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authorQuentin Perret <qperret@google.com>2020-11-12 11:12:01 +0000
committerPeter Zijlstra <peterz@infradead.org>2020-11-17 13:15:27 +0100
commit8e1ac4299a6e8726de42310d9c1379f188140c71 (patch)
tree8eb8454794c58a9978cc4f09886fbe5af764fd7f
parent8d4d9c7b4333abccb3bf310d76ef7ea2edb9828f (diff)
downloadlinux-8e1ac4299a6e8726de42310d9c1379f188140c71.tar.bz2
sched/fair: Fix overutilized update in enqueue_task_fair()
enqueue_task_fair() attempts to skip the overutilized update for new tasks as their util_avg is not accurate yet. However, the flag we check to do so is overwritten earlier on in the function, which makes the condition pretty much a nop. Fix this by saving the flag early on. Fixes: 2802bf3cd936 ("sched/fair: Add over-utilization/tipping point indicator") Reported-by: Rick Yiu <rickyiu@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lkml.kernel.org/r/20201112111201.2081902-1-qperret@google.com
-rw-r--r--kernel/sched/fair.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8e563cf2b5e7..56a8ca93a971 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5477,6 +5477,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
int idle_h_nr_running = task_has_idle_policy(p);
+ int task_new = !(flags & ENQUEUE_WAKEUP);
/*
* The code below (indirectly) updates schedutil which looks at
@@ -5549,7 +5550,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
* into account, but that is not straightforward to implement,
* and the following generally works well enough in practice.
*/
- if (flags & ENQUEUE_WAKEUP)
+ if (!task_new)
update_overutilized_status(rq);
enqueue_throttle: