acer-wmi: Rename mail LED correctly & remove hardcoded colour
[safe/jmp/linux-2.6] / kernel / sched_fair.c
index a9dfb77..e2a5305 100644 (file)
  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
  */
 
+#include <linux/latencytop.h>
+
 /*
  * Targeted preemption latency for CPU-bound tasks:
- * (default: 20ms, units: nanoseconds)
+ * (default: 20ms * (1 + ilog(ncpus)), units: nanoseconds)
  *
  * NOTE: this latency value is not the same as the concept of
- * 'timeslice length' - timeslices in CFS are of variable length.
- * (to see the precise effective timeslice length of your workload,
- *  run vmstat and monitor the context-switches field)
+ * 'timeslice length' - timeslices in CFS are of variable length
+ * and have no persistent notion like in traditional, time-slice
+ * based scheduling concepts.
  *
- * On SMP systems the value of this is multiplied by the log2 of the
- * number of CPUs. (i.e. factor 2x on 2-way systems, 3x on 4-way
- * systems, 4x on 8-way systems, 5x on 16-way systems, etc.)
- * Targeted preemption latency for CPU-bound tasks:
+ * (to see the precise effective timeslice length of your workload,
+ *  run vmstat and monitor the context-switches (cs) field)
  */
-const_debug unsigned int sysctl_sched_latency = 20000000ULL;
+unsigned int sysctl_sched_latency = 20000000ULL;
 
 /*
- * After fork, child runs first. (default) If set to 0 then
- * parent will (try to) run first.
+ * Minimal preemption granularity for CPU-bound tasks:
+ * (default: 4 msec * (1 + ilog(ncpus)), units: nanoseconds)
  */
-const_debug unsigned int sysctl_sched_child_runs_first = 1;
+unsigned int sysctl_sched_min_granularity = 4000000ULL;
 
 /*
- * Minimal preemption granularity for CPU-bound tasks:
- * (default: 2 msec, units: nanoseconds)
+ * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
+ */
+static unsigned int sched_nr_latency = 5;
+
+/*
+ * After fork, child runs first. (default) If set to 0 then
+ * parent will (try to) run first.
  */
-const_debug unsigned int sysctl_sched_nr_latency = 20;
+const_debug unsigned int sysctl_sched_child_runs_first = 1;
 
 /*
  * sys_sched_yield() compat mode
@@ -58,23 +63,25 @@ unsigned int __read_mostly sysctl_sched_compat_yield;
 
 /*
  * SCHED_BATCH wake-up granularity.
- * (default: 10 msec, units: nanoseconds)
+ * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
  *
  * This option delays the preemption effects of decoupled workloads
  * and reduces their over-scheduling. Synchronous workloads will still
  * have immediate wakeup/sleep latencies.
  */
-const_debug unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL;
+unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL;
 
 /*
  * SCHED_OTHER wake-up granularity.
- * (default: 10 msec, units: nanoseconds)
+ * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
  *
  * This option delays the preemption effects of decoupled workloads
  * and reduces their over-scheduling. Synchronous workloads will still
  * have immediate wakeup/sleep latencies.
  */
-const_debug unsigned int sysctl_sched_wakeup_granularity = 10000000UL;
+unsigned int sysctl_sched_wakeup_granularity = 10000000UL;
+
+const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
 
 /**************************************************************
  * CFS operations on generic schedulable entities:
@@ -195,23 +202,34 @@ static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq)
 
 static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
 {
-       struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
-       struct sched_entity *se = NULL;
-       struct rb_node *parent;
+       struct rb_node *last = rb_last(&cfs_rq->tasks_timeline);
 
-       while (*link) {
-               parent = *link;
-               se = rb_entry(parent, struct sched_entity, run_node);
-               link = &parent->rb_right;
-       }
+       if (!last)
+               return NULL;
 
-       return se;
+       return rb_entry(last, struct sched_entity, run_node);
 }
 
 /**************************************************************
  * Scheduling class statistics methods:
  */
 
+#ifdef CONFIG_SCHED_DEBUG
+int sched_nr_latency_handler(struct ctl_table *table, int write,
+               struct file *filp, void __user *buffer, size_t *lenp,
+               loff_t *ppos)
+{
+       int ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+
+       if (ret || !write)
+               return ret;
+
+       sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency,
+                                       sysctl_sched_min_granularity);
+
+       return 0;
+}
+#endif
 
