2.6.24

 kernel

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 67c67a8..da7c061 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -22,25 +22,34 @@
 
 /*
  * 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)
  */
-unsigned int sysctl_sched_latency __read_mostly = 20000000ULL;
+unsigned int sysctl_sched_latency = 20000000ULL;
 
 /*
  * Minimal preemption granularity for CPU-bound tasks:
- * (default: 2 msec, units: nanoseconds)
+ * (default: 4 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ */
+unsigned int sysctl_sched_min_granularity = 4000000ULL;
+
+/*
+ * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
  */
-unsigned int sysctl_sched_min_granularity __read_mostly = 2000000ULL;
+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_child_runs_first = 1;
 
 /*
  * sys_sched_yield() compat mode
@@ -52,52 +61,25 @@ unsigned int __read_mostly sysctl_sched_compat_yield;
 
 /*
  * SCHED_BATCH wake-up granularity.
- * (default: 25 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.
  */
-unsigned int sysctl_sched_batch_wakeup_granularity __read_mostly = 25000000UL;
+unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL;
 
 /*
  * SCHED_OTHER wake-up granularity.
- * (default: 1 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.
  */
-unsigned int sysctl_sched_wakeup_granularity __read_mostly = 1000000UL;
+unsigned int sysctl_sched_wakeup_granularity = 10000000UL;
 
-unsigned int sysctl_sched_stat_granularity __read_mostly;
-
-/*
- * Initialized in sched_init_granularity() [to 5 times the base granularity]:
- */
-unsigned int sysctl_sched_runtime_limit __read_mostly;
-
-/*
- * Debugging: various feature bits
- */
-enum {
-   SCHED_FEAT_FAIR_SLEEPERS   = 1,
-   SCHED_FEAT_SLEEPER_AVG      = 2,
-   SCHED_FEAT_SLEEPER_LOAD_AVG   = 4,
-   SCHED_FEAT_PRECISE_CPU_LOAD   = 8,
-   SCHED_FEAT_START_DEBIT      = 16,
-   SCHED_FEAT_SKIP_INITIAL      = 32,
-};
-
-unsigned int sysctl_sched_features __read_mostly =
-      SCHED_FEAT_FAIR_SLEEPERS   *1 |
-      SCHED_FEAT_SLEEPER_AVG      *0 |
-      SCHED_FEAT_SLEEPER_LOAD_AVG   *1 |
-      SCHED_FEAT_PRECISE_CPU_LOAD   *1 |
-      SCHED_FEAT_START_DEBIT      *1 |
-      SCHED_FEAT_SKIP_INITIAL      *0;
-
-extern struct sched_class fair_sched_class;
+const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
 
 /**************************************************************
  * CFS operations on generic schedulable entities:
@@ -111,21 +93,9 @@ static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
    return cfs_rq->rq;
 }
 
-/* currently running entity (if any) on this cfs_rq */
-static inline struct sched_entity *cfs_rq_curr(struct cfs_rq *cfs_rq)
-{
-   return cfs_rq->curr;
-}
-
 /* An entity is a task if it doesn't "own" a runqueue */
 #define entity_is_task(se)   (!se->my_q)
 
-static inline void
-set_cfs_rq_curr(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-   cfs_rq->curr = se;
-}
-
 #else   /* CONFIG_FAIR_GROUP_SCHED */
 
 static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
@@ -133,21 +103,8 @@ static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
    return container_of(cfs_rq, struct rq, cfs);
 }
 
-static inline struct sched_entity *cfs_rq_curr(struct cfs_rq *cfs_rq)
-{
-   struct rq *rq = rq_of(cfs_rq);
-
-   if (unlikely(rq->curr->sched_class != &fair_sched_class))
-      return NULL;
-
-   return &rq->curr->se;
-}
-
 #define entity_is_task(se)   1
 
-static inline void
-set_cfs_rq_curr(struct cfs_rq *cfs_rq, struct sched_entity *se) { }
-
 #endif   /* CONFIG_FAIR_GROUP_SCHED */
 
 static inline struct task_struct *task_of(struct sched_entity *se)
@@ -160,16 +117,38 @@ static inline struct task_struct *task_of(struct sched_entity *se)
  * Scheduling class tree data structure manipulation methods:
  */
 
+static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime)
+{
+   s64 delta = (s64)(vruntime - min_vruntime);
+   if (delta > 0)
+      min_vruntime = vruntime;
+
+   return min_vruntime;
+}
+
+static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
+{
+   s64 delta = (s64)(vruntime - min_vruntime);
+   if (delta < 0)
+      min_vruntime = vruntime;
+
+   return min_vruntime;
+}
+
+static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+   return se->vruntime - cfs_rq->min_vruntime;
+}
+
 /*
  * Enqueue an entity into the rb-tree:
  */
-static inline void
-__enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
    struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
    struct rb_node *parent = NULL;
    struct sched_entity *entry;
-   s64 key = se->fair_key;
+   s64 key = entity_key(cfs_rq, se);
    int leftmost = 1;
 
