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sched/fair: Reorder cgroup creation code 

A future patch needs rq->lock held _after_ we link the task_group into
the hierarchy. In order to avoid taking every rq->lock twice, reorder
things a little and create online_fair_sched_group() to be called
after we link the task_group.

All this code is still ran from css_alloc() so css_online() isn't in
fact used for this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
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: bsegall@google.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-06-22 14:58:02 +02:00 committed by Ingo Molnar
parent 3d30544f02
commit 8663e24d56
3 changed files with 21 additions and 4 deletions
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2
kernel/sched/core.c
View File

@ -7717,6 +7717,8 @@ void sched_online_group(struct task_group *tg, struct task_group *parent)
INIT_LIST_HEAD(&tg->children);
list_add_rcu(&tg->siblings, &parent->children);
spin_unlock_irqrestore(&task_group_lock, flags);
online_fair_sched_group(tg);
}
/* rcu callback to free various structures associated with a task group */

22
kernel/sched/fair.c
View File

@ -8624,10 +8624,6 @@ 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);
raw_spin_lock_irq(&rq->lock);
post_init_entity_util_avg(se);
raw_spin_unlock_irq(&rq->lock);
}
return 1;
@ -8638,6 +8634,22 @@ err:
return 0;
}
void online_fair_sched_group(struct task_group *tg)
{
struct sched_entity *se;
struct rq *rq;
int i;
for_each_possible_cpu(i) {
rq = cpu_rq(i);
se = tg->se[i];
raw_spin_lock_irq(&rq->lock);
post_init_entity_util_avg(se);
raw_spin_unlock_irq(&rq->lock);
}
}
void unregister_fair_sched_group(struct task_group *tg)
{
unsigned long flags;
@ -8742,6 +8754,8 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
return 1;
}
void online_fair_sched_group(struct task_group *tg) { }
void unregister_fair_sched_group(struct task_group *tg) { }
#endif /* CONFIG_FAIR_GROUP_SCHED */

1
kernel/sched/sched.h
View File

@ -321,6 +321,7 @@ extern int tg_nop(struct task_group *tg, void *data);
extern void free_fair_sched_group(struct task_group *tg);
extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
extern void online_fair_sched_group(struct task_group *tg);
extern void unregister_fair_sched_group(struct task_group *tg);
extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
struct sched_entity *se, int cpu,