 /*
  * The idea is to set a period in which each task runs once.
@@ -224,11 +242,11 @@ static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
 static u64 __sched_period(unsigned long nr_running)
 {
        u64 period = sysctl_sched_latency;
-       unsigned long nr_latency = sysctl_sched_nr_latency;
+       unsigned long nr_latency = sched_nr_latency;
 
        if (unlikely(nr_running > nr_latency)) {
+               period = sysctl_sched_min_granularity;
                period *= nr_running;
-               do_div(period, nr_latency);
        }
 
        return period;
@@ -259,6 +277,7 @@ static u64 __sched_vslice(unsigned long rq_weight, unsigned long nr_running)
 {
        u64 vslice = __sched_period(nr_running);
 
+       vslice *= NICE_0_LOAD;
        do_div(vslice, rq_weight);
 
        return vslice;
@@ -329,6 +348,12 @@ static void update_curr(struct cfs_rq *cfs_rq)
 
        __update_curr(cfs_rq, curr, delta_exec);
        curr->exec_start = now;
+
+       if (entity_is_task(curr)) {
+               struct task_struct *curtask = task_of(curr);
+
+               cpuacct_charge(curtask, delta_exec);
+       }
 }
 
 static inline void
@@ -355,6 +380,9 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
        schedstat_set(se->wait_max, max(se->wait_max,
                        rq_of(cfs_rq)->clock - se->wait_start));
+       schedstat_set(se->wait_count, se->wait_count + 1);
+       schedstat_set(se->wait_sum, se->wait_sum +
+                       rq_of(cfs_rq)->clock - se->wait_start);
        schedstat_set(se->wait_start, 0);
 }
 
@@ -381,15 +409,6 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
        se->exec_start = rq_of(cfs_rq)->clock;
 }
 
-/*
- * We are descheduling a task - update its stats:
- */
-static inline void
-update_stats_curr_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-       se->exec_start = 0;
-}
-
 /**************************************************
  * Scheduling class queueing methods:
  */
@@ -415,6 +434,7 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 #ifdef CONFIG_SCHEDSTATS
        if (se->sleep_start) {
                u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
+               struct task_struct *tsk = task_of(se);
 
                if ((s64)delta < 0)
                        delta = 0;
@@ -424,9 +444,12 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 
                se->sleep_start = 0;
                se->sum_sleep_runtime += delta;
+
+               account_scheduler_latency(tsk, delta >> 10, 1);
        }
        if (se->block_start) {
                u64 delta = rq_of(cfs_rq)->clock - se->block_start;
+               struct task_struct *tsk = task_of(se);
 
                if ((s64)delta < 0)
                        delta = 0;
@@ -443,11 +466,11 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
                 * time that the task spent sleeping:
                 */
                if (unlikely(prof_on == SLEEP_PROFILING)) {
-                       struct task_struct *tsk = task_of(se);
 
                        profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk),
                                     delta >> 20);
                }
+               account_scheduler_latency(tsk, delta >> 10, 0);
        }
 #endif
 }
@@ -481,18 +504,25 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
        } else if (sched_feat(APPROX_AVG) && cfs_rq->nr_running)
                vruntime += sched_vslice(cfs_rq)/2;
 
+       /*
+        * The 'current' period is already promised to the current tasks,
+        * however the extra weight of the new task will slow them down a
+        * little, place the new task so that it fits in the slot that
+        * stays open at the end.
+        */
        if (initial && sched_feat(START_DEBIT))
                vruntime += sched_vslice_add(cfs_rq, se);
 
        if (!initial) {
+               /* sleeps upto a single latency don't count. */
                if (sched_feat(NEW_FAIR_SLEEPERS))
                        vruntime -= sysctl_sched_latency;
 
-               vruntime = max_t(s64, vruntime, se->vruntime);
+               /* ensure we never gain time by being placed backwards. */
+               vruntime = max_vruntime(se->vruntime, vruntime);
        }
 
        se->vruntime = vruntime;
-
 }
 
 static void
@@ -607,8 +637,6 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
        if (prev->on_rq)
                update_curr(cfs_rq);
 
-       update_stats_curr_end(cfs_rq, prev);
-
        check_spread(cfs_rq, prev);
        if (prev->on_rq) {
                update_stats_wait_start(cfs_rq, prev);
@@ -618,14 +646,30 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
        cfs_rq->curr = NULL;
 }
 