    /*
@@ -182,7 +161,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
        * We dont care about collisions. Nodes with
        * the same key stay together.
        */
-      if (key - entry->fair_key < 0) {
+      if (key < entity_key(cfs_rq, entry)) {
          link = &parent->rb_left;
       } else {
          link = &parent->rb_right;
@@ -199,24 +178,14 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 
    rb_link_node(&se->run_node, parent, link);
    rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline);
-   update_load_add(&cfs_rq->load, se->load.weight);
-   cfs_rq->nr_running++;
-   se->on_rq = 1;
-
-   schedstat_add(cfs_rq, wait_runtime, se->wait_runtime);
 }
 
-static inline void
-__dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
    if (cfs_rq->rb_leftmost == &se->run_node)
       cfs_rq->rb_leftmost = rb_next(&se->run_node);
-   rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
-   update_load_sub(&cfs_rq->load, se->load.weight);
-   cfs_rq->nr_running--;
-   se->on_rq = 0;
 
-   schedstat_add(cfs_rq, wait_runtime, -se->wait_runtime);
+   rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
 }
 
 static inline struct rb_node *first_fair(struct cfs_rq *cfs_rq)
@@ -229,118 +198,103 @@ static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq)
    return rb_entry(first_fair(cfs_rq), struct sched_entity, run_node);
 }
 
+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;
+
+   while (*link) {
+      parent = *link;
+      se = rb_entry(parent, struct sched_entity, run_node);
+      link = &parent->rb_right;
+   }
+
+   return se;
+}
+
 /**************************************************************
  * 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
+
 /*
- * Calculate the preemption granularity needed to schedule every
- * runnable task once per sysctl_sched_latency amount of time.
- * (down to a sensible low limit on granularity)
- *
- * For example, if there are 2 tasks running and latency is 10 msecs,
- * we switch tasks every 5 msecs. If we have 3 tasks running, we have
- * to switch tasks every 3.33 msecs to get a 10 msecs observed latency
- * for each task. We do finer and finer scheduling up to until we
- * reach the minimum granularity value.
- *
- * To achieve this we use the following dynamic-granularity rule:
- *
- *    gran = lat/nr - lat/nr/nr
- *
- * This comes out of the following equations:
+ * The idea is to set a period in which each task runs once.
  *
- *    kA1 + gran = kB1
- *    kB2 + gran = kA2
- *    kA2 = kA1
- *    kB2 = kB1 - d + d/nr
- *    lat = d * nr
+ * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch
+ * this period because otherwise the slices get too small.
  *
- * Where 'k' is key, 'A' is task A (waiting), 'B' is task B (running),
- * '1' is start of time, '2' is end of time, 'd' is delay between
- * 1 and 2 (during which task B was running), 'nr' is number of tasks
- * running, 'lat' is the the period of each task. ('lat' is the
- * sched_latency that we aim for.)
+ * p = (nr <= nl) ? l : l*nr/nl
  */
-static long
-sched_granularity(struct cfs_rq *cfs_rq)
+static u64 __sched_period(unsigned long nr_running)
 {
-   unsigned int gran = sysctl_sched_latency;
-   unsigned int nr = cfs_rq->nr_running;
+   u64 period = sysctl_sched_latency;
+   unsigned long nr_latency = sched_nr_latency;
 
-   if (nr > 1) {
-      gran = gran/nr - gran/nr/nr;
-      gran = max(gran, sysctl_sched_min_granularity);
+   if (unlikely(nr_running > nr_latency)) {
+      period *= nr_running;
+      do_div(period, nr_latency);
    }
 
-   return gran;
+   return period;
 }
 
 /*
- * We rescale the rescheduling granularity of tasks according to their
- * nice level, but only linearly, not exponentially:
+ * We calculate the wall-time slice from the period by taking a part
+ * proportional to the weight.
+ *
+ * s = p*w/rw
  */
-static long
-niced_granularity(struct sched_entity *curr, unsigned long granularity)
+static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   u64 tmp;
+   u64 slice = __sched_period(cfs_rq->nr_running);
 
-   if (likely(curr->load.weight == NICE_0_LOAD))
-      return granularity;
-   /*
-    * Positive nice levels get the same granularity as nice-0:
-    */
-   if (likely(curr->load.weight < NICE_0_LOAD)) {
-      tmp = curr->load.weight * (u64)granularity;
-      return (long) (tmp >> NICE_0_SHIFT);
-   }
-   /*
-    * Negative nice level tasks get linearly finer
-    * granularity:
-    */
-   tmp = curr->load.inv_weight * (u64)granularity;
+   slice *= se->load.weight;
+   do_div(slice, cfs_rq->load.weight);
 
