2.6.24-git20

 kernel

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index da7c061..6c091d6 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -20,6 +20,8 @@
  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
  */
 
+#include <linux/latencytop.h>
+
 /*
  * Targeted preemption latency for CPU-bound tasks:
  * (default: 20ms * (1 + ilog(ncpus)), units: nanoseconds)
@@ -248,8 +250,8 @@ static u64 __sched_period(unsigned long nr_running)
    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;
@@ -383,6 +385,9 @@ 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);
 }
 
@@ -434,6 +439,7 @@ 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;
@@ -443,9 +449,12 @@ 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;
@@ -462,11 +471,11 @@ 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
 }
@@ -511,7 +520,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
 
    if (!initial) {
       /* sleeps upto a single latency don't count. */
-      if (sched_feat(NEW_FAIR_SLEEPERS) && entity_is_task(se))
+      if (sched_feat(NEW_FAIR_SLEEPERS))
          vruntime -= sysctl_sched_latency;
 
       /* ensure we never gain time by being placed backwards. */
@@ -642,13 +651,29 @@ 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);
 
+#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);
 }
@@ -690,7 +715,7 @@ 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
@@ -707,6 +732,8 @@ static inline struct sched_entity *parent_entity(struct sched_entity *se)
    return se->parent;
 }
 
+#define GROUP_IMBALANCE_PCT   20
+
 #else   /* CONFIG_FAIR_GROUP_SCHED */
 
 #define for_each_sched_entity(se) \
@@ -752,6 +779,43 @@ 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
@@ -760,15 +824,28 @@ static inline struct sched_entity *parent_entity(struct sched_entity *se)
 static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
 {
    struct cfs_rq *cfs_rq;
-   struct sched_entity *se = &p->se;
+   struct sched_entity *se = &p->se,
+             *topse = NULL;   /* Highest schedulable entity */
+   int incload = 1;
 
    for_each_sched_entity(se) {
-      if (se->on_rq)
+      topse = se;
+      if (se->on_rq) {
+         incload = 0;
          break;
+      }
       cfs_rq = cfs_rq_of(se);
       enqueue_entity(cfs_rq, se, wakeup);
       wakeup = 1;
    }
+   /* Increment cpu load if we just enqueued the first task of a group on
+    * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs
+    * at the highest grouping level.
+    */
+   if (incload)
+      inc_cpu_load(rq, topse->load.weight);
+
+   hrtick_start_fair(rq, rq->curr);
 }
 
 /*
@@ -779,16 +856,30 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
 static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
 {
    struct cfs_rq *cfs_rq;
-   struct sched_entity *se = &p->se;
+   struct sched_entity *se = &p->se,
+             *topse = NULL;    /* Highest schedulable entity */
+   int decload = 1;
 
    for_each_sched_entity(se) {
+      topse = se;
       cfs_rq = cfs_rq_of(se);
       dequeue_entity(cfs_rq, se, sleep);
       /* Don't dequeue parent if it has other entities besides us */
-      if (cfs_rq->load.weight)
+      if (cfs_rq->load.weight) {
+         if (parent_entity(se))
+            decload = 0;
          break;
+      }
       sleep = 1;
    }
+   /* Decrement cpu load if we just dequeued the last task of a group on
+    * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs
+    * at the highest grouping level.
+    */
+   if (decload)
+      dec_cpu_load(rq, topse->load.weight);
+
+   hrtick_start_fair(rq, rq->curr);
 }
 
 /*
@@ -836,6 +927,154 @@ 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)
@@ -867,7 +1106,11 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
    }
 
    gran = sysctl_sched_wakeup_granularity;
-   if (unlikely(se->load.weight != NICE_0_LOAD))
+   /*
+    * 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 (pse->vruntime + gran < se->vruntime)
@@ -876,6 +1119,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
 
 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;
 