-static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+static void
+entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 {
        /*
         * Update run-time statistics of the 'current'.
         */
        update_curr(cfs_rq);
 
-       if (cfs_rq->nr_running > 1)
+#ifdef CONFIG_SCHED_HRTICK
+       /*
+        * queued ticks are scheduled to match the slice, so don't bother
+        * validating it and just reschedule.
+        */
+       if (queued)
+               return resched_task(rq_of(cfs_rq)->curr);
+       /*
+        * don't let the period tick interfere with the hrtick preemption
+        */
+       if (!sched_feat(DOUBLE_TICK) &&
+                       hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
+               return;
+#endif
+
+       if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT))
                check_preempt_tick(cfs_rq, curr);
 }
 
@@ -666,7 +710,7 @@ static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
 
 /* Iterate thr' all leaf cfs_rq's on a runqueue */
 #define for_each_leaf_cfs_rq(rq, cfs_rq) \
-       list_for_each_entry(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list)
+       list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list)
 
 /* Do the two (enqueued) entities belong to the same group ? */
 static inline int
@@ -728,6 +772,43 @@ static inline struct sched_entity *parent_entity(struct sched_entity *se)
 
 #endif /* CONFIG_FAIR_GROUP_SCHED */
 
+#ifdef CONFIG_SCHED_HRTICK
+static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+       int requeue = rq->curr == p;
+       struct sched_entity *se = &p->se;
+       struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+       WARN_ON(task_rq(p) != rq);
+
+       if (hrtick_enabled(rq) && cfs_rq->nr_running > 1) {
+               u64 slice = sched_slice(cfs_rq, se);
+               u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
+               s64 delta = slice - ran;
+
+               if (delta < 0) {
+                       if (rq->curr == p)
+                               resched_task(p);
+                       return;
+               }
+
+               /*
+                * Don't schedule slices shorter than 10000ns, that just
+                * doesn't make sense. Rely on vruntime for fairness.
+                */
+               if (!requeue)
+                       delta = max(10000LL, delta);
+
+               hrtick_start(rq, delta, requeue);
+       }
+}
+#else
+static inline void
+hrtick_start_fair(struct rq *rq, struct task_struct *p)
+{
+}
+#endif
+
 /*
  * The enqueue_task method is called before nr_running is
  * increased. Here we update the fair scheduling stats and
@@ -745,6 +826,8 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
                enqueue_entity(cfs_rq, se, wakeup);
                wakeup = 1;
        }
+
+       hrtick_start_fair(rq, rq->curr);
 }
 
 /*
@@ -765,6 +848,8 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
                        break;
                sleep = 1;
        }
+
+       hrtick_start_fair(rq, rq->curr);
 }
 
 /*
@@ -774,8 +859,9 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
  */
 static void yield_task_fair(struct rq *rq)
 {
-       struct cfs_rq *cfs_rq = task_cfs_rq(rq->curr);
-       struct sched_entity *rightmost, *se = &rq->curr->se;
+       struct task_struct *curr = rq->curr;
+       struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+       struct sched_entity *rightmost, *se = &curr->se;
 
        /*
         * Are we the only task in the tree?
@@ -783,7 +869,7 @@ static void yield_task_fair(struct rq *rq)
        if (unlikely(cfs_rq->nr_running == 1))
                return;
 
-       if (likely(!sysctl_sched_compat_yield)) {
+       if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {
                __update_rq_clock(rq);
                /*
                 * Update run-time statistics of the 'current'.
@@ -811,6 +897,154 @@ static void yield_task_fair(struct rq *rq)
 }
 
