From: Prarit Bhargava <prarit@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
mingo@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -v2 -tip] fix race between stop_two_cpus and stop_cpus
Date: Fri, 01 Nov 2013 10:49:06 -0400 [thread overview]
Message-ID: <5273BF62.6050903@redhat.com> (raw)
In-Reply-To: <20131101144728.GY2400@suse.de>
On 11/01/2013 10:47 AM, Mel Gorman wrote:
> 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>
I'll test for a few hours and get back to everyone by the end of the day.
P.
>
next prev parent reply other threads:[~2013-11-01 14:49 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
2013-11-01 14:49 ` Prarit Bhargava [this message]
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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