-   /*
-    * It will always fit into 'long':
-    */
-   return (long) (tmp >> (WMULT_SHIFT-NICE_0_SHIFT));
+   return slice;
 }
 
-static inline void
-limit_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se)
+/*
+ * We calculate the vruntime slice.
+ *
+ * vs = s/w = p/rw
+ */
+static u64 __sched_vslice(unsigned long rq_weight, unsigned long nr_running)
 {
-   long limit = sysctl_sched_runtime_limit;
+   u64 vslice = __sched_period(nr_running);
 
-   /*
-    * Niced tasks have the same history dynamic range as
-    * non-niced tasks:
-    */
-   if (unlikely(se->wait_runtime > limit)) {
-      se->wait_runtime = limit;
-      schedstat_inc(se, wait_runtime_overruns);
-      schedstat_inc(cfs_rq, wait_runtime_overruns);
-   }
-   if (unlikely(se->wait_runtime < -limit)) {
-      se->wait_runtime = -limit;
-      schedstat_inc(se, wait_runtime_underruns);
-      schedstat_inc(cfs_rq, wait_runtime_underruns);
-   }
+   vslice *= NICE_0_LOAD;
+   do_div(vslice, rq_weight);
+
+   return vslice;
 }
 
-static inline void
-__add_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se, long delta)
+static u64 sched_vslice(struct cfs_rq *cfs_rq)
 {
-   se->wait_runtime += delta;
-   schedstat_add(se, sum_wait_runtime, delta);
-   limit_wait_runtime(cfs_rq, se);
+   return __sched_vslice(cfs_rq->load.weight, cfs_rq->nr_running);
 }
 
-static void
-add_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se, long delta)
+static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   schedstat_add(cfs_rq, wait_runtime, -se->wait_runtime);
-   __add_wait_runtime(cfs_rq, se, delta);
-   schedstat_add(cfs_rq, wait_runtime, se->wait_runtime);
+   return __sched_vslice(cfs_rq->load.weight + se->load.weight,
+         cfs_rq->nr_running + 1);
 }
 
 /*
@@ -348,46 +302,41 @@ add_wait_runtime(struct cfs_rq *cfs_rq, struct sched_entity *se, long delta)
  * are not in our scheduling class.
  */
 static inline void
-__update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+__update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
+         unsigned long delta_exec)
 {
-   unsigned long delta, delta_exec, delta_fair, delta_mine;
-   struct load_weight *lw = &cfs_rq->load;
-   unsigned long load = lw->weight;
+   unsigned long delta_exec_weighted;
+   u64 vruntime;
 
-   delta_exec = curr->delta_exec;
    schedstat_set(curr->exec_max, max((u64)delta_exec, curr->exec_max));
 
    curr->sum_exec_runtime += delta_exec;
-   cfs_rq->exec_clock += delta_exec;
-
-   if (unlikely(!load))
-      return;
-
-   delta_fair = calc_delta_fair(delta_exec, lw);
-   delta_mine = calc_delta_mine(delta_exec, curr->load.weight, lw);
-
-   if (cfs_rq->sleeper_bonus > sysctl_sched_min_granularity) {
-      delta = min((u64)delta_mine, cfs_rq->sleeper_bonus);
-      delta = min(delta, (unsigned long)(
-         (long)sysctl_sched_runtime_limit - curr->wait_runtime));
-      cfs_rq->sleeper_bonus -= delta;
-      delta_mine -= delta;
+   schedstat_add(cfs_rq, exec_clock, delta_exec);
+   delta_exec_weighted = delta_exec;
+   if (unlikely(curr->load.weight != NICE_0_LOAD)) {
+      delta_exec_weighted = calc_delta_fair(delta_exec_weighted,
+                     &curr->load);
    }
+   curr->vruntime += delta_exec_weighted;
 
-   cfs_rq->fair_clock += delta_fair;
    /*
-    * We executed delta_exec amount of time on the CPU,
-    * but we were only entitled to delta_mine amount of
-    * time during that period (if nr_running == 1 then
-    * the two values are equal)
-    * [Note: delta_mine - delta_exec is negative]:
+    * maintain cfs_rq->min_vruntime to be a monotonic increasing
+    * value tracking the leftmost vruntime in the tree.
     */
-   add_wait_runtime(cfs_rq, curr, delta_mine - delta_exec);
+   if (first_fair(cfs_rq)) {
+      vruntime = min_vruntime(curr->vruntime,
+            __pick_next_entity(cfs_rq)->vruntime);
+   } else
+      vruntime = curr->vruntime;
+
+   cfs_rq->min_vruntime =
+      max_vruntime(cfs_rq->min_vruntime, vruntime);
 }
 
