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sched/fair: Avoid calling sync_entity_load_avg() unnecessarily 

Call sync_entity_load_avg() directly from find_idlest_cpu() instead of
select_task_rq_fair(), as that's where we need to use task's utilization
value. And call sync_entity_load_avg() only after making sure sched
domain spans over one of the allowed CPUs for the task.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: http://lkml.kernel.org/r/cd019d1753824c81130eae7b43e2bbcec47cc1ad.1524738578.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Viresh Kumar 2018-04-26 16:00:51 +05:30 committed by Ingo Molnar
parent f1d88b4468
commit c976a862ba
1 changed files with 7 additions and 9 deletions
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16
kernel/sched/fair.c
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@ -6199,6 +6199,13 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
if (!cpumask_intersects(sched_domain_span(sd), &p->cpus_allowed))
return prev_cpu;
/*
* We need task's util for capacity_spare_wake, sync it up to prev_cpu's
* last_update_time.
*/
if (!(sd_flag & SD_BALANCE_FORK))
sync_entity_load_avg(&p->se);
while (sd) {
struct sched_group *group;
struct sched_domain *tmp;
@ -6651,15 +6658,6 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (unlikely(sd)) {
/* Slow path */
/*
* We're going to need the task's util for capacity_spare_wake
* in find_idlest_group. Sync it up to prev_cpu's
* last_update_time.
*/
if (!(sd_flag & SD_BALANCE_FORK))
sync_entity_load_avg(&p->se);
new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
} else if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */
/* Fast path */