diff options
| author | Vincent Guittot <vincent.guittot@linaro.org> | 2025-10-08 15:12:14 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-10-14 13:43:08 +0200 |
| commit | 17e3e88ed0b6318fde0d1c14df1a804711cab1b5 (patch) | |
| tree | 07804c19dc375fc350d1dc849f29d838a439dcce | |
| parent | ee6e44dfe6e50b4a5df853d933a96bdff5309e6e (diff) | |
sched/fair: Fix pelt lost idle time detection
The check for some lost idle pelt time should be always done when
pick_next_task_fair() fails to pick a task and not only when we call it
from the fair fast-path.
The case happens when the last running task on rq is a RT or DL task. When
the latter goes to sleep and the /Sum of util_sum of the rq is at the max
value, we don't account the lost of idle time whereas we should.
Fixes: 67692435c411 ("sched: Rework pick_next_task() slow-path")
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
| -rw-r--r-- | kernel/sched/fair.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index bc0b7ce8a65d..cee1793e8277 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8920,21 +8920,21 @@ simple: return p; idle: - if (!rf) - return NULL; - - new_tasks = sched_balance_newidle(rq, rf); + if (rf) { + new_tasks = sched_balance_newidle(rq, rf); - /* - * Because sched_balance_newidle() releases (and re-acquires) rq->lock, it is - * possible for any higher priority task to appear. In that case we - * must re-start the pick_next_entity() loop. - */ - if (new_tasks < 0) - return RETRY_TASK; + /* + * Because sched_balance_newidle() releases (and re-acquires) + * rq->lock, it is possible for any higher priority task to + * appear. In that case we must re-start the pick_next_entity() + * loop. + */ + if (new_tasks < 0) + return RETRY_TASK; - if (new_tasks > 0) - goto again; + if (new_tasks > 0) + goto again; + } /* * rq is about to be idle, check if we need to update the |