 static void update_curr(struct cfs_rq *cfs_rq)
 {
-   struct sched_entity *curr = cfs_rq_curr(cfs_rq);
+   struct sched_entity *curr = cfs_rq->curr;
+   u64 now = rq_of(cfs_rq)->clock;
    unsigned long delta_exec;
 
    if (unlikely(!curr))
@@ -398,135 +347,53 @@ static void update_curr(struct cfs_rq *cfs_rq)
     * since the last time we changed load (this cannot
     * overflow on 32 bits):
     */
-   delta_exec = (unsigned long)(rq_of(cfs_rq)->clock - curr->exec_start);
+   delta_exec = (unsigned long)(now - curr->exec_start);
 
-   curr->delta_exec += delta_exec;
+   __update_curr(cfs_rq, curr, delta_exec);
+   curr->exec_start = now;
 
-   if (unlikely(curr->delta_exec > sysctl_sched_stat_granularity)) {
-      __update_curr(cfs_rq, curr);
-      curr->delta_exec = 0;
+   if (entity_is_task(curr)) {
+      struct task_struct *curtask = task_of(curr);
+
+      cpuacct_charge(curtask, delta_exec);
    }
-   curr->exec_start = rq_of(cfs_rq)->clock;
 }
 
 static inline void
 update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   se->wait_start_fair = cfs_rq->fair_clock;
    schedstat_set(se->wait_start, rq_of(cfs_rq)->clock);
 }
 
 /*
- * We calculate fair deltas here, so protect against the random effects
- * of a multiplication overflow by capping it to the runtime limit:
- */
-#if BITS_PER_LONG == 32
-static inline unsigned long
-calc_weighted(unsigned long delta, unsigned long weight, int shift)
-{
-   u64 tmp = (u64)delta * weight >> shift;
-
-   if (unlikely(tmp > sysctl_sched_runtime_limit*2))
-      return sysctl_sched_runtime_limit*2;
-   return tmp;
-}
-#else
-static inline unsigned long
-calc_weighted(unsigned long delta, unsigned long weight, int shift)
-{
-   return delta * weight >> shift;
-}
-#endif
-
-/*
  * Task is being enqueued - update stats:
  */
 static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   s64 key;
-
    /*
     * Are we enqueueing a waiting task? (for current tasks
     * a dequeue/enqueue event is a NOP)
     */
-   if (se != cfs_rq_curr(cfs_rq))
+   if (se != cfs_rq->curr)
       update_stats_wait_start(cfs_rq, se);
-   /*
-    * Update the key:
-    */
-   key = cfs_rq->fair_clock;
-
-   /*
-    * Optimize the common nice 0 case:
-    */
-   if (likely(se->load.weight == NICE_0_LOAD)) {
-      key -= se->wait_runtime;
-   } else {
-      u64 tmp;
-
-      if (se->wait_runtime < 0) {
-         tmp = -se->wait_runtime;
-         key += (tmp * se->load.inv_weight) >>
-               (WMULT_SHIFT - NICE_0_SHIFT);
-      } else {
-         tmp = se->wait_runtime;
-         key -= (tmp * se->load.inv_weight) >>
-               (WMULT_SHIFT - NICE_0_SHIFT);
-      }
-   }
-
-   se->fair_key = key;
-}
-
-/*
- * Note: must be called with a freshly updated rq->fair_clock.
- */
-static inline void
-__update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-   unsigned long delta_fair = se->delta_fair_run;
-
-   schedstat_set(se->wait_max, max(se->wait_max,
-         rq_of(cfs_rq)->clock - se->wait_start));
-
-   if (unlikely(se->load.weight != NICE_0_LOAD))
-      delta_fair = calc_weighted(delta_fair, se->load.weight,
-                     NICE_0_SHIFT);
-
-   add_wait_runtime(cfs_rq, se, delta_fair);
 }
 
 static void
 update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   unsigned long delta_fair;
-
-   if (unlikely(!se->wait_start_fair))
-      return;
-
-   delta_fair = (unsigned long)min((u64)(2*sysctl_sched_runtime_limit),
-         (u64)(cfs_rq->fair_clock - se->wait_start_fair));
-
-   se->delta_fair_run += delta_fair;
-   if (unlikely(abs(se->delta_fair_run) >=
-            sysctl_sched_stat_granularity)) {
-      __update_stats_wait_end(cfs_rq, se);
-      se->delta_fair_run = 0;
-   }
-
-   se->wait_start_fair = 0;
+   schedstat_set(se->wait_max, max(se->wait_max,
+         rq_of(cfs_rq)->clock - se->wait_start));
    schedstat_set(se->wait_start, 0);
 }
 
 static inline void
 update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   update_curr(cfs_rq);
    /*
     * Mark the end of the wait period if dequeueing a
     * waiting task:
     */
-   if (se != cfs_rq_curr(cfs_rq))
+   if (se != cfs_rq->curr)
       update_stats_wait_end(cfs_rq, se);
 }
 
