From 6fe1f348b3dd1f700f9630562b7d38afd6949568 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 21 Jan 2016 22:24:16 +0100 Subject: sched/cgroup: Fix cgroup entity load tracking tear-down When a cgroup's CPU runqueue is destroyed, it should remove its remaining load accounting from its parent cgroup. The current site for doing so it unsuited because its far too late and unordered against other cgroup removal (->css_free() will be, but we're also in an RCU callback). Put it in the ->css_offline() callback, which is the start of cgroup destruction, right after the group has been made unavailable to userspace. The ->css_offline() callbacks are called in hierarchical order after the following v4.4 commit: aa226ff4a1ce ("cgroup: make sure a parent css isn't offlined before its children") Signed-off-by: Peter Zijlstra (Intel) Cc: Christian Borntraeger Cc: Johannes Weiner Cc: Li Zefan Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20160121212416.GL6357@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) (limited to 'kernel/sched/fair.c') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 56b7d4b..cce3303 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8234,11 +8234,8 @@ void free_fair_sched_group(struct task_group *tg) for_each_possible_cpu(i) { if (tg->cfs_rq) kfree(tg->cfs_rq[i]); - if (tg->se) { - if (tg->se[i]) - remove_entity_load_avg(tg->se[i]); + if (tg->se) kfree(tg->se[i]); - } } kfree(tg->cfs_rq); @@ -8286,21 +8283,29 @@ err: return 0; } -void unregister_fair_sched_group(struct task_group *tg, int cpu) +void unregister_fair_sched_group(struct task_group *tg) { - struct rq *rq = cpu_rq(cpu); unsigned long flags; + struct rq *rq; + int cpu; - /* - * Only empty task groups can be destroyed; so we can speculatively - * check on_list without danger of it being re-added. - */ - if (!tg->cfs_rq[cpu]->on_list) - return; + for_each_possible_cpu(cpu) { + if (tg->se[cpu]) + remove_entity_load_avg(tg->se[cpu]); - raw_spin_lock_irqsave(&rq->lock, flags); - list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); - raw_spin_unlock_irqrestore(&rq->lock, flags); + /* + * Only empty task groups can be destroyed; so we can speculatively + * check on_list without danger of it being re-added. + */ + if (!tg->cfs_rq[cpu]->on_list) + continue; + + rq = cpu_rq(cpu); + + raw_spin_lock_irqsave(&rq->lock, flags); + list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); + raw_spin_unlock_irqrestore(&rq->lock, flags); + } } void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, @@ -8382,7 +8387,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) return 1; } -void unregister_fair_sched_group(struct task_group *tg, int cpu) { } +void unregister_fair_sched_group(struct task_group *tg) { } #endif /* CONFIG_FAIR_GROUP_SCHED */ -- cgit v1.1