@@ -887,7 +1131,10 @@ 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;
 }
 
 /*
@@ -944,25 +1191,6 @@ static struct task_struct *load_balance_next_fair(void *arg)
    return __load_balance_iterator(cfs_rq, cfs_rq->rb_load_balance_curr);
 }
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-static int cfs_rq_best_prio(struct cfs_rq *cfs_rq)
-{
-   struct sched_entity *curr;
-   struct task_struct *p;
-
-   if (!cfs_rq->nr_running)
-      return MAX_PRIO;
-
-   curr = cfs_rq->curr;
-   if (!curr)
-      curr = __pick_next_entity(cfs_rq);
-
-   p = task_of(curr);
-
-   return p->prio;
-}
-#endif
-
 static unsigned long
 load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
         unsigned long max_load_move,
@@ -972,28 +1200,45 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
    struct cfs_rq *busy_cfs_rq;
    long rem_load_move = max_load_move;
    struct rq_iterator cfs_rq_iterator;
+   unsigned long load_moved;
 
    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) {
 #ifdef CONFIG_FAIR_GROUP_SCHED
-      struct cfs_rq *this_cfs_rq;
-      long imbalance;
-      unsigned long maxload;
+      struct cfs_rq *this_cfs_rq = busy_cfs_rq->tg->cfs_rq[this_cpu];
+      unsigned long maxload, task_load, group_weight;
+      unsigned long thisload, per_task_load;
+      struct sched_entity *se = busy_cfs_rq->tg->se[busiest->cpu];
+
+      task_load = busy_cfs_rq->load.weight;
+      group_weight = se->load.weight;
 
-      this_cfs_rq = cpu_cfs_rq(busy_cfs_rq, this_cpu);
+      /*
+       * 'group_weight' is contributed by tasks of total weight
+       * 'task_load'. To move 'rem_load_move' worth of weight only,
+       * we need to move a maximum task load of:
+       *
+       *    maxload = (remload / group_weight) * task_load;
+       */
+      maxload = (rem_load_move * task_load) / group_weight;
 
-      imbalance = busy_cfs_rq->load.weight - this_cfs_rq->load.weight;
-      /* Don't pull if this_cfs_rq has more load than busy_cfs_rq */
-      if (imbalance <= 0)
+      if (!maxload || !task_load)
          continue;
 
-      /* Don't pull more than imbalance/2 */
-      imbalance /= 2;
-      maxload = min(rem_load_move, imbalance);
+      per_task_load = task_load / busy_cfs_rq->nr_running;
+      /*
+       * balance_tasks will try to forcibly move atleast one task if
+       * possible (because of SCHED_LOAD_SCALE_FUZZ). Avoid that if
+       * maxload is less than GROUP_IMBALANCE_FUZZ% the per_task_load.
+       */
+       if (100 * maxload < GROUP_IMBALANCE_PCT * per_task_load)
+         continue;
 
-      *this_best_prio = cfs_rq_best_prio(this_cfs_rq);
+      /* Disable priority-based load balance */
+      *this_best_prio = 0;
+      thisload = this_cfs_rq->load.weight;
 #else
 # define maxload rem_load_move
 #endif
@@ -1002,11 +1247,33 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
        * load_balance_[start|next]_fair iterators
        */
       cfs_rq_iterator.arg = busy_cfs_rq;
-      rem_load_move -= balance_tasks(this_rq, this_cpu, busiest,
+      load_moved = balance_tasks(this_rq, this_cpu, busiest,
                       maxload, sd, idle, all_pinned,
                       this_best_prio,
                       &cfs_rq_iterator);
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+      /*
+       * load_moved holds the task load that was moved. The
+       * effective (group) weight moved would be:
+       *    load_moved_eff = load_moved/task_load * group_weight;
+       */
+      load_moved = (group_weight * load_moved) / task_load;
+
+      /* Adjust shares on both cpus to reflect load_moved */
+      group_weight -= load_moved;
+      set_se_shares(se, group_weight);
+
+      se = busy_cfs_rq->tg->se[this_cpu];
+      if (!thisload)
+         group_weight = load_moved;
+      else
+         group_weight = se->load.weight + load_moved;
+      set_se_shares(se, group_weight);
+#endif
+
+      rem_load_move -= load_moved;
+
       if (rem_load_move <= 0)
          break;
    }
@@ -1042,14 +1309,14 @@ move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 /*
  * 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);
    }
 }
 
@@ -1087,6 +1354,42 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
    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
@@ -1108,6 +1411,9 @@ 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,
 
@@ -1122,6 +1428,9 @@ static const struct sched_class fair_sched_class = {
    .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_SCHED_DEBUG
@@ -1132,7 +1441,9 @@ 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