Message-ID: <5028B4DA.6000507@parallels.com>
Date: Mon, 13 Aug 2012 12:03:38 +0400
From: Glauber Costa <glommer@parallels.com>
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To: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        <cgroups@vger.kernel.org>, <devel@openvz.org>,
        Michal Hocko <mhocko@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>, David Rientjes <rientjes@google.com>,
        Pekka Enberg <penberg@kernel.org>,
        Pekka Enberg <penberg@cs.helsinki.fi>,
        Suleiman Souhlal <suleiman@google.com>, Mel Gorman <mgorman@suse.de>
Subject: Re: [PATCH v2 07/11] mm: Allocate kernel pages to the right memcg
References: <1344517279-30646-1-git-send-email-glommer@parallels.com> <1344517279-30646-8-git-send-email-glommer@parallels.com> <502545D2.80708@jp.fujitsu.com>
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On 08/10/2012 09:33 PM, Kamezawa Hiroyuki wrote:
> (2012/08/09 22:01), Glauber Costa wrote:
>> When a process tries to allocate a page with the __GFP_KMEMCG flag, the
>> page allocator will call the corresponding memcg functions to validate
>> the allocation. Tasks in the root memcg can always proceed.
>>
>> To avoid adding markers to the page - and a kmem flag that would
>> necessarily follow, as much as doing page_cgroup lookups for no reason,
>> whoever is marking its allocations with __GFP_KMEMCG flag is responsible
>> for telling the page allocator that this is such an allocation at
>> free_pages() time. This is done by the invocation of
>> __free_accounted_pages() and free_accounted_pages().
>>
>> Signed-off-by: Glauber Costa <glommer@parallels.com>
>> CC: Christoph Lameter <cl@linux.com>
>> CC: Pekka Enberg <penberg@cs.helsinki.fi>
>> CC: Michal Hocko <mhocko@suse.cz>
>> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>> CC: Johannes Weiner <hannes@cmpxchg.org>
>> CC: Suleiman Souhlal <suleiman@google.com>
> 
> Ah, ok. free_accounted_page() seems good.
> 
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> I myself is okay with this. But...
> 
> Because you add a new hook to alloc_pages(), please get Ack from Mel
> before requesting merge.
> 
> Thanks,
> -Kame

Absolutely.

Mel, would you mind taking a look at this series and commenting on this?

Thanks in advance.

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