6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
[ Upstream commit c2e164ac33f75e0acb93004960c73bd9166d3d35 ]
There is no need to use runnable_avg when estimating util_est and that
even generates wrong behavior because one includes blocked tasks whereas
the other one doesn't. This can lead to accounting twice the waking task p,
once with the blocked runnable_avg and another one when adding its
util_est.
cpu's runnable_avg is already used when computing util_avg which is then
compared with util_est.
In some situation, feec will not select prev_cpu but another one on the
same performance domain because of higher max_util
Fixes: 7d0583cf9ec7 ("sched/fair, cpufreq: Introduce 'runnable boosting'")
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Tested-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Link: https://lore.kernel.org/r/20230706135144.324311-1-vincent.guittot@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/sched/fair.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b3e25be58e2b7..1d9c2482c5a35 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7289,9 +7289,6 @@ cpu_util(int cpu, struct task_struct *p, int dst_cpu, int boost)
util_est = READ_ONCE(cfs_rq->avg.util_est.enqueued);
- if (boost)
- util_est = max(util_est, runnable);
-
/*
* During wake-up @p isn't enqueued yet and doesn't contribute
* to any cpu_rq(cpu)->cfs.avg.util_est.enqueued.
--
2.40.1