@@ -542,79 +409,28 @@ 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:
  */
 
-static void __enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void
+account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   unsigned long load = cfs_rq->load.weight, delta_fair;
-   long prev_runtime;
-
-   /*
-    * Do not boost sleepers if there's too much bonus 'in flight'
-    * already:
-    */
-   if (unlikely(cfs_rq->sleeper_bonus > sysctl_sched_runtime_limit))
-      return;
-
-   if (sysctl_sched_features & SCHED_FEAT_SLEEPER_LOAD_AVG)
-      load = rq_of(cfs_rq)->cpu_load[2];
-
-   delta_fair = se->delta_fair_sleep;
-
-   /*
-    * Fix up delta_fair with the effect of us running
-    * during the whole sleep period:
-    */
-   if (sysctl_sched_features & SCHED_FEAT_SLEEPER_AVG)
-      delta_fair = div64_likely32((u64)delta_fair * load,
-                  load + se->load.weight);
-
-   if (unlikely(se->load.weight != NICE_0_LOAD))
-      delta_fair = calc_weighted(delta_fair, se->load.weight,
-                     NICE_0_SHIFT);
-
-   prev_runtime = se->wait_runtime;
-   __add_wait_runtime(cfs_rq, se, delta_fair);
-   delta_fair = se->wait_runtime - prev_runtime;
+   update_load_add(&cfs_rq->load, se->load.weight);
+   cfs_rq->nr_running++;
+   se->on_rq = 1;
+}
 
-   /*
-    * Track the amount of bonus we've given to sleepers:
-    */
-   cfs_rq->sleeper_bonus += delta_fair;
+static void
+account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+   update_load_sub(&cfs_rq->load, se->load.weight);
+   cfs_rq->nr_running--;
+   se->on_rq = 0;
 }
 
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-   struct task_struct *tsk = task_of(se);
-   unsigned long delta_fair;
-
-   if ((entity_is_task(se) && tsk->policy == SCHED_BATCH) ||
-          !(sysctl_sched_features & SCHED_FEAT_FAIR_SLEEPERS))
-      return;
-
-   delta_fair = (unsigned long)min((u64)(2*sysctl_sched_runtime_limit),
-      (u64)(cfs_rq->fair_clock - se->sleep_start_fair));
-
-   se->delta_fair_sleep += delta_fair;
-   if (unlikely(abs(se->delta_fair_sleep) >=
-            sysctl_sched_stat_granularity)) {
-      __enqueue_sleeper(cfs_rq, se);
-      se->delta_fair_sleep = 0;
-   }
-
-   se->sleep_start_fair = 0;
-
 #ifdef CONFIG_SCHEDSTATS
    if (se->sleep_start) {
       u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
@@ -646,6 +462,8 @@ 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);
       }
@@ -653,27 +471,86 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 #endif
 }
 
+static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+#ifdef CONFIG_SCHED_DEBUG
+   s64 d = se->vruntime - cfs_rq->min_vruntime;
+
+   if (d < 0)
+      d = -d;
+
+   if (d > 3*sysctl_sched_latency)
+      schedstat_inc(cfs_rq, nr_spread_over);
+#endif
+}
+
+static void
+place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
+{
+   u64 vruntime;
+
+   vruntime = cfs_rq->min_vruntime;
+
+   if (sched_feat(TREE_AVG)) {
+      struct sched_entity *last = __pick_last_entity(cfs_rq);
+      if (last) {
+         vruntime += last->vruntime;
+         vruntime >>= 1;
+      }
+   } 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) && entity_is_task(se))
+         vruntime -= sysctl_sched_latency;
+
+      /* ensure we never gain time by being placed backwards. */
+      vruntime = max_vruntime(se->vruntime, vruntime);
+   }
+
+   se->vruntime = vruntime;
+}
+
 static void
 enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
 {
    /*
-    * Update the fair clock.
+    * Update run-time statistics of the 'current'.
     */
    update_curr(cfs_rq);
 
