Re: [PATCH -v2 -tip] fix race between stop_two_cpus and stop_cpus

[Mel Gorman]

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@xxxxxxxxxx>
> ---
> 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@xxxxxxx>

-- 
Mel Gorman
SUSE Labs
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