interruptible_timeout(struct completion *x,
+                                          unsigned long timeout)
+{
+        might_sleep();
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done) {
+                DECLARE_WAITQUEUE(wait, current);
+
+                wait.flags |= WQ_FLAG_EXCLUSIVE;
+                __add_wait_queue_tail(&x->wait, &wait);
+                do {
+                        if (signal_pending(current)) {
+                                timeout = -ERESTARTSYS;
+                                __remove_wait_queue(&x->wait, &wait);
+                                goto out;
+                        }
+                        __set_current_state(TASK_INTERRUPTIBLE);
+                        spin_unlock_irq(&x->wait.lock);
+                        timeout = schedule_timeout(timeout);
+                        spin_lock_irq(&x->wait.lock);
+                        if (!timeout) {
+                                __remove_wait_queue(&x->wait, &wait);
+                                goto out;
+                        }
+                } while (!x->done);
+                __remove_wait_queue(&x->wait, &wait);
+        }
+        x->done--;
+out:
+        spin_unlock_irq(&x->wait.lock);
+        return timeout;
+}
+EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
+
+
+#define SLEEP_ON_VAR                                    \
+        unsigned long flags;                            \
+        wait_queue_t wait;                              \
+        init_waitqueue_entry(&wait, current);
+
+#define SLEEP_ON_HEAD                                   \
+        spin_lock_irqsave(&q->lock,flags);              \
+        __add_wait_queue(q, &wait);                     \
+        spin_unlock(&q->lock);
+
+#define SLEEP_ON_TAIL                                   \
+        spin_lock_irq(&q->lock);                        \
+        __remove_wait_queue(q, &wait);                  \
+        spin_unlock_irqrestore(&q->lock, flags);
+
+void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q)
+{
+        SLEEP_ON_VAR
+
+        current->state = TASK_INTERRUPTIBLE;
+
+        SLEEP_ON_HEAD
+        schedule();
+        SLEEP_ON_TAIL
+}
+
+EXPORT_SYMBOL(interruptible_sleep_on);
+
+long fastcall __sched interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
+{
+        SLEEP_ON_VAR
+
+        current->state = TASK_INTERRUPTIBLE;
+
+        SLEEP_ON_HEAD
+        timeout = schedule_timeout(timeout);
+        SLEEP_ON_TAIL
+
+        return timeout;
+}
+
+EXPORT_SYMBOL(interruptible_sleep_on_timeout);
+
+void fastcall __sched sleep_on(wait_queue_head_t *q)
+{
+        SLEEP_ON_VAR
+
+        current->state = TASK_UNINTERRUPTIBLE;
+
+        SLEEP_ON_HEAD
+        schedule();
+        SLEEP_ON_TAIL
+}
+
+EXPORT_SYMBOL(sleep_on);
+
+long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
+{
+        SLEEP_ON_VAR
+
+        current->state = TASK_UNINTERRUPTIBLE;
+
+        SLEEP_ON_HEAD
+        timeout = schedule_timeout(timeout);
+        SLEEP_ON_TAIL
+
+        return timeout;
+}
+
+EXPORT_SYMBOL(sleep_on_timeout);
+
+void set_user_nice(task_t *p, long nice)
+{
+        unsigned long flags;
+        prio_array_t *array;
+        runqueue_t *rq;
+        int old_prio, new_prio, delta;
+
+        if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
+                return;
+        /*
+         * We have to be careful, if called from sys_setpriority(),
+         * the task might be in the middle of scheduling on another CPU.
+         */
+        rq = task_rq_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:
+         */
+        if (rt_task(p)) {
+                p->static_prio = NICE_TO_PRIO(nice);
+                goto out_unlock;
+        }
+        array = p->array;
+        if (array)
+                dequeue_task(p, array);
+
+        old_prio = p->prio;
+        new_prio = NICE_TO_PRIO(nice);
+        delta = new_prio - old_prio;
+        p->static_prio = NICE_TO_PRIO(nice);
+        p->prio += delta;
+
+        if (array) {
+                enqueue_task(p, array);
+                /*
+                 * If the task increased its priority or is running and
+                 * lowered its priority, then reschedule its CPU:
+                 */
+                if (delta < 0 || (delta > 0 && task_running(rq, p)))
+                        resched_task(rq->curr);
+        }
+out_unlock:
+        task_rq_unlock(rq, &flags);
+}
+
+EXPORT_SYMBOL(set_user_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.
+ */
+asmlinkage long sys_nice(int increment)
+{
+        int retval;
+        long nice;
+
+        /*
+         * 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.
+         */
+        if (increment < 0) {
+                if (!capable(CAP_SYS_NICE))
+                        return -EPERM;
+                if (increment < -40)
+                        increment = -40;
+        }
+        if (increment > 40)
+                increment = 40;
+
+        nice = PRIO_TO_NICE(current->static_prio) + increment;
+        if (nice < -20)
+                nice = -20;
+        if (nice > 19)
+                nice = 19;
+
+        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.
+ *
+ * This is the priority value as seen by users in /proc.
+ * RT tasks are offset by -200. Normal tasks are centered
+ * around 0, value goes from -16 to +15.
+ */
+int task_prio(const task_t *p)
+{
+        return p->prio - MAX_RT_PRIO;
+}
+
+/**
+ * task_nice - return the nice value of a given task.
+ * @p: the task in question.
+ */
+int task_nice(const task_t *p)
+{
+        return TASK_NICE(p);
+}
+
+/*
+ * The only users of task_nice are binfmt_elf and binfmt_elf32.
+ * binfmt_elf is no longer modular, but binfmt_elf32 still is.
+ * Therefore, task_nice is needed if there is a compat_mode.
+ */
+#ifdef CONFIG_COMPAT
+EXPORT_SYMBOL_GPL(task_nice);
+#endif
+
+/**
+ * idle_cpu - is a given cpu idle currently?
+ * @cpu: the processor in question.
+ */
+int idle_cpu(int cpu)
+{
+        return cpu_curr(cpu) == cpu_rq(cpu)->idle;
+}
+
+EXPORT_SYMBOL_GPL(idle_cpu);
+
+/**
+ * idle_task - return the idle task for a given cpu.
+ * @cpu: the processor in question.
+ */
+task_t *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.
+ */
+static inline task_t *find_process_by_pid(pid_t pid)
+{
+        return pid ? find_task_by_pid(pid) : current;
+}
+
+/* Actually do priority change: must hold rq lock. */
+static void __setscheduler(struct task_struct *p, int policy, int prio)
+{
+        BUG_ON(p->array);
+        p->policy = policy;
+        p->rt_priority = prio;
+        if (policy != SCHED_NORMAL)
+                p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority;
+        else
+                p->prio = p->static_prio;
+}
+
+/**
+ * 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.
