sched/fair: Init cfs_rq's sched_entity load average

The runnable load and utilization averages of cfs_rq's sched_entity
were not initiated. Like done to a task, give new cfs_rq' sched_entity
start values to heavy its load in infant time.

Signed-off-by: Yuyang Du <yuyang.du@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arjan@linux.intel.com
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: fengguang.wu@intel.com
Cc: len.brown@intel.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: rafael.j.wysocki@intel.com
Cc: umgwanakikbuti@gmail.com
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/1436918682-4971-5-git-send-email-yuyang.du@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -2304,7 +2304,7 @@ void wake_up_new_task(struct task_struct *p)
 #endif
 
 	/* Initialize new task's runnable average */
-	init_task_runnable_average(p);
+	init_entity_runnable_average(&p->se);
 	rq = __task_rq_lock(p);
 	activate_task(rq, p, 0);
 	p->on_rq = TASK_ON_RQ_QUEUED;

kernel/sched/fair.c

@@ -667,10 +667,10 @@ static unsigned long task_h_load(struct task_struct *p);
 #define LOAD_AVG_MAX 47742 /* maximum possible load avg */
 #define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_MAX_AVG */
 
-/* Give new task start runnable values to heavy its load in infant time */
-void init_task_runnable_average(struct task_struct *p)
+/* Give new sched_entity start runnable values to heavy its load in infant time */
+void init_entity_runnable_average(struct sched_entity *se)
 {
-	struct sched_avg *sa = &p->se.avg;
+	struct sched_avg *sa = &se->avg;
 
 	sa->last_update_time = 0;
 	/*
@@ -679,14 +679,14 @@ void init_task_runnable_average(struct task_struct *p)
 	 * will definitely be update (after enqueue).
 	 */
 	sa->period_contrib = 1023;
-	sa->load_avg = scale_load_down(p->se.load.weight);
+	sa->load_avg = scale_load_down(se->load.weight);
 	sa->load_sum = sa->load_avg * LOAD_AVG_MAX;
 	sa->util_avg = scale_load_down(SCHED_LOAD_SCALE);
 	sa->util_sum = LOAD_AVG_MAX;
 	/* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
 }
 #else
-void init_task_runnable_average(struct task_struct *p)
+void init_entity_runnable_average(struct sched_entity *se)
 {
 }
 #endif
@@ -8029,6 +8029,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
 
 		init_cfs_rq(cfs_rq);
 		init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
+		init_entity_runnable_average(se);
 	}
 
 	return 1;

kernel/sched/sched.h

@@ -1307,7 +1307,7 @@ extern void init_dl_task_timer(struct sched_dl_entity *dl_se);
 
 unsigned long to_ratio(u64 period, u64 runtime);
 
-extern void init_task_runnable_average(struct task_struct *p);
+extern void init_entity_runnable_average(struct sched_entity *se);
 
 static inline void add_nr_running(struct rq *rq, unsigned count)
 {