 /*
+ * 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, struct task_struct *p)
+{
+       cpumask_t tmp;
+       struct sched_domain *sd;
+       int i;
+
+       /*
+        * If it is idle, then it is the best cpu to run this task.
+        *
+        * This cpu is also the best, if it has more than one task already.
+        * Siblings must be also busy(in most cases) as they didn't already
+        * pickup the extra load from this cpu and hence we need not check
+        * sibling runqueue info. This will avoid the checks and cache miss
+        * penalities associated with that.
+        */
+       if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1)
+               return cpu;
+
+       for_each_domain(cpu, sd) {
+               if (sd->flags & SD_WAKE_IDLE) {
+                       cpus_and(tmp, sd->span, p->cpus_allowed);
+                       for_each_cpu_mask(i, tmp) {
+                               if (idle_cpu(i)) {
+                                       if (i != task_cpu(p)) {
+                                               schedstat_inc(p,
+                                                      se.nr_wakeups_idle);
+                                       }
+                                       return i;
+                               }
+                       }
+               } else {
+                       break;
+               }
+       }
+       return cpu;
+}
+#else
+static inline int wake_idle(int cpu, struct task_struct *p)
+{
+       return cpu;
+}
+#endif
+
+#ifdef CONFIG_SMP
+static int select_task_rq_fair(struct task_struct *p, int sync)
+{
+       int cpu, this_cpu;
+       struct rq *rq;
+       struct sched_domain *sd, *this_sd = NULL;
+       int new_cpu;
+
+       cpu      = task_cpu(p);
+       rq       = task_rq(p);
+       this_cpu = smp_processor_id();
+       new_cpu  = cpu;
+
+       if (cpu == this_cpu)
+               goto out_set_cpu;
+
+       for_each_domain(this_cpu, sd) {
+               if (cpu_isset(cpu, sd->span)) {
+                       this_sd = sd;
+                       break;
+               }
+       }
+
+       if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
+               goto out_set_cpu;
+
+       /*
+        * Check for affine wakeup and passive balancing possibilities.
+        */
+       if (this_sd) {
+               int idx = this_sd->wake_idx;
+               unsigned int imbalance;
+               unsigned long load, this_load;
+
+               imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
+
+               load = source_load(cpu, idx);
+               this_load = target_load(this_cpu, idx);
+
+               new_cpu = this_cpu; /* Wake to this CPU if we can */
+
+               if (this_sd->flags & SD_WAKE_AFFINE) {
+                       unsigned long tl = this_load;
+                       unsigned long tl_per_task;
+
+                       /*
+                        * Attract cache-cold tasks on sync wakeups:
+                        */
+                       if (sync && !task_hot(p, rq->clock, this_sd))
+                               goto out_set_cpu;
+
+                       schedstat_inc(p, se.nr_wakeups_affine_attempts);
+                       tl_per_task = cpu_avg_load_per_task(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)
+                               tl -= current->se.load.weight;
+
+                       if ((tl <= load &&
+                               tl + target_load(cpu, idx) <= tl_per_task) ||
+                              100*(tl + p->se.load.weight) <= imbalance*load) {
+                               /*
+                                * This domain has SD_WAKE_AFFINE and
+                                * p is cache cold in this domain, and
+                                * there is no bad imbalance.
+                                */
+                               schedstat_inc(this_sd, ttwu_move_affine);
+                               schedstat_inc(p, se.nr_wakeups_affine);
+                               goto out_set_cpu;
+                       }
+               }
+
+               /*
+                * Start passive balancing when half the imbalance_pct
+                * limit is reached.
+                */
+               if (this_sd->flags & SD_WAKE_BALANCE) {
+                       if (imbalance*this_load <= 100*load) {
+                               schedstat_inc(this_sd, ttwu_move_balance);
+                               schedstat_inc(p, se.nr_wakeups_passive);
+                               goto out_set_cpu;
+                       }
+               }
+       }
+
+       new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
+out_set_cpu:
+       return wake_idle(new_cpu, p);
+}
+#endif /* CONFIG_SMP */
+
+
+/*
  * Preempt the current task with a newly woken task if needed:
  */
 static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
@@ -818,7 +1052,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
        struct task_struct *curr = rq->curr;
        struct cfs_rq *cfs_rq = task_cfs_rq(curr);
        struct sched_entity *se = &curr->se, *pse = &p->se;
-       s64 delta;
+       unsigned long gran;
 
        if (unlikely(rt_prio(p->prio))) {
                update_rq_clock(rq);
@@ -826,20 +1060,36 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
                resched_task(curr);
                return;
        }
+       /*
+        * Batch tasks do not preempt (their preemption is driven by
+        * the tick):
+        */
+       if (unlikely(p->policy == SCHED_BATCH))
+               return;
+
+       if (!sched_feat(WAKEUP_PREEMPT))
+               return;
 
        while (!is_same_group(se, pse)) {
                se = parent_entity(se);
                pse = parent_entity(pse);
        }
 