+ */
+int sched_setscheduler(struct task_struct *p, int policy, struct sched_param *param)
+{
+        int retval;
+        int oldprio, oldpolicy = -1;
+        prio_array_t *array;
+        unsigned long flags;
+        runqueue_t *rq;
+
+recheck:
+        /* double check policy once rq lock held */
+        if (policy < 0)
+                policy = oldpolicy = p->policy;
+        else if (policy != SCHED_FIFO && policy != SCHED_RR &&
+                                policy != SCHED_NORMAL)
+                        return -EINVAL;
+        /*
+         * Valid priorities for SCHED_FIFO and SCHED_RR are
+         * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL is 0.
+         */
+        if (param->sched_priority < 0 ||
+            param->sched_priority > MAX_USER_RT_PRIO-1)
+                return -EINVAL;
+        if ((policy == SCHED_NORMAL) != (param->sched_priority == 0))
+                return -EINVAL;
+
+        if ((policy == SCHED_FIFO || policy == SCHED_RR) &&
+            !capable(CAP_SYS_NICE))
+                return -EPERM;
+        if ((current->euid != p->euid) && (current->euid != p->uid) &&
+            !capable(CAP_SYS_NICE))
+                return -EPERM;
+
+        retval = security_task_setscheduler(p, policy, param);
+        if (retval)
+                return retval;
+        /*
+         * To be able to change p->policy safely, the apropriate
+         * runqueue lock must be held.
+         */
+        rq = task_rq_lock(p, &flags);
+        /* recheck policy now with rq lock held */
+        if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
+                policy = oldpolicy = -1;
+                task_rq_unlock(rq, &flags);
+                goto recheck;
+        }
+        array = p->array;
+        if (array)
+                deactivate_task(p, rq);
+        oldprio = p->prio;
+        __setscheduler(p, policy, param->sched_priority);
+        if (array) {
+                __activate_task(p, rq);
+                /*
+                 * Reschedule if we are currently running on this runqueue and
+                 * our priority decreased, or if we are not currently running on
+                 * this runqueue and our priority is higher than the current's
+                 */
+                if (task_running(rq, p)) {
+                        if (p->prio > oldprio)
+                                resched_task(rq->curr);
+                } else if (TASK_PREEMPTS_CURR(p, rq))
+                        resched_task(rq->curr);
+        }
+        task_rq_unlock(rq, &flags);
+        return 0;
+}
+EXPORT_SYMBOL_GPL(sched_setscheduler);
+
+static int do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+        int retval;
+        struct sched_param lparam;
+        struct task_struct *p;
+
+        if (!param || pid < 0)
+                return -EINVAL;
+        if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+                return -EFAULT;
+        read_lock_irq(&tasklist_lock);
+        p = find_process_by_pid(pid);
+        if (!p) {
+                read_unlock_irq(&tasklist_lock);
+                return -ESRCH;
+        }
+        retval = sched_setscheduler(p, policy, &lparam);
+        read_unlock_irq(&tasklist_lock);
+        return retval;
+}
+
+/**
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
+ * @pid: the pid in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ */
+asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
+                                       struct sched_param __user *param)
+{
+        return do_sched_setscheduler(pid, policy, param);
+}
+
+/**
+ * sys_sched_setparam - set/change the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the new RT priority.
+ */
+asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
+{
+        return do_sched_setscheduler(pid, -1, param);
+}
+
+/**
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
+ * @pid: the pid in question.
+ */
+asmlinkage long sys_sched_getscheduler(pid_t pid)
+{
+        int retval = -EINVAL;
+        task_t *p;
+
+        if (pid < 0)
+                goto out_nounlock;
+
+        retval = -ESRCH;
+        read_lock(&tasklist_lock);
+        p = find_process_by_pid(pid);
+        if (p) {
+                retval = security_task_getscheduler(p);
+                if (!retval)
+                        retval = p->policy;
+        }
+        read_unlock(&tasklist_lock);
+
+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.
+ */
+asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
+{
+        struct sched_param lp;
+        int retval = -EINVAL;
+        task_t *p;
+
+        if (!param || pid < 0)
+                goto out_nounlock;
+
+        read_lock(&tasklist_lock);
+        p = find_process_by_pid(pid);
+        retval = -ESRCH;
+        if (!p)
+                goto out_unlock;
+
+        retval = security_task_getscheduler(p);
+        if (retval)
+                goto out_unlock;
+
+        lp.sched_priority = p->rt_priority;
+        read_unlock(&tasklist_lock);
+
+        /*
+         * 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:
+        read_unlock(&tasklist_lock);
+        return retval;
+}
+
+long sched_setaffinity(pid_t pid, cpumask_t new_mask)
+{
+        task_t *p;
+        int retval;
+        cpumask_t cpus_allowed;
+
+        lock_cpu_hotplug();
+        read_lock(&tasklist_lock);
+
+        p = find_process_by_pid(pid);
+        if (!p) {
+                read_unlock(&tasklist_lock);
+                unlock_cpu_hotplug();
+                return -ESRCH;
+        }
+
+        /*
+         * It is not safe to call set_cpus_allowed with the
+         * tasklist_lock held.  We will bump the task_struct's
+         * usage count and then drop tasklist_lock.
+         */
+        get_task_struct(p);
+        read_unlock(&tasklist_lock);
+
+        retval = -EPERM;
+        if ((current->euid != p->euid) && (current->euid != p->uid) &&
+                        !capable(CAP_SYS_NICE))
+                goto out_unlock;
+
+        cpus_allowed = cpuset_cpus_allowed(p);
+        cpus_and(new_mask, new_mask, cpus_allowed);
+        retval = set_cpus_allowed(p, new_mask);
+
+out_unlock:
+        put_task_struct(p);
+        unlock_cpu_hotplug();
+        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
+ */
+asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
+                                      unsigned long __user *user_mask_ptr)
+{
+        cpumask_t new_mask;
+        int retval;
+
+        retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
+        if (retval)
+                return retval;
+
+        return sched_setaffinity(pid, new_mask);
+}
+
+/*
+ * Represents all cpu's present in the system
+ * In systems capable of hotplug, this map could dynamically grow
+ * as new cpu's are detected in the system via any platform specific
+ * method, such as ACPI for e.g.
+ */
+
+cpumask_t cpu_present_map;
+EXPORT_SYMBOL(cpu_present_map);
+
+#ifndef CONFIG_SMP
+cpumask_t cpu_online_map = CPU_MASK_ALL;
+cpumask_t cpu_possible_map = CPU_MASK_ALL;
+#endif
+
+long sched_getaffinity(pid_t pid, cpumask_t *mask)
+{
+        int retval;
+        task_t *p;
+
+        lock_cpu_hotplug();
+        read_lock(&tasklist_lock);
+
+        retval = -ESRCH;
+        p = find_process_by_pid(pid);
+        if (!p)
+                goto out_unlock;
+
+        retval = 0;
+        cpus_and(*mask, p->cpus_allowed, cpu_possible_map);
+
+out_unlock:
+        read_unlock(&tasklist_lock);
+        unlock_cpu_hotplug();
+        if (retval)
+                return retval;
+
+        return 0;
+}
+
+/**
+ * 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
+ */
+asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
+                                      unsigned long __user *user_mask_ptr)
+{
+        int ret;
+        cpumask_t mask;
+
+        if (len < sizeof(cpumask_t))
+                return -EINVAL;
+
+        ret = sched_getaffinity(pid, &mask);
+        if (ret < 0)
+                return ret;
+
+        if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
+                return -EFAULT;
+
+        return sizeof(cpumask_t);
+}
+
+/**
+ * sys_sched_yield - yield the current processor to other threads.
