From: Peter Zijlstra <peterz@infradead.org>
To: Kirill Tkhai <ktkhai@parallels.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
tkhai@yandex.ru
Subject: Re: [PATCH 1/2] sched: Rework migrate_tasks()
Date: Wed, 11 Jun 2014 12:57:33 +0200 [thread overview]
Message-ID: <20140611105733.GM6758@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1402480330.32126.14.camel@tkhai>
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On Wed, Jun 11, 2014 at 01:52:10PM +0400, Kirill Tkhai wrote:
>
> Currently migrate_tasks() skips throttled tasks,
> because they are not pickable by pick_next_task().
>
> These tasks stay on dead cpu even after they
> becomes unthrottled. They are not schedulable
> till user manually changes their affinity or till
> cpu becomes alive again.
>
> But for user this looks completely untransparent:
> task hangs, but it's not obvious what he has to do,
> because kernel does not report any problem.
>
> This situation may easily be triggered intentionally.
> Playing with extremely small cpu.cfs_quota_us causes
> it almost in 100% cases. In usual life it's very rare,
> but still possible for some unhappy user.
>
How about fixing the unthrottle code to validate the affinity?
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next prev parent reply other threads:[~2014-06-11 10:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20140611093417.27807.2288.stgit@tkhai>
2014-06-11 9:52 ` Kirill Tkhai
2014-06-11 10:57 ` Peter Zijlstra [this message]
2014-06-11 11:15 ` Kirill Tkhai
2014-06-11 11:24 ` Srikar Dronamraju
2014-06-11 12:20 ` Kirill Tkhai
2014-06-11 13:15 ` Srikar Dronamraju
2014-06-11 13:43 ` Kirill Tkhai
2014-06-11 19:33 ` Kirill Tkhai
2014-06-12 2:05 ` Mike Galbraith
2014-06-17 12:56 ` Kirill Tkhai
2014-06-11 9:52 ` [PATCH 2/2] sched: Rework check_for_tasks() Kirill Tkhai
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