diff options
| author | Vincent Guittot <vincent.guittot@linaro.org> | 2026-01-21 17:33:17 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-01-21 17:46:08 +0100 |
| commit | 98c88dc8a1ace642d9021b103b28cba7b51e3abc (patch) | |
| tree | 286b90ed285ceec45a579c39b767898bdb03f15e /kernel | |
| parent | 24d479d26b25bce5faea3ddd9fa8f3a6c3129ea7 (diff) | |
sched/fair: Fix pelt clock sync when entering idle
Samuel and Alex reported regressions of the util_avg of RT rq with
commit 17e3e88ed0b6 ("sched/fair: Fix pelt lost idle time detection").
It happens that fair is updating and syncing the pelt clock with task one
when pick_next_task_fair() fails to pick a task but before the prev
scheduling class got a chance to update its pelt signals.
Move update_idle_rq_clock_pelt() in set_next_task_idle() which is called
after prev class has been called.
Fixes: 17e3e88ed0b6 ("sched/fair: Fix pelt lost idle time detection")
Closes: https://lore.kernel.org/all/CAG2KctpO6VKS6GN4QWDji0t92_gNBJ7HjjXrE+6H+RwRXt=iLg@mail.gmail.com/
Closes: https://lore.kernel.org/all/8cf19bf0e0054dcfed70e9935029201694f1bb5a.camel@mediatek.com/
Reported-by: Samuel Wu <wusamuel@google.com>
Reported-by: Alex Hoh <Alex.Hoh@mediatek.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Samuel Wu <wusamuel@google.com>
Tested-by: Alex Hoh <Alex.Hoh@mediatek.com>
Link: https://patch.msgid.link/20260121163317.505635-1-vincent.guittot@linaro.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 6 | ||||
| -rw-r--r-- | kernel/sched/idle.c | 6 |
2 files changed, 6 insertions, 6 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e71302282671..a148c61a8085 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8995,12 +8995,6 @@ idle: goto again; } - /* - * rq is about to be idle, check if we need to update the - * lost_idle_time of clock_pelt - */ - update_idle_rq_clock_pelt(rq); - return NULL; } diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index c174afe1dd17..abf8f15d60c9 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -468,6 +468,12 @@ static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool fir scx_update_idle(rq, true, true); schedstat_inc(rq->sched_goidle); next->se.exec_start = rq_clock_task(rq); + + /* + * rq is about to be idle, check if we need to update the + * lost_idle_time of clock_pelt + */ + update_idle_rq_clock_pelt(rq); } struct task_struct *pick_task_idle(struct rq *rq, struct rq_flags *rf) |