+ *
+ * this function yields the current CPU by moving the calling thread
+ * to the expired array. If there are no other threads running on this
+ * CPU then this function will return.
+ */
+asmlinkage long sys_sched_yield(void)
+{
+        runqueue_t *rq = this_rq_lock();
+        prio_array_t *array = current->array;
+        prio_array_t *target = rq->expired;
+
+        schedstat_inc(rq, yld_cnt);
+        /*
+         * We implement yielding by moving the task into the expired
+         * queue.
+         *
+         * (special rule: RT tasks will just roundrobin in the active
+         *  array.)
+         */
+        if (rt_task(current))
+                target = rq->active;
+
+        if (current->array->nr_active == 1) {
+                schedstat_inc(rq, yld_act_empty);
+                if (!rq->expired->nr_active)
+                        schedstat_inc(rq, yld_both_empty);
+        } else if (!rq->expired->nr_active)
+                schedstat_inc(rq, yld_exp_empty);
+
+        if (array != target) {
+                dequeue_task(current, array);
+                enqueue_task(current, target);
+        } else
+                /*
+                 * requeue_task is cheaper so perform that if possible.
+                 */
+                requeue_task(current, array);
+
+        /*
+         * Since we are going to call schedule() anyway, there's
+         * no need to preempt or enable interrupts:
+         */
+        __release(rq->lock);
+        _raw_spin_unlock(&rq->lock);
+        preempt_enable_no_resched();
+
+        schedule();
+
+        return 0;
+}
+
+static inline void __cond_resched(void)
+{
+        do {
+                add_preempt_count(PREEMPT_ACTIVE);
+                schedule();
+                sub_preempt_count(PREEMPT_ACTIVE);
+        } while (need_resched());
+}
+
+int __sched cond_resched(void)
+{
+        if (need_resched()) {
+                __cond_resched();
+                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)
+{
+        if (need_lockbreak(lock)) {
+                spin_unlock(lock);
+                cpu_relax();
+                spin_lock(lock);
+        }
+        if (need_resched()) {
+                _raw_spin_unlock(lock);
+                preempt_enable_no_resched();
+                __cond_resched();
+                spin_lock(lock);
+                return 1;
+        }
+        return 0;
+}
+
+EXPORT_SYMBOL(cond_resched_lock);
+
+int __sched cond_resched_softirq(void)
+{
+        BUG_ON(!in_softirq());
+
+        if (need_resched()) {
+                __local_bh_enable();
+                __cond_resched();
+                local_bh_disable();
+                return 1;
+        }
+        return 0;
+}
+
+EXPORT_SYMBOL(cond_resched_softirq);
+
+
+/**
+ * yield - yield the current processor to other threads.
+ *
+ * this is a shortcut for kernel-space yielding - it marks the
+ * thread runnable and calls sys_sched_yield().
+ */
+void __sched yield(void)
+{
+        set_current_state(TASK_RUNNING);
+        sys_sched_yield();
+}
+
+EXPORT_SYMBOL(yield);
+
+/*
+ * 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)
+ */
+void __sched io_schedule(void)
+{
+        struct runqueue *rq = &per_cpu(runqueues, _smp_processor_id());
+
+        atomic_inc(&rq->nr_iowait);
+        schedule();
+        atomic_dec(&rq->nr_iowait);
+}
+
+EXPORT_SYMBOL(io_schedule);
+
+long __sched io_schedule_timeout(long timeout)
+{
+        struct runqueue *rq = &per_cpu(runqueues, _smp_processor_id());
+        long ret;
+
+        atomic_inc(&rq->nr_iowait);
+        ret = schedule_timeout(timeout);
+        atomic_dec(&rq->nr_iowait);
+        return ret;
+}
+
+/**
+ * sys_sched_get_priority_max - return maximum RT priority.
+ * @policy: scheduling class.
+ *
+ * this syscall returns the maximum rt_priority that can be used
+ * by a given scheduling class.
+ */
+asmlinkage long sys_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:
+                ret = 0;
+                break;
+        }
+        return ret;
+}
+
+/**
+ * sys_sched_get_priority_min - return minimum RT priority.
+ * @policy: scheduling class.
+ *
+ * this syscall returns the minimum rt_priority that can be used
+ * by a given scheduling class.
+ */
+asmlinkage long sys_sched_get_priority_min(int policy)
+{
+        int ret = -EINVAL;
+
+        switch (policy) {
+        case SCHED_FIFO:
+        case SCHED_RR:
+                ret = 1;
+                break;
+        case SCHED_NORMAL:
+                ret = 0;
+        }
+        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.
+ *
+ * this syscall writes the default timeslice value of a given process
+ * into the user-space timespec buffer. A value of '0' means infinity.
+ */
+asmlinkage
+long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
+{
+        int retval = -EINVAL;
+        struct timespec t;
+        task_t *p;
+
+        if (pid < 0)
+                goto out_nounlock;
+
+        retval = -ESRCH;
+        read_lock(&tasklist_lock);
+        p = find_process_by_pid(pid);
+        if (!p)
+                goto out_unlock;
+
+        retval = security_task_getscheduler(p);
+        if (retval)
+                goto out_unlock;
+
+        jiffies_to_timespec(p->policy & SCHED_FIFO ?
