From: Ingo Molnar <mingo@kernel.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Xie XiuQi <xiexiuqi@huawei.com>, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
xiezhipeng1@huawei.com, huawei.libin@huawei.com,
linux-kernel <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Tejun Heo <tj@kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] sched: fix infinity loop in update_blocked_averages
Date: Sun, 30 Dec 2018 13:04:35 +0100 [thread overview]
Message-ID: <20181230120435.GA17231@gmail.com> (raw)
In-Reply-To: <CAKfTPtDRGULW3mdFzeyT=OBPdtPsz-6BG-=UGWbK6RQ7Lg8YpA@mail.gmail.com>
* Vincent Guittot <vincent.guittot@linaro.org> wrote:
> > Reported-by: Zhipeng Xie <xiezhipeng1@huawei.com>
> > Cc: Bin Li <huawei.libin@huawei.com>
> > Cc: <stable@vger.kernel.org> [4.10+]
> > Fixes: 9c2791f936ef (sched/fair: Fix hierarchical order in rq->leaf_cfs_rq_list)
>
> If it only happens in update_blocked_averages(), the del leaf has been added by:
> a9e7f6544b9c (sched/fair: Fix O(nr_cgroups) in load balance path)
So I think until we are confident in the proposed fixes, how about
applying Linus's patch that reverts a9e7f6544b9c and simplifies the list
manipulation?
That way we can re-introduce the O(nr_cgroups) optimization without
pressure.
I'll prepare a commit for sched/urgent that does this, please holler if
any of you disagrees!
Thanks,
Ingo
next prev parent reply other threads:[~2018-12-30 12:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-27 3:04 [PATCH] sched: fix infinity loop in update_blocked_averages Xie XiuQi
2018-12-27 9:21 ` Vincent Guittot
2018-12-27 10:21 ` Vincent Guittot
2018-12-27 10:23 ` Vincent Guittot
2018-12-27 16:39 ` Sargun Dhillon
2018-12-27 17:01 ` Vincent Guittot
2018-12-27 18:15 ` Linus Torvalds
2018-12-27 21:08 ` Sargun Dhillon
2018-12-27 21:46 ` Linus Torvalds
2018-12-28 1:15 ` Tejun Heo
2018-12-28 1:36 ` Linus Torvalds
2018-12-28 1:53 ` Tejun Heo
2018-12-28 2:02 ` Tejun Heo
2018-12-28 2:30 ` Xie XiuQi
2018-12-28 5:38 ` Sargun Dhillon
2018-12-28 9:30 ` Vincent Guittot
2018-12-28 14:26 ` Sargun Dhillon
2018-12-28 16:54 ` Tejun Heo
2018-12-28 17:25 ` Vincent Guittot
2018-12-28 17:46 ` Tejun Heo
2018-12-28 18:04 ` Vincent Guittot
2018-12-28 10:25 ` Xiezhipeng (EulerOS)
2018-12-30 12:04 ` Ingo Molnar [this message]
2018-12-30 12:31 ` [PATCH] sched: Fix infinite loop in update_blocked_averages() by reverting a9e7f6544b9c Ingo Molnar
2018-12-30 12:36 ` [PATCH] sched: fix infinity loop in update_blocked_averages Vincent Guittot
2018-12-30 12:54 ` Ingo Molnar
2018-12-30 13:00 ` [tip:sched/urgent] sched/fair: Fix infinite loop in update_blocked_averages() by reverting a9e7f6544b9c tip-bot for Linus Torvalds
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