-       delta = se->vruntime - pse->vruntime;
+       gran = sysctl_sched_wakeup_granularity;
+       /*
+        * More easily preempt - nice tasks, while not making
+        * it harder for + nice tasks.
+        */
+       if (unlikely(se->load.weight > NICE_0_LOAD))
+               gran = calc_delta_fair(gran, &se->load);
 
-       if (delta > (s64)sysctl_sched_wakeup_granularity)
+       if (pse->vruntime + gran < se->vruntime)
                resched_task(curr);
 }
 
 static struct task_struct *pick_next_task_fair(struct rq *rq)
 {
+       struct task_struct *p;
        struct cfs_rq *cfs_rq = &rq->cfs;
        struct sched_entity *se;
 
@@ -851,7 +1101,10 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
                cfs_rq = group_cfs_rq(se);
        } while (cfs_rq);
 
-       return task_of(se);
+       p = task_of(se);
+       hrtick_start_fair(rq, p);
+
+       return p;
 }
 
 /*
@@ -868,6 +1121,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
        }
 }
 
+#ifdef CONFIG_SMP
 /**************************************************
  * Fair scheduling class load-balancing methods:
  */
@@ -913,7 +1167,7 @@ static int cfs_rq_best_prio(struct cfs_rq *cfs_rq)
        struct sched_entity *curr;
        struct task_struct *p;
 
-       if (!cfs_rq->nr_running)
+       if (!cfs_rq->nr_running || !first_fair(cfs_rq))
                return MAX_PRIO;
 
        curr = cfs_rq->curr;
@@ -928,12 +1182,11 @@ static int cfs_rq_best_prio(struct cfs_rq *cfs_rq)
 
 static unsigned long
 load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
-                 unsigned long max_nr_move, unsigned long max_load_move,
+                 unsigned long max_load_move,
                  struct sched_domain *sd, enum cpu_idle_type idle,
                  int *all_pinned, int *this_best_prio)
 {
        struct cfs_rq *busy_cfs_rq;
-       unsigned long load_moved, total_nr_moved = 0, nr_moved;
        long rem_load_move = max_load_move;
        struct rq_iterator cfs_rq_iterator;
 
@@ -961,40 +1214,63 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 #else
 # define maxload rem_load_move
 #endif
-               /* pass busy_cfs_rq argument into
+               /*
+                * pass busy_cfs_rq argument into
                 * load_balance_[start|next]_fair iterators
                 */
                cfs_rq_iterator.arg = busy_cfs_rq;
-               nr_moved = balance_tasks(this_rq, this_cpu, busiest,
-                               max_nr_move, maxload, sd, idle, all_pinned,
-                               &load_moved, this_best_prio, &cfs_rq_iterator);
+               rem_load_move -= balance_tasks(this_rq, this_cpu, busiest,
+                                              maxload, sd, idle, all_pinned,
+                                              this_best_prio,
+                                              &cfs_rq_iterator);
 
-               total_nr_moved += nr_moved;
-               max_nr_move -= nr_moved;
-               rem_load_move -= load_moved;
-
-               if (max_nr_move <= 0 || rem_load_move <= 0)
+               if (rem_load_move <= 0)
                        break;
        }
 
        return max_load_move - rem_load_move;
 }
 
+static int
+move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
+                  struct sched_domain *sd, enum cpu_idle_type idle)
+{
+       struct cfs_rq *busy_cfs_rq;
+       struct rq_iterator cfs_rq_iterator;
+
+       cfs_rq_iterator.start = load_balance_start_fair;
+       cfs_rq_iterator.next = load_balance_next_fair;
+
+       for_each_leaf_cfs_rq(busiest, busy_cfs_rq) {
+               /*
+                * pass busy_cfs_rq argument into
+                * load_balance_[start|next]_fair iterators
+                */
+               cfs_rq_iterator.arg = busy_cfs_rq;
+               if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle,
+                                      &cfs_rq_iterator))
+                   return 1;
+       }
+
+       return 0;
+}
+#endif
+
 /*
  * scheduler tick hitting a task of our scheduling class:
  */
-static void task_tick_fair(struct rq *rq, struct task_struct *curr)
+static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
 {
        struct cfs_rq *cfs_rq;
        struct sched_entity *se = &curr->se;
 
        for_each_sched_entity(se) {
                cfs_rq = cfs_rq_of(se);
-               entity_tick(cfs_rq, se);
+               entity_tick(cfs_rq, se, queued);
        }
 }
 