+                                0 : task_timeslice(p), &t);
+        read_unlock(&tasklist_lock);
+        retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
+out_nounlock:
+        return retval;
+out_unlock:
+        read_unlock(&tasklist_lock);
+        return retval;
+}
+
+static inline struct task_struct *eldest_child(struct task_struct *p)
+{
+        if (list_empty(&p->children)) return NULL;
+        return list_entry(p->children.next,struct task_struct,sibling);
+}
+
+static inline struct task_struct *older_sibling(struct task_struct *p)
+{
+        if (p->sibling.prev==&p->parent->children) return NULL;
+        return list_entry(p->sibling.prev,struct task_struct,sibling);
+}
+
+static inline struct task_struct *younger_sibling(struct task_struct *p)
+{
+        if (p->sibling.next==&p->parent->children) return NULL;
+        return list_entry(p->sibling.next,struct task_struct,sibling);
+}
+
+static void show_task(task_t * p)
+{
+        task_t *relative;
+        unsigned state;
+        unsigned long free = 0;
+        static const char *stat_nam[] = { "R", "S", "D", "T", "t", "Z", "X" };
+
+        printk("%-13.13s ", p->comm);
+        state = p->state ? __ffs(p->state) + 1 : 0;
+        if (state < ARRAY_SIZE(stat_nam))
+                printk(stat_nam[state]);
+        else
+                printk("?");
+#if (BITS_PER_LONG == 32)
+        if (state == TASK_RUNNING)
+                printk(" running ");
+        else
+                printk(" %08lX ", thread_saved_pc(p));
+#else
+        if (state == TASK_RUNNING)
+                printk("  running task   ");
+        else
+                printk(" %016lx ", thread_saved_pc(p));
+#endif
+#ifdef CONFIG_DEBUG_STACK_USAGE
+        {
+                unsigned long * n = (unsigned long *) (p->thread_info+1);
+                while (!*n)
+                        n++;
+                free = (unsigned long) n - (unsigned long)(p->thread_info+1);
+        }
+#endif
+        printk("%5lu %5d %6d ", free, p->pid, p->parent->pid);
+        if ((relative = eldest_child(p)))
+                printk("%5d ", relative->pid);
+        else
+                printk("      ");
+        if ((relative = younger_sibling(p)))
+                printk("%7d", relative->pid);
+        else
+                printk("       ");
+        if ((relative = older_sibling(p)))
+                printk(" %5d", relative->pid);
+        else
+                printk("      ");
+        if (!p->mm)
+                printk(" (L-TLB)\n");
+        else
+                printk(" (NOTLB)\n");
+
+        if (state != TASK_RUNNING)
+                show_stack(p, NULL);
+}
+
+void show_state(void)
+{
+        task_t *g, *p;
+
+#if (BITS_PER_LONG == 32)
+        printk("\n"
+               "                                               sibling\n");
+        printk("  task             PC      pid father child younger older\n");
+#else
+        printk("\n"
+               "                                                       sibling\n");
+        printk("  task                 PC          pid father child younger older\n");
+#endif
+        read_lock(&tasklist_lock);
+        do_each_thread(g, p) {
+                /*
+                 * reset the NMI-timeout, listing all files on a slow
+                 * console might take alot of time:
+                 */
+                touch_nmi_watchdog();
+                show_task(p);
+        } while_each_thread(g, p);
+
+        read_unlock(&tasklist_lock);
+}
+
+void __devinit init_idle(task_t *idle, int cpu)
+{
+        runqueue_t *rq = cpu_rq(cpu);
+        unsigned long flags;
+
+        idle->sleep_avg = 0;
+        idle->array = NULL;
+        idle->prio = MAX_PRIO;
+        idle->state = TASK_RUNNING;
+        idle->cpus_allowed = cpumask_of_cpu(cpu);
+        set_task_cpu(idle, cpu);
+
+        spin_lock_irqsave(&rq->lock, flags);
+        rq->curr = rq->idle = idle;
+        set_tsk_need_resched(idle);
+        spin_unlock_irqrestore(&rq->lock, flags);
+
+        /* Set the preempt count _outside_ the spinlocks! */
+#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
+        idle->thread_info->preempt_count = (idle->lock_depth >= 0);
+#else
+        idle->thread_info->preempt_count = 0;
+#endif
+}
+
+/*
+ * In a system that switches off the HZ timer nohz_cpu_mask
+ * indicates which cpus entered this state. This is used
+ * in the rcu update to wait only for active cpus. For system
+ * which do not switch off the HZ timer nohz_cpu_mask should
+ * always be CPU_MASK_NONE.
+ */
+cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
+
+#ifdef CONFIG_SMP
+/*
+ * This is how migration works:
+ *
+ * 1) we queue a migration_req_t structure in the source CPU's
+ *    runqueue and wake up that CPU's migration thread.
+ * 2) we down() the locked semaphore => thread blocks.
+ * 3) migration thread wakes up (implicitly it forces the migrated
+ *    thread off the CPU)
+ * 4) it gets the migration request and checks whether the migrated
+ *    task is still in the wrong runqueue.
+ * 5) if it's in the wrong runqueue then the migration thread removes
+ *    it and puts it into the right queue.
+ * 6) migration thread up()s the semaphore.
+ * 7) we wake up and the migration is done.
+ */
+
+/*
+ * 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.
+ */
+int set_cpus_allowed(task_t *p, cpumask_t new_mask)
+{
+        unsigned long flags;
+        int ret = 0;
+        migration_req_t req;
+        runqueue_t *rq;
+
+        rq = task_rq_lock(p, &flags);
+        if (!cpus_intersects(new_mask, cpu_online_map)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        p->cpus_allowed = new_mask;
+        /* Can the task run on the task's current CPU? If so, we're done */
+        if (cpu_isset(task_cpu(p), new_mask))
+                goto out;
+
+        if (migrate_task(p, any_online_cpu(new_mask), &req)) {
+                /* Need help from migration thread: drop lock and wait. */
+                task_rq_unlock(rq, &flags);
+                wake_up_process(rq->migration_thread);
+                wait_for_completion(&req.done);
+                tlb_migrate_finish(p->mm);
+                return 0;
+        }
+out:
+        task_rq_unlock(rq, &flags);
+        return ret;
+}
+
+EXPORT_SYMBOL_GPL(set_cpus_allowed);
+
+/*
+ * Move (not current) task off this cpu, onto dest cpu.  We're doing
+ * this because either it can't run here any more (set_cpus_allowed()
+ * away from this CPU, or CPU going down), or because we're
+ * attempting to rebalance this task on exec (sched_exec).
+ *
+ * So we race with normal scheduler movements, but that's OK, as long
+ * as the task is no longer on this CPU.
+ */
+static void __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
+{
+        runqueue_t *rq_dest, *rq_src;
+
+        if (unlikely(cpu_is_offline(dest_cpu)))
+                return;
+
+        rq_src = cpu_rq(src_cpu);
+        rq_dest = cpu_rq(dest_cpu);
+
+        double_rq_lock(rq_src, rq_dest);
+        /* Already moved. */
+        if (task_cpu(p) != src_cpu)
+                goto out;
+        /* Affinity changed (again). */
+        if (!cpu_isset(dest_cpu, p->cpus_allowed))
+                goto out;
+
+        set_task_cpu(p, dest_cpu);
+        if (p->array) {
+                /*
+                 * Sync timestamp with rq_dest's before activating.
+                 * The same thing could be achieved by doing this step
+                 * afterwards, and pretending it was a local activate.
+                 * This way is cleaner and logically correct.
+                 */
+                p->timestamp = p->timestamp - rq_src->timestamp_last_tick
+                                + rq_dest->timestamp_last_tick;
+                deactivate_task(p, rq_src);
+                activate_task(p, rq_dest, 0);
+                if (TASK_PREEMPTS_CURR(p, rq_dest))
+                        resched_task(rq_dest->curr);
+        }
+
+out:
+        double_rq_unlock(rq_src, rq_dest);
+}
+
+/*
+ * migration_thread - this is a highprio system thread that performs
+ * thread migration by bumping thread off CPU then 'pushing' onto
+ * another runqueue.
