[tip: sched/core] sched/fair: Reset sched_avg last_update_time before set_task_rq()
From: tip-bot2 for Chengming Zhou
Date: Tue Aug 23 2022 - 07:42:21 EST
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 5d6da83c44af70ede7bfd0fd6d1ef8a3b3e0402c
Gitweb: https://git.kernel.org/tip/5d6da83c44af70ede7bfd0fd6d1ef8a3b3e0402c
Author: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
AuthorDate: Thu, 18 Aug 2022 20:47:59 +08:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 23 Aug 2022 11:01:18 +02:00
sched/fair: Reset sched_avg last_update_time before set_task_rq()
set_task_rq() -> set_task_rq_fair() will try to synchronize the blocked
task's sched_avg when migrate, which is not needed for already detached
task.
task_change_group_fair() will detached the task sched_avg from prev cfs_rq
first, so reset sched_avg last_update_time before set_task_rq() to avoid that.
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220818124805.601-4-zhouchengming@xxxxxxxxxxxxx
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2c0eb2a..e4c0929 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -11660,12 +11660,12 @@ void init_cfs_rq(struct cfs_rq *cfs_rq)
static void task_change_group_fair(struct task_struct *p)
{
detach_task_cfs_rq(p);
- set_task_rq(p, task_cpu(p));
#ifdef CONFIG_SMP
/* Tell se's cfs_rq has been changed -- migrated */
p->se.avg.last_update_time = 0;
#endif
+ set_task_rq(p, task_cpu(p));
attach_task_cfs_rq(p);
}