lkml.org 
[lkml]   [2010]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 2/4] memcg: catch negative per-cpu sums in dirty info
On Sun,  7 Nov 2010 23:14:37 +0100
Johannes Weiner <hannes@cmpxchg.org> wrote:

> Folding the per-cpu counters can yield a negative value in case of
> accounting races between CPUs.
>
> When collecting the dirty info, the code would read those sums into an
> unsigned variable and then check for it being negative, which can not
> work.
>
> Instead, fold the counters into a signed local variable, make the
> check, and only then assign it.
>
> This way, the function signals correctly when there are insane values
> instead of leaking them out to the caller.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>



\
 
 \ /
  Last update: 2010-11-16 04:47    [W:0.129 / U:1.880 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site