+ */
+static int migration_thread(void * data)
+{
+        runqueue_t *rq;
+        int cpu = (long)data;
+
+        rq = cpu_rq(cpu);
+        BUG_ON(rq->migration_thread != current);
+
+        set_current_state(TASK_INTERRUPTIBLE);
+        while (!kthread_should_stop()) {
+                struct list_head *head;
+                migration_req_t *req;
+
+                if (current->flags & PF_FREEZE)
+                        refrigerator(PF_FREEZE);
+
+                spin_lock_irq(&rq->lock);
+
+                if (cpu_is_offline(cpu)) {
+                        spin_unlock_irq(&rq->lock);
+                        goto wait_to_die;
+                }
+
+                if (rq->active_balance) {
+                        active_load_balance(rq, cpu);
+                        rq->active_balance = 0;
+                }
+
+                head = &rq->migration_queue;
+
+                if (list_empty(head)) {
+                        spin_unlock_irq(&rq->lock);
+                        schedule();
+                        set_current_state(TASK_INTERRUPTIBLE);
+                        continue;
+                }
+                req = list_entry(head->next, migration_req_t, list);
+                list_del_init(head->next);
+
+                if (req->type == REQ_MOVE_TASK) {
+                        spin_unlock(&rq->lock);
+                        __migrate_task(req->task, cpu, req->dest_cpu);
+                        local_irq_enable();
+                } else if (req->type == REQ_SET_DOMAIN) {
+                        rq->sd = req->sd;
+                        spin_unlock_irq(&rq->lock);
+                } else {
+                        spin_unlock_irq(&rq->lock);
+                        WARN_ON(1);
+                }
+
+                complete(&req->done);
+        }
+        __set_current_state(TASK_RUNNING);
+        return 0;
+
+wait_to_die:
+        /* Wait for kthread_stop */
+        set_current_state(TASK_INTERRUPTIBLE);
+        while (!kthread_should_stop()) {
+                schedule();
+                set_current_state(TASK_INTERRUPTIBLE);
+        }
+        __set_current_state(TASK_RUNNING);
+        return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+/* Figure out where task on dead CPU should go, use force if neccessary. */
+static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *tsk)
+{
+        int dest_cpu;
+        cpumask_t mask;
+
+        /* On same node? */
+        mask = node_to_cpumask(cpu_to_node(dead_cpu));
+        cpus_and(mask, mask, tsk->cpus_allowed);
+        dest_cpu = any_online_cpu(mask);
+
+        /* On any allowed CPU? */
+        if (dest_cpu == NR_CPUS)
+                dest_cpu = any_online_cpu(tsk->cpus_allowed);
+
+        /* No more Mr. Nice Guy. */
+        if (dest_cpu == NR_CPUS) {
+                tsk->cpus_allowed = cpuset_cpus_allowed(tsk);
+                dest_cpu = any_online_cpu(tsk->cpus_allowed);
+
+                /*
+                 * Don't tell them about moving exiting tasks or
+                 * kernel threads (both mm NULL), since they never
+                 * leave kernel.
+                 */
+                if (tsk->mm && printk_ratelimit())
+                        printk(KERN_INFO "process %d (%s) no "
+                               "longer affine to cpu%d\n",
+                               tsk->pid, tsk->comm, dead_cpu);
+        }
+        __migrate_task(tsk, dead_cpu, dest_cpu);
+}
+
+/*
+ * While a dead CPU has no uninterruptible tasks queued at this point,
+ * it might still have a nonzero ->nr_uninterruptible counter, because
+ * for performance reasons the counter is not stricly tracking tasks to
+ * their home CPUs. So we just add the counter to another CPU's counter,
+ * to keep the global sum constant after CPU-down:
+ */
+static void migrate_nr_uninterruptible(runqueue_t *rq_src)
+{
+        runqueue_t *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL));
+        unsigned long flags;
+
+        local_irq_save(flags);
+        double_rq_lock(rq_src, rq_dest);
+        rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
+        rq_src->nr_uninterruptible = 0;
+        double_rq_unlock(rq_src, rq_dest);
+        local_irq_restore(flags);
+}
+
+/* Run through task list and migrate tasks from the dead cpu. */
+static void migrate_live_tasks(int src_cpu)
+{
+        struct task_struct *tsk, *t;
+
+        write_lock_irq(&tasklist_lock);
+
+        do_each_thread(t, tsk) {
+                if (tsk == current)
+                        continue;
+
+                if (task_cpu(tsk) == src_cpu)
+                        move_task_off_dead_cpu(src_cpu, tsk);
+        } while_each_thread(t, tsk);
+
+        write_unlock_irq(&tasklist_lock);
+}
+
+/* Schedules idle task to be the next runnable task on current CPU.
+ * It does so by boosting its priority to highest possible and adding it to
+ * the _front_ of runqueue. Used by CPU offline code.
+ */
+void sched_idle_next(void)
+{
+        int cpu = smp_processor_id();
+        runqueue_t *rq = this_rq();
+        struct task_struct *p = rq->idle;
+        unsigned long flags;
+
+        /* cpu has to be offline */
+        BUG_ON(cpu_online(cpu));
+
+        /* Strictly not necessary since rest of the CPUs are stopped by now
+         * and interrupts disabled on current cpu.
+         */
+        spin_lock_irqsave(&rq->lock, flags);
+
+        __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1);
+        /* Add idle task to _front_ of it's priority queue */
+        __activate_idle_task(p, rq);
+
+        spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+/* 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);
+        mmdrop(mm);
+}
+
+static void migrate_dead(unsigned int dead_cpu, task_t *tsk)
+{
+        struct runqueue *rq = cpu_rq(dead_cpu);
+
+        /* Must be exiting, otherwise would be on tasklist. */
+        BUG_ON(tsk->exit_state != EXIT_ZOMBIE && tsk->exit_state != EXIT_DEAD);
+
+        /* Cannot have done final schedule yet: would have vanished. */
+        BUG_ON(tsk->flags & PF_DEAD);
+
+        get_task_struct(tsk);
+
+        /*
+         * Drop lock around migration; if someone else moves it,
+         * that's OK.  No task can be added to this CPU, so iteration is
+         * fine.
+         */
+        spin_unlock_irq(&rq->lock);
+        move_task_off_dead_cpu(dead_cpu, tsk);
+        spin_lock_irq(&rq->lock);
+
+        put_task_struct(tsk);
+}
+
+/* release_task() removes task from tasklist, so we won't find dead tasks. */
+static void migrate_dead_tasks(unsigned int dead_cpu)
+{
+        unsigned arr, i;
+        struct runqueue *rq = cpu_rq(dead_cpu);
+
+        for (arr = 0; arr < 2; arr++) {
+                for (i = 0; i < MAX_PRIO; i++) {
+                        struct list_head *list = &rq->arrays[arr].queue[i];
+                        while (!list_empty(list))
+                                migrate_dead(dead_cpu,
+                                             list_entry(list->next, task_t,
+                                                        run_list));
+                }
+        }
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+/*
+ * migration_call - callback that gets triggered when a CPU is added.
+ * Here we can start up the necessary migration thread for the new CPU.
+ */
+static int migration_call(struct notifier_block *nfb, unsigned long action,
+                          void *hcpu)
+{
+        int cpu = (long)hcpu;
+        struct task_struct *p;
+        struct runqueue *rq;
+        unsigned long flags;
+
+        switch (action) {
+        case CPU_UP_PREPARE:
+                p = kthread_create(migration_thread, hcpu, "migration/%d",cpu);
+                if (IS_ERR(p))
+                        return NOTIFY_BAD;
+                p->flags |= PF_NOFREEZE;
+                kthread_bind(p, cpu);
+                /* Must be high prio: stop_machine expects to yield to it. */
+                rq = task_rq_lock(p, &flags);
+                __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1);
+                task_rq_unlock(rq, &flags);
+                cpu_rq(cpu)->migration_thread = p;
+                break;
+        case CPU_ONLINE:
+                /* Strictly unneccessary, as first user will wake it. */
+                wake_up_process(cpu_rq(cpu)->migration_thread);
+                break;
+#ifdef CONFIG_HOTPLUG_CPU
+        case CPU_UP_CANCELED:
+                /* Unbind it from offline cpu so it can run.  Fall thru. */
+                kthread_bind(cpu_rq(cpu)->migration_thread,smp_processor_id());
+                kthread_stop(cpu_rq(cpu)->migration_thread);
+                cpu_rq(cpu)->migration_thread = NULL;
+                break;
+        case CPU_DEAD:
+                migrate_live_tasks(cpu);
+                rq = cpu_rq(cpu);
+                kthread_stop(rq->migration_thread);
+                rq->migration_thread = NULL;
+                /* Idle task back to normal (off runqueue, low prio) */
+                rq = task_rq_lock(rq->idle, &flags);
+                deactivate_task(rq->idle, rq);
+                rq->idle->static_prio = MAX_PRIO;
+                __setscheduler(rq->idle, SCHED_NORMAL, 0);
+                migrate_dead_tasks(cpu);
+                task_rq_unlock(rq, &flags);
+                migrate_nr_uninterruptible(rq);
+                BUG_ON(rq->nr_running != 0);
+
+                /* No need to migrate the tasks: it was best-effort if
+                 * they didn't do lock_cpu_hotplug().  Just wake up
+                 * the requestors. */
+                spin_lock_irq(&rq->lock);
+                while (!list_empty(&rq->migration_queue)) {
+                        migration_req_t *req;
+                        req = list_entry(rq->migration_queue.next,
+                                         migration_req_t, list);
+                        BUG_ON(req->type != REQ_MOVE_TASK);
+                        list_del_init(&req->list);
+                        complete(&req->done);
+                }
+                spin_unlock_irq(&rq->lock);
+                break;
+#endif
+        }
+        return NOTIFY_OK;
+}
+
+/* Register at highest priority so that task migration (migrate_all_tasks)
+ * happens before everything else.
+ */
+static struct notifier_block __devinitdata migration_notifier = {
+        .notifier_call = migration_call,
+        .priority = 10
+};
+
+int __init migration_init(void)
+{
+        void *cpu = (void *)(long)smp_processor_id();
+        /* Start one for boot CPU. */
+        migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+        migration_call(&migration_notifier, CPU_ONLINE, cpu);
+        register_cpu_notifier(&migration_notifier);
+        return 0;
+}
+#endif
+
+#ifdef CONFIG_SMP
+#define SCHED_DOMAIN_DEBUG
+#ifdef SCHED_DOMAIN_DEBUG
+static void sched_domain_debug(struct sched_domain *sd, int cpu)
+{
+        int level = 0;
+
+        printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
+
+        do {
+                int i;
+                char str[NR_CPUS];
+                struct sched_group *group = sd->groups;
+                cpumask_t groupmask;
+
+                cpumask_scnprintf(str, NR_CPUS, sd->span);
+                cpus_clear(groupmask);
+
+                printk(KERN_DEBUG);
+                for (i = 0; i < level + 1; i++)
+                        printk(" ");
+                printk("domain %d: ", 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");
+                        break;
+                }
+
+                printk("span %s\n", str);
+
+                if (!cpu_isset(cpu, sd->span))
+                        printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu);
+                if (!cpu_isset(cpu, group->cpumask))
+                        printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu);
+
+                printk(KERN_DEBUG);
+                for (i = 0; i < level + 2; i++)
+                        printk(" ");
+                printk("groups:");
+                do {
+                        if (!group) {
+                                printk("\n");
+                                printk(KERN_ERR "ERROR: group is NULL\n");
+                                break;
+                        }
+
+                        if (!group->cpu_power) {
+                                printk("\n");
+                                printk(KERN_ERR "ERROR: domain->cpu_power not set\n");
+                        }
+
+                        if (!cpus_weight(group->cpumask)) {
+                                printk("\n");
+                                printk(KERN_ERR "ERROR: empty group\n");
+                        }
+
+                        if (cpus_intersects(groupmask, group->cpumask)) {
+                                printk("\n");
+                                printk(KERN_ERR "ERROR: repeated CPUs\n");
+                        }
+
+                        cpus_or(groupmask, groupmask, group->cpumask);
+
+                        cpumask_scnprintf(str, NR_CPUS, group->cpumask);
+                        printk(" %s", str);
+
+                        group = group->next;
+                } while (group != sd->groups);
+                printk("\n");
+
+                if (!cpus_equal(sd->span, groupmask))
+                        printk(KERN_ERR "ERROR: groups don't span domain->span\n");
+
+                level++;
+                sd = sd->parent;
+
+                if (sd) {
+                        if (!cpus_subset(groupmask, sd->span))
+                                printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n");
+                }
+
+        } while (sd);
+}
+#else
+#define sched_domain_debug(sd, cpu) {}
+#endif
+
+/*
+ * Attach the domain 'sd' to 'cpu' as its base domain.  Callers must
+ * hold the hotplug lock.