-   if (wakeup)
+   if (wakeup) {
+      place_entity(cfs_rq, se, 0);
       enqueue_sleeper(cfs_rq, se);
+   }
 
    update_stats_enqueue(cfs_rq, se);
-   __enqueue_entity(cfs_rq, se);
+   check_spread(cfs_rq, se);
+   if (se != cfs_rq->curr)
+      __enqueue_entity(cfs_rq, se);
+   account_entity_enqueue(cfs_rq, se);
 }
 
 static void
 dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 {
+   /*
+    * Update run-time statistics of the 'current'.
+    */
+   update_curr(cfs_rq);
+
    update_stats_dequeue(cfs_rq, se);
    if (sleep) {
-      se->sleep_start_fair = cfs_rq->fair_clock;
 #ifdef CONFIG_SCHEDSTATS
       if (entity_is_task(se)) {
          struct task_struct *tsk = task_of(se);
@@ -685,68 +562,64 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
       }
 #endif
    }
-   __dequeue_entity(cfs_rq, se);
+
+   if (se != cfs_rq->curr)
+      __dequeue_entity(cfs_rq, se);
+   account_entity_dequeue(cfs_rq, se);
 }
 
 /*
  * Preempt the current task with a newly woken task if needed:
  */
 static void
-__check_preempt_curr_fair(struct cfs_rq *cfs_rq, struct sched_entity *se,
-           struct sched_entity *curr, unsigned long granularity)
+check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 {
-   s64 __delta = curr->fair_key - se->fair_key;
    unsigned long ideal_runtime, delta_exec;
 
-   /*
-    * ideal_runtime is compared against sum_exec_runtime, which is
-    * walltime, hence do not scale.
-    */
-   ideal_runtime = max(sysctl_sched_latency / cfs_rq->nr_running,
-         (unsigned long)sysctl_sched_min_granularity);
-
-   /*
-    * If we executed more than what the latency constraint suggests,
-    * reduce the rescheduling granularity. This way the total latency
-    * of how much a task is not scheduled converges to
-    * sysctl_sched_latency:
-    */
+   ideal_runtime = sched_slice(cfs_rq, curr);
    delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
    if (delta_exec > ideal_runtime)
-      granularity = 0;
-
-   /*
-    * Take scheduling granularity into account - do not
-    * preempt the current task unless the best task has
-    * a larger than sched_granularity fairness advantage:
-    *
-    * scale granularity as key space is in fair_clock.
-    */
-   if (__delta > niced_granularity(curr, granularity))
       resched_task(rq_of(cfs_rq)->curr);
 }
 
-static inline void
+static void
 set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
+   /* 'current' is not kept within the tree. */
+   if (se->on_rq) {
+      /*
+       * Any task has to be enqueued before it get to execute on
+       * a CPU. So account for the time it spent waiting on the
+       * runqueue.
+       */
+      update_stats_wait_end(cfs_rq, se);
+      __dequeue_entity(cfs_rq, se);
+   }
+
+   update_stats_curr_start(cfs_rq, se);
+   cfs_rq->curr = se;
+#ifdef CONFIG_SCHEDSTATS
    /*
-    * Any task has to be enqueued before it get to execute on
-    * a CPU. So account for the time it spent waiting on the
-    * runqueue. (note, here we rely on pick_next_task() having
-    * done a put_prev_task_fair() shortly before this, which
-    * updated rq->fair_clock - used by update_stats_wait_end())
+    * Track our maximum slice length, if the CPU's load is at
+    * least twice that of our own weight (i.e. dont track it
+    * when there are only lesser-weight tasks around):
     */
-   update_stats_wait_end(cfs_rq, se);
-   update_stats_curr_start(cfs_rq, se);
-   set_cfs_rq_curr(cfs_rq, se);
+   if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
+      se->slice_max = max(se->slice_max,
+         se->sum_exec_runtime - se->prev_sum_exec_runtime);
+   }
+#endif
    se->prev_sum_exec_runtime = se->sum_exec_runtime;
 }
 
 static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
 {
-   struct sched_entity *se = __pick_next_entity(cfs_rq);
+   struct sched_entity *se = NULL;
 
-   set_next_entity(cfs_rq, se);
+   if (first_fair(cfs_rq)) {
+      se = __pick_next_entity(cfs_rq);
+      set_next_entity(cfs_rq, se);
+   }
 
    return se;
 }
@@ -760,33 +633,24 @@ 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);
-
-   if (prev->on_rq)
+   check_spread(cfs_rq, prev);
+   if (prev->on_rq) {
       update_stats_wait_start(cfs_rq, prev);
-   set_cfs_rq_curr(cfs_rq, NULL);
+      /* Put 'current' back into the tree. */
+      __enqueue_entity(cfs_rq, prev);
+   }
+   cfs_rq->curr = NULL;
 }
 
 static void entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 {
-   struct sched_entity *next;
-
    /*
-    * Dequeue and enqueue the task to update its
-    * position within the tree:
+    * Update run-time statistics of the 'current'.
     */
-   dequeue_entity(cfs_rq, curr, 0);
-   enqueue_entity(cfs_rq, curr, 0);
-
-   /*
-    * Reschedule if another task tops the current one.
-    */
-   next = __pick_next_entity(cfs_rq);
-   if (next == curr)
-      return;
+   update_curr(cfs_rq);
 
