From: Mel Gorman <mgorman@suse.de>
To: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
mingo@kernel.org, prarit@redhat.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -v2 -tip] fix race between stop_two_cpus and stop_cpus
Date: Fri, 1 Nov 2013 14:47:28 +0000 [thread overview]
Message-ID: <20131101144728.GY2400@suse.de> (raw)
In-Reply-To: <20131101104146.03d1e043@annuminas.surriel.com>
On Fri, Nov 01, 2013 at 10:41:46AM -0400, Rik van Riel wrote:
> Subject: fix race between stop_two_cpus and stop_cpus
>
> There is a race between stop_two_cpus, and the global stop_cpus.
>
> It is possible for two CPUs to get their stopper functions queued
> "backwards" from one another, resulting in the stopper threads
> getting stuck, and the system hanging. This can happen because
> queuing up stoppers is not synchronized.
>
> This patch adds synchronization between stop_cpus (a rare operation),
> and stop_two_cpus.
>
> Signed-off-by: Rik van Riel <riel@redhat.com>
> ---
> v2: use lglock, as suggested by Peter & Mel, thanks to both of you
> for insisting on nicer code :)
>
This is a tad more comprehensible :). Thanks!
Acked-by: Mel Gorman <mgorman@suse.de>
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2013-11-01 14:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-31 20:31 [PATCH -tip] fix race between stop_two_cpus and stop_cpus Rik van Riel
2013-11-01 11:08 ` Mel Gorman
2013-11-01 11:36 ` Rik van Riel
2013-11-01 12:08 ` Prarit Bhargava
2013-11-01 13:44 ` Mel Gorman
2013-11-01 14:24 ` Peter Zijlstra
2013-11-01 14:27 ` Rik van Riel
2013-11-01 14:41 ` [PATCH -v2 " Rik van Riel
2013-11-01 14:47 ` Mel Gorman [this message]
2013-11-01 14:49 ` Prarit Bhargava
2013-11-01 18:24 ` Prarit Bhargava
2013-11-11 17:52 ` [tip:sched/core] stop_machine: Fix race between stop_two_cpus() and stop_cpus() tip-bot for Rik van Riel
2013-11-01 11:39 ` [PATCH -tip] fix race between stop_two_cpus and stop_cpus Prarit Bhargava
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