+ */
+void __devinit cpu_attach_domain(struct sched_domain *sd, int cpu)
+{
+        migration_req_t req;
+        unsigned long flags;
+        runqueue_t *rq = cpu_rq(cpu);
+        int local = 1;
+
+        sched_domain_debug(sd, cpu);
+
+        spin_lock_irqsave(&rq->lock, flags);
+
+        if (cpu == smp_processor_id() || !cpu_online(cpu)) {
+                rq->sd = sd;
+        } else {
+                init_completion(&req.done);
+                req.type = REQ_SET_DOMAIN;
+                req.sd = sd;
+                list_add(&req.list, &rq->migration_queue);
+                local = 0;
+        }
+
+        spin_unlock_irqrestore(&rq->lock, flags);
+
+        if (!local) {
+                wake_up_process(rq->migration_thread);
+                wait_for_completion(&req.done);
+        }
+}
+
+/* cpus with isolated domains */
+cpumask_t __devinitdata cpu_isolated_map = CPU_MASK_NONE;
+
+/* Setup the mask of cpus configured for isolated domains */
+static int __init isolated_cpu_setup(char *str)
+{
+        int ints[NR_CPUS], i;
+
+        str = get_options(str, ARRAY_SIZE(ints), ints);
+        cpus_clear(cpu_isolated_map);
+        for (i = 1; i <= ints[0]; i++)
+                if (ints[i] < NR_CPUS)
+                        cpu_set(ints[i], cpu_isolated_map);
+        return 1;
+}
+
+__setup ("isolcpus=", isolated_cpu_setup);
+
+/*
+ * init_sched_build_groups takes an array of groups, the cpumask we wish
+ * to span, and a pointer to a function which identifies what group a CPU
+ * belongs to. The return value of group_fn must be a valid index into the
+ * groups[] array, and must be >= 0 and < NR_CPUS (due to the fact that we
+ * keep track of groups covered with a cpumask_t).
+ *
+ * init_sched_build_groups will build a circular linked list of the groups
+ * covered by the given span, and will set each group's ->cpumask correctly,
+ * and ->cpu_power to 0.
+ */
+void __devinit init_sched_build_groups(struct sched_group groups[],
+                        cpumask_t span, int (*group_fn)(int cpu))
+{
+        struct sched_group *first = NULL, *last = NULL;
+        cpumask_t covered = CPU_MASK_NONE;
+        int i;
+
+        for_each_cpu_mask(i, span) {
+                int group = group_fn(i);
+                struct sched_group *sg = &groups[group];
+                int j;
+
+                if (cpu_isset(i, covered))
+                        continue;
+
+                sg->cpumask = CPU_MASK_NONE;
+                sg->cpu_power = 0;
+
+                for_each_cpu_mask(j, span) {
+                        if (group_fn(j) != group)
+                                continue;
+
+                        cpu_set(j, covered);
+                        cpu_set(j, sg->cpumask);
+                }
+                if (!first)
+                        first = sg;
+                if (last)
+                        last->next = sg;
+                last = sg;
+        }
+        last->next = first;
+}
+
+
+#ifdef ARCH_HAS_SCHED_DOMAIN
+extern void __devinit arch_init_sched_domains(void);
+extern void __devinit arch_destroy_sched_domains(void);
+#else
+#ifdef CONFIG_SCHED_SMT
+static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
+static struct sched_group sched_group_cpus[NR_CPUS];
+static int __devinit cpu_to_cpu_group(int cpu)
+{
+        return cpu;
+}
+#endif
+
+static DEFINE_PER_CPU(struct sched_domain, phys_domains);
+static struct sched_group sched_group_phys[NR_CPUS];
+static int __devinit cpu_to_phys_group(int cpu)
+{
+#ifdef CONFIG_SCHED_SMT
+        return first_cpu(cpu_sibling_map[cpu]);
+#else
+        return cpu;
+#endif
+}
+
+#ifdef CONFIG_NUMA
+
+static DEFINE_PER_CPU(struct sched_domain, node_domains);
+static struct sched_group sched_group_nodes[MAX_NUMNODES];
+static int __devinit cpu_to_node_group(int cpu)
+{
+        return cpu_to_node(cpu);
+}
+#endif
+
+#if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA)
+/*
+ * The domains setup code relies on siblings not spanning
+ * multiple nodes. Make sure the architecture has a proper
+ * siblings map:
+ */
+static void check_sibling_maps(void)
+{
+        int i, j;
+
+        for_each_online_cpu(i) {
+                for_each_cpu_mask(j, cpu_sibling_map[i]) {
+                        if (cpu_to_node(i) != cpu_to_node(j)) {
+                                printk(KERN_INFO "warning: CPU %d siblings map "
+                                        "to different node - isolating "
+                                        "them.\n", i);
+                                cpu_sibling_map[i] = cpumask_of_cpu(i);
+                                break;
+                        }
+                }
+        }
+}
+#endif
+
+/*
+ * Set up scheduler domains and groups.  Callers must hold the hotplug lock.
+ */
+static void __devinit arch_init_sched_domains(void)
+{
+        int i;
+        cpumask_t cpu_default_map;
+
+#if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA)
+        check_sibling_maps();
+#endif
+        /*
+         * Setup mask for cpus without special case scheduling requirements.
+         * For now this just excludes isolated cpus, but could be used to
+         * exclude other special cases in the future.
+         */
+        cpus_complement(cpu_default_map, cpu_isolated_map);
+        cpus_and(cpu_default_map, cpu_default_map, cpu_online_map);
+
+        /*
+         * Set up domains. Isolated domains just stay on the dummy domain.