-   __check_preempt_curr_fair(cfs_rq, next, curr,
-         sched_granularity(cfs_rq));
+   if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT))
+      check_preempt_tick(cfs_rq, curr);
 }
 
 /**************************************************
@@ -821,23 +685,28 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
  */
 static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
 {
-   /* A later patch will take group into account */
-   return &cpu_rq(this_cpu)->cfs;
+   return cfs_rq->tg->cfs_rq[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)
 
-/* Do the two (enqueued) tasks belong to the same group ? */
-static inline int is_same_group(struct task_struct *curr, struct task_struct *p)
+/* Do the two (enqueued) entities belong to the same group ? */
+static inline int
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
 {
-   if (curr->se.cfs_rq == p->se.cfs_rq)
+   if (se->cfs_rq == pse->cfs_rq)
       return 1;
 
    return 0;
 }
 
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+   return se->parent;
+}
+
 #else   /* CONFIG_FAIR_GROUP_SCHED */
 
 #define for_each_sched_entity(se) \
@@ -870,11 +739,17 @@ static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
 #define for_each_leaf_cfs_rq(rq, cfs_rq) \
       for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL)
 
-static inline int is_same_group(struct task_struct *curr, struct task_struct *p)
+static inline int
+is_same_group(struct sched_entity *se, struct sched_entity *pse)
 {
    return 1;
 }
 
+static inline struct sched_entity *parent_entity(struct sched_entity *se)
+{
+   return NULL;
+}
+
 #endif   /* CONFIG_FAIR_GROUP_SCHED */
 
 /*
@@ -892,6 +767,7 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
          break;
       cfs_rq = cfs_rq_of(se);
       enqueue_entity(cfs_rq, se, wakeup);
+      wakeup = 1;
    }
 }
 
@@ -911,6 +787,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
       /* Don't dequeue parent if it has other entities besides us */
       if (cfs_rq->load.weight)
          break;
+      sleep = 1;
    }
 }
 
@@ -919,12 +796,11 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
  *
  * If compat_yield is turned on then we requeue to the end of the tree.
  */
-static void yield_task_fair(struct rq *rq, struct task_struct *p)
+static void yield_task_fair(struct rq *rq)
 {
-   struct cfs_rq *cfs_rq = task_cfs_rq(p);
-   struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
-   struct sched_entity *rightmost, *se = &p->se;
-   struct rb_node *parent;
+   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?
@@ -932,54 +808,41 @@ static void yield_task_fair(struct rq *rq, struct task_struct *p)
    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);
       /*
-       * Dequeue and enqueue the task to update its
-       * position within the tree:
+       * Update run-time statistics of the 'current'.
        */
-      dequeue_entity(cfs_rq, &p->se, 0);
-      enqueue_entity(cfs_rq, &p->se, 0);
+      update_curr(cfs_rq);
 
       return;
    }
    /*
     * Find the rightmost entry in the rbtree:
     */
-   do {
-      parent = *link;
-      link = &parent->rb_right;
-   } while (*link);
-
-   rightmost = rb_entry(parent, struct sched_entity, run_node);
+   rightmost = __pick_last_entity(cfs_rq);
    /*
     * Already in the rightmost position?
     */
-   if (unlikely(rightmost == se))
+   if (unlikely(rightmost->vruntime < se->vruntime))
       return;
 
    /*
     * Minimally necessary key value to be last in the tree:
+    * Upon rescheduling, sched_class::put_prev_task() will place
+    * 'current' within the tree based on its new key value.
     */
-   se->fair_key = rightmost->fair_key + 1;
-
-   if (cfs_rq->rb_leftmost == &se->run_node)
-      cfs_rq->rb_leftmost = rb_next(&se->run_node);
-   /*
-    * Relink the task to the rightmost position:
-    */
-   rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
-   rb_link_node(&se->run_node, parent, link);
-   rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline);
+   se->vruntime = rightmost->vruntime + 1;
 }
 
 /*
  * Preempt the current task with a newly woken task if needed:
  */
-static void check_preempt_curr_fair(struct rq *rq, struct task_struct *p)
+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;
    unsigned long gran;
 
    if (unlikely(rt_prio(p->prio))) {
@@ -988,16 +851,27 @@ static void check_preempt_curr_fair(struct rq *rq, struct task_struct *p)
       resched_task(curr);
       return;
    }
-
-   gran = sysctl_sched_wakeup_granularity;
    /*
-    * Batch tasks prefer throughput over latency:
+    * Batch tasks do not preempt (their preemption is driven by
+    * the tick):
     */
    if (unlikely(p->policy == SCHED_BATCH))
-      gran = sysctl_sched_batch_wakeup_granularity;
+      return;
 
