From 8663e24d56dc1f093232783c23ea17f2a6f61c03 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 22 Jun 2016 14:58:02 +0200 Subject: [PATCH] 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) Cc: Konstantin Khlebnikov Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bsegall@google.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 2 ++ kernel/sched/fair.c | 22 ++++++++++++++++++---- kernel/sched/sched.h | 1 + 3 files changed, 21 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 14afa518948c..4ede4fc65653 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -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 */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 781788d54736..62d5e7dcc7f8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -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 */ diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 307bd0418095..28c42b789f70 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -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,