+         */
+        for_each_cpu_mask(i, cpu_default_map) {
+                int group;
+                struct sched_domain *sd = NULL, *p;
+                cpumask_t nodemask = node_to_cpumask(cpu_to_node(i));
+
+                cpus_and(nodemask, nodemask, cpu_default_map);
+
+#ifdef CONFIG_NUMA
+                sd = &per_cpu(node_domains, i);
+                group = cpu_to_node_group(i);
+                *sd = SD_NODE_INIT;
+                sd->span = cpu_default_map;
+                sd->groups = &sched_group_nodes[group];
+#endif
+
+                p = sd;
+                sd = &per_cpu(phys_domains, i);
+                group = cpu_to_phys_group(i);
+                *sd = SD_CPU_INIT;
+                sd->span = nodemask;
+                sd->parent = p;
+                sd->groups = &sched_group_phys[group];
+
+#ifdef CONFIG_SCHED_SMT
+                p = sd;
+                sd = &per_cpu(cpu_domains, i);
+                group = cpu_to_cpu_group(i);
+                *sd = SD_SIBLING_INIT;
+                sd->span = cpu_sibling_map[i];
+                cpus_and(sd->span, sd->span, cpu_default_map);
+                sd->parent = p;
+                sd->groups = &sched_group_cpus[group];
+#endif
+        }
+
+#ifdef CONFIG_SCHED_SMT
+        /* Set up CPU (sibling) groups */
+        for_each_online_cpu(i) {
+                cpumask_t this_sibling_map = cpu_sibling_map[i];
+                cpus_and(this_sibling_map, this_sibling_map, cpu_default_map);
+                if (i != first_cpu(this_sibling_map))
+                        continue;
+
+                init_sched_build_groups(sched_group_cpus, this_sibling_map,
+                                                &cpu_to_cpu_group);
+        }
+#endif
+
+        /* Set up physical groups */
+        for (i = 0; i < MAX_NUMNODES; i++) {
+                cpumask_t nodemask = node_to_cpumask(i);
+
+                cpus_and(nodemask, nodemask, cpu_default_map);
+                if (cpus_empty(nodemask))
+                        continue;
+
+                init_sched_build_groups(sched_group_phys, nodemask,
+                                                &cpu_to_phys_group);
+        }
+
+#ifdef CONFIG_NUMA
+        /* Set up node groups */
+        init_sched_build_groups(sched_group_nodes, cpu_default_map,
+                                        &cpu_to_node_group);
+#endif
+
+        /* Calculate CPU power for physical packages and nodes */
+        for_each_cpu_mask(i, cpu_default_map) {
+                int power;
+                struct sched_domain *sd;
+#ifdef CONFIG_SCHED_SMT
+                sd = &per_cpu(cpu_domains, i);
+                power = SCHED_LOAD_SCALE;
+                sd->groups->cpu_power = power;
+#endif
+
+                sd = &per_cpu(phys_domains, i);
+                power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE *
+                                (cpus_weight(sd->groups->cpumask)-1) / 10;
+                sd->groups->cpu_power = power;
+
+#ifdef CONFIG_NUMA
+                if (i == first_cpu(sd->groups->cpumask)) {
+                        /* Only add "power" once for each physical package. */
+                        sd = &per_cpu(node_domains, i);
+                        sd->groups->cpu_power += power;
+                }
+#endif
+        }
+
+        /* Attach the domains */
+        for_each_online_cpu(i) {
+                struct sched_domain *sd;
+#ifdef CONFIG_SCHED_SMT
+                sd = &per_cpu(cpu_domains, i);
+#else
+                sd = &per_cpu(phys_domains, i);
+#endif
+                cpu_attach_domain(sd, i);
+        }
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void __devinit arch_destroy_sched_domains(void)
+{
+        /* Do nothing: everything is statically allocated. */
+}
+#endif
+
+#endif /* ARCH_HAS_SCHED_DOMAIN */
+
+/*
+ * Initial dummy domain for early boot and for hotplug cpu. Being static,
+ * it is initialized to zero, so all balancing flags are cleared which is
+ * what we want.
+ */
+static struct sched_domain sched_domain_dummy;
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Force a reinitialization of the sched domains hierarchy.  The domains
+ * and groups cannot be updated in place without racing with the balancing
+ * code, so we temporarily attach all running cpus to a "dummy" domain
+ * which will prevent rebalancing while the sched domains are recalculated.
+ */
+static int update_sched_domains(struct notifier_block *nfb,
+                                unsigned long action, void *hcpu)
+{
+        int i;
+
+        switch (action) {
+        case CPU_UP_PREPARE:
+        case CPU_DOWN_PREPARE:
+                for_each_online_cpu(i)
+                        cpu_attach_domain(&sched_domain_dummy, i);
+                arch_destroy_sched_domains();
+                return NOTIFY_OK;
+
+        case CPU_UP_CANCELED:
+        case CPU_DOWN_FAILED:
+        case CPU_ONLINE:
+        case CPU_DEAD:
+                /*
+                 * Fall through and re-initialise the domains.
+                 */
+                break;
+        default:
+                return NOTIFY_DONE;
+        }
+
+        /* The hotplug lock is already held by cpu_up/cpu_down */
+        arch_init_sched_domains();
+
+        return NOTIFY_OK;
+}
+#endif
+
+void __init sched_init_smp(void)
+{
+        lock_cpu_hotplug();
+        arch_init_sched_domains();
+        unlock_cpu_hotplug();
+        /* XXX: Theoretical race here - CPU may be hotplugged now */
+        hotcpu_notifier(update_sched_domains, 0);
+}
+#else
+void __init sched_init_smp(void)
+{
+}
+#endif /* CONFIG_SMP */
+
+int in_sched_functions(unsigned long addr)
+{
+        /* Linker adds these: start and end of __sched functions */
+        extern char __sched_text_start[], __sched_text_end[];
+        return in_lock_functions(addr) ||
+                (addr >= (unsigned long)__sched_text_start
+                && addr < (unsigned long)__sched_text_end);
+}
+
+void __init sched_init(void)
+{
+        runqueue_t *rq;
+        int i, j, k;
+
+        for (i = 0; i < NR_CPUS; i++) {
+                prio_array_t *array;
+
+                rq = cpu_rq(i);
+                spin_lock_init(&rq->lock);
+                rq->active = rq->arrays;
+                rq->expired = rq->arrays + 1;
+                rq->best_expired_prio = MAX_PRIO;
+
+#ifdef CONFIG_SMP
+                rq->sd = &sched_domain_dummy;
+                rq->cpu_load = 0;
+                rq->active_balance = 0;
+                rq->push_cpu = 0;
+                rq->migration_thread = NULL;
+                INIT_LIST_HEAD(&rq->migration_queue);
+#endif
+                atomic_set(&rq->nr_iowait, 0);
+
+                for (j = 0; j < 2; j++) {
+                        array = rq->arrays + j;
+                        for (k = 0; k < MAX_PRIO; k++) {
+                                INIT_LIST_HEAD(array->queue + k);
+                                __clear_bit(k, array->bitmap);
+                        }
+                        // delimiter for bitsearch
+                        __set_bit(MAX_PRIO, array->bitmap);
+                }
+        }
+
+        /*
+         * 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_DEBUG_SPINLOCK_SLEEP
+void __might_sleep(char *file, int line)
+{
+#if defined(in_atomic)
+        static unsigned long prev_jiffy;        /* ratelimiting */
+
+        if ((in_atomic() || irqs_disabled()) &&
+            system_state == SYSTEM_RUNNING && !oops_in_progress) {
+                if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+                        return;
+                prev_jiffy = jiffies;
+                printk(KERN_ERR "Debug: sleeping function called from invalid"
+                                " context at %s:%d\n", file, line);
+                printk("in_atomic():%d, irqs_disabled():%d\n",
+                        in_atomic(), irqs_disabled());
+                dump_stack();
+        }
+#endif
+}
+EXPORT_SYMBOL(__might_sleep);
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+void normalize_rt_tasks(void)
+{
+        struct task_struct *p;
+        prio_array_t *array;
+        unsigned long flags;
+        runqueue_t *rq;
+
+        read_lock_irq(&tasklist_lock);
+        for_each_process (p) {
+                if (!rt_task(p))
+                        continue;
+
+                rq = task_rq_lock(p, &flags);
+
+                array = p->array;
+                if (array)
+                        deactivate_task(p, task_rq(p));
+                __setscheduler(p, SCHED_NORMAL, 0);
+                if (array) {
+                        __activate_task(p, task_rq(p));
+                        resched_task(rq->curr);
+                }
+
+                task_rq_unlock(rq, &flags);
+        }
+        read_unlock_irq(&tasklist_lock);
+}
+
+#endif /* CONFIG_MAGIC_SYSRQ */