3 files changed, 28 insertions, 4 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0241b1b55a04..729e7fc7634b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1611,10 +1611,6 @@ static void __sched_fork(struct task_struct *p)
         p->se.vruntime                  = 0;
         INIT_LIST_HEAD(&p->se.group_node);
 
-#ifdef CONFIG_SMP
-        p->se.avg.runnable_avg_period = 0;
-        p->se.avg.runnable_avg_sum = 0;
-#endif
 #ifdef CONFIG_SCHEDSTATS
         memset(&p->se.statistics, 0, sizeof(p->se.statistics));
 #endif
@@ -1758,6 +1754,8 @@ void wake_up_new_task(struct task_struct *p)
         set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
 #endif
 
+        /* Initialize new task's runnable average */
+        init_task_runnable_average(p);
         rq = __task_rq_lock(p);
         activate_task(rq, p, 0);
         p->on_rq = 1;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 36eadaaa4e5b..e1602a0fdbf8 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -680,6 +680,26 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
         return calc_delta_fair(sched_slice(cfs_rq, se), se);
 }
 
+#ifdef CONFIG_SMP
+static inline void __update_task_entity_contrib(struct sched_entity *se);
+
+/* Give new task start runnable values to heavy its load in infant time */
+void init_task_runnable_average(struct task_struct *p)
+{
+        u32 slice;
+
+        p->se.avg.decay_count = 0;
+        slice = sched_slice(task_cfs_rq(p), &p->se) >> 10;
+        p->se.avg.runnable_avg_sum = slice;
+        p->se.avg.runnable_avg_period = slice;
+        __update_task_entity_contrib(&p->se);
+}
+#else
+void init_task_runnable_average(struct task_struct *p)
+{
+}
+#endif
+
 /*
  * Update the current task's runtime statistics. Skip current tasks that
  * are not in our scheduling class.
@@ -1527,6 +1547,10 @@ static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq,
          * We track migrations using entity decay_count <= 0, on a wake-up
          * migration we use a negative decay count to track the remote decays
          * accumulated while sleeping.
+         *
+         * Newly forked tasks are enqueued with se->avg.decay_count == 0, they
+         * are seen by enqueue_entity_load_avg() as a migration with an already
+         * constructed load_avg_contrib.
          */
         if (unlikely(se->avg.decay_count <= 0)) {
                 se->avg.last_runnable_update = rq_clock_task(rq_of(cfs_rq));
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 31d25f80a7c6..9c65d46504b1 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1048,6 +1048,8 @@ extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime
 
 extern void update_idle_cpu_load(struct rq *this_rq);
 
+extern void init_task_runnable_average(struct task_struct *p);
+
 #ifdef CONFIG_PARAVIRT
 static inline u64 steal_ticks(u64 steal)
 {