-#define swap(a,b) do { typeof(a) tmp = (a); (a) = (b); (b) = tmp; } while (0)
+#define swap(a, b) do { typeof(a) tmp = (a); (a) = (b); (b) = tmp; } while (0)
 
 /*
  * Share the fairness runtime between parent and child, thus the
@@ -1007,14 +1283,16 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
 {
        struct cfs_rq *cfs_rq = task_cfs_rq(p);
        struct sched_entity *se = &p->se, *curr = cfs_rq->curr;
+       int this_cpu = smp_processor_id();
 
        sched_info_queued(p);
 
        update_curr(cfs_rq);
        place_entity(cfs_rq, se, 1);
 
-       if (sysctl_sched_child_runs_first &&
-                       curr->vruntime < se->vruntime) {
+       /* 'curr' will be NULL if the child belongs to a different group */
+       if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) &&
+                       curr && curr->vruntime < se->vruntime) {
                /*
                 * Upon rescheduling, sched_class::put_prev_task() will place
                 * 'current' within the tree based on its new key value.
@@ -1022,14 +1300,46 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
                swap(curr->vruntime, se->vruntime);
        }
 
-       update_stats_enqueue(cfs_rq, se);
-       check_spread(cfs_rq, se);
-       check_spread(cfs_rq, curr);
-       __enqueue_entity(cfs_rq, se);
-       account_entity_enqueue(cfs_rq, se);
+       enqueue_task_fair(rq, p, 0);
        resched_task(rq->curr);
 }
 
+/*
+ * Priority of the task has changed. Check to see if we preempt
+ * the current task.
+ */
+static void prio_changed_fair(struct rq *rq, struct task_struct *p,
+                             int oldprio, int running)
+{
+       /*
+        * 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 (running) {
+               if (p->prio > oldprio)
+                       resched_task(rq->curr);
+       } else
+               check_preempt_curr(rq, p);
+}
+
+/*
+ * We switched to the sched_fair class.
+ */
+static void switched_to_fair(struct rq *rq, struct task_struct *p,
+                            int running)
+{
+       /*
+        * We were most likely switched from sched_rt, so
+        * kick off the schedule if running, otherwise just see
+        * if we can still preempt the current task.
+        */
+       if (running)
+               resched_task(rq->curr);
+       else
+               check_preempt_curr(rq, p);
+}
+
 /* Account for a task changing its policy or group.
  *
  * This routine is mostly called to set cfs_rq->curr field when a task
@@ -1043,6 +1353,16 @@ static void set_curr_task_fair(struct rq *rq)
                set_next_entity(cfs_rq_of(se), se);
 }
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void moved_group_fair(struct task_struct *p)
+{
+       struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+       update_curr(cfs_rq);
+       place_entity(cfs_rq, &p->se, 1);
+}
+#endif
+
 /*
  * All the scheduling class methods:
  */
@@ -1051,17 +1371,30 @@ static const struct sched_class fair_sched_class = {
        .enqueue_task           = enqueue_task_fair,
        .dequeue_task           = dequeue_task_fair,
        .yield_task             = yield_task_fair,
+#ifdef CONFIG_SMP
+       .select_task_rq         = select_task_rq_fair,
+#endif /* CONFIG_SMP */
 
        .check_preempt_curr     = check_preempt_wakeup,
 
        .pick_next_task         = pick_next_task_fair,
        .put_prev_task          = put_prev_task_fair,
 
+#ifdef CONFIG_SMP
        .load_balance           = load_balance_fair,
+       .move_one_task          = move_one_task_fair,
+#endif
 
        .set_curr_task          = set_curr_task_fair,
        .task_tick              = task_tick_fair,
        .task_new               = task_new_fair,
+
+       .prio_changed           = prio_changed_fair,
+       .switched_to            = switched_to_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       .moved_group            = moved_group_fair,
+#endif
 };
 
 #ifdef CONFIG_SCHED_DEBUG
@@ -1072,7 +1405,9 @@ static void print_cfs_stats(struct seq_file *m, int cpu)
 #ifdef CONFIG_FAIR_GROUP_SCHED
        print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs);
 #endif
+       rcu_read_lock();
        for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
                print_cfs_rq(m, cpu, cfs_rq);
+       rcu_read_unlock();
 }
 #endif