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Date: Tue, 17 Dec 2013 11:48:20 +0400
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Subject: Re: [PATCH 1/2] memcg: fix memcg_size() calculation
From: Glauber Costa <glommer@gmail.com>
To: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@parallels.com>,
        LKML <linux-kernel@vger.kernel.org>, cgroups@vger.kernel.org,
        linux-mm@kvack.org, devel@openvz.org,
        Glauber Costa <glommer@openvz.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Balbir Singh <bsingharora@gmail.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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On Mon, Dec 16, 2013 at 8:47 PM, Michal Hocko <mhocko@suse.cz> wrote:
> On Sat 14-12-13 12:15:33, Vladimir Davydov wrote:
>> The mem_cgroup structure contains nr_node_ids pointers to
>> mem_cgroup_per_node objects, not the objects themselves.
>
> Ouch! This is 2k per node which is wasted. What a shame I haven't
> noticed this back then when reviewing 45cf7ebd5a033 (memcg: reduce the
> size of struct memcg 244-fold)
>
IIRC, they weren't pointers back then. I think they were embedded in
the structure, and I let
them embedded.
My mind may be tricking me, but I think I recall that Johannes changed
them to pointers
in a later time. No ?

In any case, this is correct.