The following commit has been merged into the sched/core branch of tip:
Commit-ID: 96500560f0c73c71bca1b27536c6254fa0e8ce37
Gitweb: https://git.kernel.org/tip/96500560f0c73c71bca1b27536c6254fa0e8ce37
Author: Hao Jia <jiahao.os@xxxxxxxxxxxxx>
AuthorDate: Tue, 13 Jun 2023 16:20:10 +08:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 16 Jun 2023 22:08:12 +02:00
sched/core: Avoid double calling update_rq_clock() in __balance_push_cpu_stop()
There is a double update_rq_clock() invocation:
__balance_push_cpu_stop()
update_rq_clock()
__migrate_task()
update_rq_clock()
Sadly select_fallback_rq() also needs update_rq_clock() for
__do_set_cpus_allowed(), it is not possible to remove the update from
__balance_push_cpu_stop(). So remove it from __migrate_task() and
ensure all callers of this function call update_rq_clock() prior to
calling it.
Signed-off-by: Hao Jia <jiahao.os@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20230613082012.49615-3-jiahao.os@xxxxxxxxxxxxx
---
kernel/sched/core.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 442efe5..c7db597 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2546,7 +2546,6 @@ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
if (!is_cpu_allowed(p, dest_cpu))
return rq;
- update_rq_clock(rq);
rq = move_queued_task(rq, rf, p, dest_cpu);
return rq;
@@ -2604,10 +2603,12 @@ static int migration_cpu_stop(void *data)
goto out;
}
- if (task_on_rq_queued(p))
+ if (task_on_rq_queued(p)) {
+ update_rq_clock(rq);
rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
- else
+ } else {
p->wake_cpu = arg->dest_cpu;
+ }
/*
* XXX __migrate_task() can fail, at which point we might end
|