Commit-ID: 502ce005ab95d5d9481768649dbab808845b24d7 Gitweb: http://git.kernel.org/tip/502ce005ab95d5d9481768649dbab808845b24d7 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Thu, 4 May 2017 15:31:22 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Mon, 15 May 2017 10:15:35 +0200
sched/fair: Use task_groups instead of leaf_cfs_rq_list to walk all cfs_rqs In order to allow leaf_cfs_rq_list to remove entries switch the bandwidth hotplug code over to the task_groups list. Suggested-by: Tejun Heo <t...@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Chris Mason <c...@fb.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Mike Galbraith <efa...@gmx.de> Cc: Paul Turner <p...@google.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/20170504133122.a6qjlj3hlblbj...@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/sched/fair.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index eede181..c8fa777 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4642,24 +4642,43 @@ static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) hrtimer_cancel(&cfs_b->slack_timer); } +/* + * Both these cpu hotplug callbacks race against unregister_fair_sched_group() + * + * The race is harmless, since modifying bandwidth settings of unhooked group + * bits doesn't do much. + */ + +/* cpu online calback */ static void __maybe_unused update_runtime_enabled(struct rq *rq) { - struct cfs_rq *cfs_rq; + struct task_group *tg; - for_each_leaf_cfs_rq(rq, cfs_rq) { - struct cfs_bandwidth *cfs_b = &cfs_rq->tg->cfs_bandwidth; + lockdep_assert_held(&rq->lock); + + rcu_read_lock(); + list_for_each_entry_rcu(tg, &task_groups, list) { + struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; + struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; raw_spin_lock(&cfs_b->lock); cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF; raw_spin_unlock(&cfs_b->lock); } + rcu_read_unlock(); } +/* cpu offline callback */ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) { - struct cfs_rq *cfs_rq; + struct task_group *tg; + + lockdep_assert_held(&rq->lock); + + rcu_read_lock(); + list_for_each_entry_rcu(tg, &task_groups, list) { + struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; - for_each_leaf_cfs_rq(rq, cfs_rq) { if (!cfs_rq->runtime_enabled) continue; @@ -4677,6 +4696,7 @@ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) if (cfs_rq_throttled(cfs_rq)) unthrottle_cfs_rq(cfs_rq); } + rcu_read_unlock(); } #else /* CONFIG_CFS_BANDWIDTH */