-   if (is_same_group(curr, p))
-      __check_preempt_curr_fair(cfs_rq, &p->se, &curr->se, gran);
+   if (!sched_feat(WAKEUP_PREEMPT))
+      return;
+
+   while (!is_same_group(se, pse)) {
+      se = parent_entity(se);
+      pse = parent_entity(pse);
+   }
+
+   gran = sysctl_sched_wakeup_granularity;
+   if (unlikely(se->load.weight != NICE_0_LOAD))
+      gran = calc_delta_fair(gran, &se->load);
+
+   if (pse->vruntime + gran < se->vruntime)
+      resched_task(curr);
 }
 
 static struct task_struct *pick_next_task_fair(struct rq *rq)
@@ -1030,6 +904,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
    }
 }
 
+#ifdef CONFIG_SMP
 /**************************************************
  * Fair scheduling class load-balancing methods:
  */
@@ -1041,7 +916,7 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
  * achieve that by always pre-iterating before returning
  * the current task:
  */
-static inline struct task_struct *
+static struct task_struct *
 __load_balance_iterator(struct cfs_rq *cfs_rq, struct rb_node *curr)
 {
    struct task_struct *p;
@@ -1078,7 +953,10 @@ static int cfs_rq_best_prio(struct cfs_rq *cfs_rq)
    if (!cfs_rq->nr_running)
       return MAX_PRIO;
 
-   curr = __pick_next_entity(cfs_rq);
+   curr = cfs_rq->curr;
+   if (!curr)
+      curr = __pick_next_entity(cfs_rq);
+
    p = task_of(curr);
 
    return p->prio;
@@ -1087,12 +965,11 @@ 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;
 
@@ -1120,25 +997,48 @@ 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);
-
-      total_nr_moved += nr_moved;
-      max_nr_move -= nr_moved;
-      rem_load_move -= load_moved;
+      rem_load_move -= balance_tasks(this_rq, this_cpu, busiest,
+                      maxload, sd, idle, all_pinned,
+                      this_best_prio,
+                      &cfs_rq_iterator);
 
-      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:
  */
@@ -1153,6 +1053,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr)
    }
 }
 
+#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
  * total amount of pressure for CPU stays equal - new tasks
@@ -1163,37 +1065,28 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr)
 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(cfs_rq);
+   struct sched_entity *se = &p->se, *curr = cfs_rq->curr;
+   int this_cpu = smp_processor_id();
 
    sched_info_queued(p);
 
    update_curr(cfs_rq);
-   update_stats_enqueue(cfs_rq, se);
-   /*
-    * Child runs first: we let it run before the parent
-    * until it reschedules once. We set up the key so that
-    * it will preempt the parent:
-    */
-   se->fair_key = curr->fair_key -
-      niced_granularity(curr, sched_granularity(cfs_rq)) - 1;
-   /*
-    * The first wait is dominated by the child-runs-first logic,
-    * so do not credit it with that waiting time yet:
-    */
-   if (sysctl_sched_features & SCHED_FEAT_SKIP_INITIAL)
-      se->wait_start_fair = 0;
+   place_entity(cfs_rq, se, 1);
 
-   /*
-    * The statistical average of wait_runtime is about
-    * -granularity/2, so initialize the task with that:
-    */
-   if (sysctl_sched_features & SCHED_FEAT_START_DEBIT)
-      se->wait_runtime = -(sched_granularity(cfs_rq) / 2);
+   /* '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.
+       */
+      swap(curr->vruntime, se->vruntime);
+   }
 
-   __enqueue_entity(cfs_rq, se);
+   enqueue_task_fair(rq, p, 0);
+   resched_task(rq->curr);
 }
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
 /* Account for a task changing its policy or group.
  *
  * This routine is mostly called to set cfs_rq->curr field when a task
@@ -1206,26 +1099,25 @@ static void set_curr_task_fair(struct rq *rq)
    for_each_sched_entity(se)
       set_next_entity(cfs_rq_of(se), se);
 }
-#else
-static void set_curr_task_fair(struct rq *rq)
-{
-}
-#endif
 
 /*
  * All the scheduling class methods:
  */
-struct sched_class fair_sched_class __read_mostly = {
+static const struct sched_class fair_sched_class = {
+   .next         = &idle_sched_class,
    .enqueue_task      = enqueue_task_fair,
    .dequeue_task      = dequeue_task_fair,
    .yield_task      = yield_task_fair,
 
-   .check_preempt_curr   = check_preempt_curr_fair,
+   .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,
@@ -1237,6 +1129,9 @@ static void print_cfs_stats(struct seq_file *m, int cpu)
 {
    struct cfs_rq *cfs_rq;
 
+#ifdef CONFIG_FAIR_GROUP_SCHED
+   print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs);
+#endif
    for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
       print_cfs_rq(m, cpu, cfs_rq);
 }