diff options
| author | Phil Auld <pauld@redhat.com> | 2020-05-12 09:52:22 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-27 17:46:52 +0200 |
| commit | b5100186021aff0d388aab48dfbfdb3c06955daf (patch) | |
| tree | f3c24e515b0b21d5b403760ac734eb9737062cb4 | |
| parent | 8b13f5657fa836a869cc245e529fd3b36207f59b (diff) | |
sched/fair: Fix enqueue_task_fair() warning some more
[ Upstream commit b34cb07dde7c2346dec73d053ce926aeaa087303 ]
sched/fair: Fix enqueue_task_fair warning some more
The recent patch, fe61468b2cb (sched/fair: Fix enqueue_task_fair warning)
did not fully resolve the issues with the rq->tmp_alone_branch !=
&rq->leaf_cfs_rq_list warning in enqueue_task_fair. There is a case where
the first for_each_sched_entity loop exits due to on_rq, having incompletely
updated the list. In this case the second for_each_sched_entity loop can
further modify se. The later code to fix up the list management fails to do
what is needed because se does not point to the sched_entity which broke out
of the first loop. The list is not fixed up because the throttled parent was
already added back to the list by a task enqueue in a parallel child hierarchy.
Address this by calling list_add_leaf_cfs_rq if there are throttled parents
while doing the second for_each_sched_entity loop.
Fixes: fe61468b2cb ("sched/fair: Fix enqueue_task_fair warning")
Suggested-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200512135222.GC2201@lorien.usersys.redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | kernel/sched/fair.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 42cc3de24dcc..193b6ab74d7f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5254,6 +5254,13 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) /* end evaluation on encountering a throttled cfs_rq */ if (cfs_rq_throttled(cfs_rq)) goto enqueue_throttle; + + /* + * One parent has been throttled and cfs_rq removed from the + * list. Add it back to not break the leaf list. + */ + if (throttled_hierarchy(cfs_rq)) + list_add_leaf_cfs_rq(cfs_rq); } enqueue_throttle: |