On Mon, May 11, 2020 at 04:44:10PM -0400, Phil Auld wrote: > Peter/Ingo, do you want me to resend or can you fix when applying?
I now have this, do I need more edits? --- Subject: sched/fair: Fix enqueue_task_fair warning some more From: Phil Auld <pa...@redhat.com> Date: Thu, 7 May 2020 16:36:12 -0400 From: Phil Auld <pa...@redhat.com> 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 no longer points to the sched_entity which broke out of the first loop. 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.guit...@linaro.org> Signed-off-by: Phil Auld <pa...@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Reviewed-by: Vincent Guittot <vincent.guit...@linaro.org> Reviewed-by: Dietmar Eggemann <dietmar.eggem...@arm.com> Link: https://lkml.kernel.org/r/20200507203612.gf19...@lorien.usersys.redhat.com --- kernel/sched/fair.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5479,6 +5479,13 @@ enqueue_task_fair(struct rq *rq, struct /* 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:
