[PATCH v7 2/4] sched/fair: Move load and util avgs from wake_up_new_task() to sched_fork()

[Yuyang Du]

Move new task initialization to sched_fork(). For initial non-fair class
task, the first switched_to_fair() will do the attach correctly.

Suggested-by: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Yuyang Du <yuyang...@intel.com>
---
 kernel/sched/core.c  |    5 +++--
 kernel/sched/fair.c  |   14 +++++---------
 kernel/sched/sched.h |    2 +-
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 31c30e5..6b7d0b1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2384,6 +2384,9 @@ int sched_fork(unsigned long clone_flags, struct 
task_struct *p)
        if (p->sched_class->task_fork)
                p->sched_class->task_fork(p);
 
+       /* Initialize new task's sched averages */
+       init_entity_sched_avg(&p->se);
+
        /*
         * The child is not yet in the pid-hash so no cgroup attach races,
         * and the cgroup is pinned to this child due to cgroup_fork()
@@ -2524,8 +2527,6 @@ void wake_up_new_task(struct task_struct *p)
        struct rq_flags rf;
        struct rq *rq;
 
-       /* Initialize new task's runnable average */
-       init_entity_runnable_average(&p->se);
        raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
 #ifdef CONFIG_SMP
        /*
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d43d242..35d76cf 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -668,8 +668,8 @@ 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_AVG_MAX */
 
-/* Give new sched_entity start runnable values to heavy its load in infant 
time */
-void init_entity_runnable_average(struct sched_entity *se)
+/* Give new sched_entity start load values to heavy its load in infant time */
+void init_entity_sched_avg(struct sched_entity *se)
 {
        struct sched_avg *sa = &se->avg;
 
@@ -738,12 +738,8 @@ void post_init_entity_util_avg(struct sched_entity *se)
 static inline unsigned long cfs_rq_runnable_load_avg(struct cfs_rq *cfs_rq);
 static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq);
 #else
-void init_entity_runnable_average(struct sched_entity *se)
-{
-}
-void post_init_entity_util_avg(struct sched_entity *se)
-{
-}
+void init_entity_sched_avg(struct sched_entity *se) { }
+void post_init_entity_util_avg(struct sched_entity *se) { }
 #endif
 
 /*
@@ -8527,7 +8523,7 @@ 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);
+               init_entity_sched_avg(se);
 
                raw_spin_lock_irq(&rq->lock);
                post_init_entity_util_avg(se);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index bf6fea9..1b1d439 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1321,7 +1321,7 @@ extern void init_dl_task_timer(struct sched_dl_entity 
*dl_se);
 
 unsigned long to_ratio(u64 period, u64 runtime);
 
-extern void init_entity_runnable_average(struct sched_entity *se);
+extern void init_entity_sched_avg(struct sched_entity *se);
 extern void post_init_entity_util_avg(struct sched_entity *se);
 
 #ifdef CONFIG_NO_HZ_FULL
-- 
1.7.9.5