Commit-ID: 502ce005ab95d5d9481768649dbab808845b24d7
Gitweb: http://git.kernel.org/tip/502ce005ab95d5d9481768649dbab808845b24d7
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 4 May 2017 15:31:22 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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 <tj@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170504133122.a6qjlj3hlblbjxux@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 */
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