diff options
| author | Chengming Zhou <zhouchengming@bytedance.com> | 2022-08-18 20:48:02 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-08-23 11:01:19 +0200 |
| commit | 7e2edaf61814fb6aa363989d718950c023b882d4 (patch) | |
| tree | 8634a813145e3b5f179ea5d67967a38f8c8e5740 /kernel/sched/fair.c | |
| parent | e1f078f50478a51849453341e7356cb298df00cf (diff) | |
sched/fair: Fix another detach on unattached task corner case
commit 7dc603c9028e ("sched/fair: Fix PELT integrity for new tasks")
fixed two load tracking problems for new task, including detach on
unattached new task problem.
There still left another detach on unattached task problem for the task
which has been woken up by try_to_wake_up() and waiting for actually
being woken up by sched_ttwu_pending().
try_to_wake_up(p)
cpu = select_task_rq(p)
if (task_cpu(p) != cpu)
set_task_cpu(p, cpu)
migrate_task_rq_fair()
remove_entity_load_avg() --> unattached
se->avg.last_update_time = 0;
__set_task_cpu()
ttwu_queue(p, cpu)
ttwu_queue_wakelist()
__ttwu_queue_wakelist()
task_change_group_fair()
detach_task_cfs_rq()
detach_entity_cfs_rq()
detach_entity_load_avg() --> detach on unattached task
set_task_rq()
attach_task_cfs_rq()
attach_entity_cfs_rq()
attach_entity_load_avg()
The reason of this problem is similar, we should check in detach_entity_cfs_rq()
that se->avg.last_update_time != 0, before do detach_entity_load_avg().
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20220818124805.601-7-zhouchengming@bytedance.com
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f52e7dc7f22d..e92bc053aff6 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11557,6 +11557,17 @@ static void detach_entity_cfs_rq(struct sched_entity *se) { struct cfs_rq *cfs_rq = cfs_rq_of(se); +#ifdef CONFIG_SMP + /* + * In case the task sched_avg hasn't been attached: + * - A forked task which hasn't been woken up by wake_up_new_task(). + * - A task which has been woken up by try_to_wake_up() but is + * waiting for actually being woken up by sched_ttwu_pending(). + */ + if (!se->avg.last_update_time) + return; +#endif + /* Catch up with the cfs_rq and remove our load when we leave */ update_load_avg(cfs_rq, se, 0); detach_entity_load_avg(cfs_rq, se); |