linux-kernel - Re: [patch for-3.7] mm, mempolicy: fix printing stack contents in numa

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Date:	Wed, 17 Oct 2012 12:38:55 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Dave Jones <davej@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	KOSAKI Motohiro <kosaki.motohiro@...il.com>,
	bhutchings@...arflare.com,
	Konstantin Khlebnikov <khlebnikov@...nvz.org>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Hugh Dickins <hughd@...gle.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [patch for-3.7] mm, mempolicy: fix printing stack contents in
 numa_maps

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@...crush: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@...crush: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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