shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-09 04:10:18 +09:00
Code Issues Packages Projects Releases Wiki Activity

sched/fair: Fix pelt lost idle time detection

Browse Source 
[ Upstream commit 17e3e88ed0b6318fde0d1c14df1a804711cab1b5 ]

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: 67692435c4 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Vincent Guittot
2025-10-08 15:12:14 +02:00
committed by Greg Kroah-Hartman
parent 3359a93f45
commit 66c29d9fc1
1 changed files with 13 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
kernel/sched/fair.c
View File

@@ -8528,21 +8528,21 @@ done: __maybe_unused;
return p;
idle:
if (!rf)
return NULL;
if (rf) {
new_tasks = sched_balance_newidle(rq, 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