Date: Wed, 17 Oct 2012 12:38:55 -0700 (PDT)
From: David Rientjes <rientjes@google.com>
To: Dave Jones <davej@redhat.com>, Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@gmail.com>, bhutchings@solarflare.com,
        Konstantin Khlebnikov <khlebnikov@openvz.org>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Hugh Dickins <hughd@google.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch for-3.7] mm, mempolicy: fix printing stack contents in
 numa_maps
In-Reply-To: <20121017193229.GC16805@redhat.com>
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On Wed, 17 Oct 2012, Dave Jones wrote:

>  > Sounds good.  Is it possible to verify that policy_cache isn't getting 
>  > larger than normal in /proc/slabinfo, i.e. when all processes with a 
>  > task mempolicy or shared vma policy have exited, are there still a 
>  > significant number of active objects?
> 
> Killing the fuzzer caused it to drop dramatically.
> 
> Before:
> (15:29:59:davej@bitcrush:trinity[master])$ sudo cat /proc/slabinfo  | grep policy
> shared_policy_node   2931   2967    376   43    4 : tunables    0    0    0 : slabdata     69     69      0
> numa_policy         2971   6545    464   35    4 : tunables    0    0    0 : slabdata    187    187      0
> 
> After:
> (15:30:16:davej@bitcrush:trinity[master])$ sudo cat /proc/slabinfo  | grep policy
> shared_policy_node      0    215    376   43    4 : tunables    0    0    0 : slabdata      5      5      0
> numa_policy           15    175    464   35    4 : tunables    0    0    0 : slabdata      5      5      0
> 

Excellent, thanks.  This shows that the refcounting is working properly 
and we're not leaking any references as a result of this change causing 
the mempolicies to never be freed.  ("numa_policy" turns out to be 
policy_cache in the code, so thanks for checking both of them.)

Could I add your tested-by?
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