From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Sha Zhengju <handai.szj@gmail.com>
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, mhocko@suse.cz, akpm@linux-foundation.org,
gthelen@google.com, fengguang.wu@intel.com,
glommer@parallels.com, Sha Zhengju <handai.szj@taobao.com>
Subject: Re: [PATCH V3 6/8] memcg: Don't account root_mem_cgroup page statistics
Date: Fri, 28 Dec 2012 10:04:11 +0900 [thread overview]
Message-ID: <50DCF00B.5040100@jp.fujitsu.com> (raw)
In-Reply-To: <1356456447-14740-1-git-send-email-handai.szj@taobao.com>
(2012/12/26 2:27), Sha Zhengju wrote:
> From: Sha Zhengju <handai.szj@taobao.com>
>
> If memcg is enabled and no non-root memcg exists, all allocated pages
> belongs to root_mem_cgroup and go through root memcg statistics routines
> which brings some overheads. So for the sake of performance, we can give
> up accounting stats of root memcg for MEM_CGROUP_STAT_FILE_MAPPED/FILE_DIRTY
> /WRITEBACK and instead we pay special attention while showing root
> memcg numbers in memcg_stat_show(): as we don't account root memcg stats
> anymore, the root_mem_cgroup->stat numbers are actually 0. But because of
> hierachy, figures of root_mem_cgroup may just represent numbers of pages
> used by its own tasks(not belonging to any other child cgroup). So here we
> fake these root numbers by using stats of global state and all other memcg.
> That is for root memcg:
> nr(MEM_CGROUP_STAT_FILE_MAPPED) = global_page_state(NR_FILE_MAPPED) -
> sum_of_all_memcg(MEM_CGROUP_STAT_FILE_MAPPED);
> Dirty/Writeback pages accounting are in the similar way.
>
> Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
isn't it better to use mem_cgroup_is_root() call rather than
direct comparison (memcg == root_mem_cgroup) ?
Anyway, Ack to this approach.
Thanks,
-Kame
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next prev parent reply other threads:[~2012-12-28 1:04 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-25 17:18 [PATCH V3 0/8] Per-cgroup page stat accounting Sha Zhengju
2012-12-25 17:20 ` [PATCH V3 1/8] memcg: remove MEMCG_NR_FILE_MAPPED Sha Zhengju
2012-12-25 17:22 ` [PATCH V3 2/8] Make TestSetPageDirty and dirty page accounting in one func Sha Zhengju
2012-12-28 0:39 ` Kamezawa Hiroyuki
2013-01-05 2:34 ` Sha Zhengju
2013-01-02 9:08 ` Michal Hocko
2013-01-05 2:49 ` Sha Zhengju
2013-01-05 10:45 ` Michal Hocko
2012-12-25 17:24 ` [PATCH V3 3/8] use vfs __set_page_dirty interface instead of doing it inside filesystem Sha Zhengju
2012-12-28 0:41 ` Kamezawa Hiroyuki
2012-12-25 17:26 ` [PATCH V3 4/8] memcg: add per cgroup dirty pages accounting Sha Zhengju
2013-01-02 10:44 ` Michal Hocko
2013-01-05 4:48 ` Sha Zhengju
2013-01-06 20:02 ` Hugh Dickins
2013-01-07 7:49 ` Kamezawa Hiroyuki
2013-01-09 5:15 ` Hugh Dickins
2013-01-09 7:24 ` Kamezawa Hiroyuki
2013-01-09 14:35 ` Sha Zhengju
2013-01-09 14:47 ` Michal Hocko
2013-01-07 7:25 ` Kamezawa Hiroyuki
2013-01-09 15:02 ` Sha Zhengju
2013-01-10 2:16 ` Kamezawa Hiroyuki
2013-01-10 4:26 ` Sha Zhengju
2013-01-10 5:03 ` Kamezawa Hiroyuki
2013-01-10 8:28 ` Sha Zhengju
2013-05-03 9:11 ` Michal Hocko
2013-05-03 9:59 ` Sha Zhengju
2013-01-06 20:07 ` Greg Thelen
2013-01-09 9:45 ` Sha Zhengju
2012-12-25 17:26 ` [PATCH V3 5/8] memcg: add per cgroup writeback " Sha Zhengju
2012-12-28 0:52 ` Kamezawa Hiroyuki
2013-01-02 11:15 ` Michal Hocko
2013-01-06 20:07 ` Greg Thelen
2013-01-09 9:08 ` Sha Zhengju
2012-12-25 17:27 ` [PATCH V3 6/8] memcg: Don't account root_mem_cgroup page statistics Sha Zhengju
2012-12-28 1:04 ` Kamezawa Hiroyuki [this message]
2013-01-05 7:38 ` Sha Zhengju
2013-01-02 12:27 ` Michal Hocko
2013-01-05 10:52 ` Sha Zhengju
2013-01-09 12:57 ` Michal Hocko
2012-12-25 17:27 ` [PATCH V3 7/8] memcg: disable memcg page stat accounting code when not in use Sha Zhengju
2012-12-28 1:06 ` Kamezawa Hiroyuki
2012-12-28 1:45 ` Kamezawa Hiroyuki
2013-01-05 11:06 ` Sha Zhengju
2013-01-02 13:35 ` Michal Hocko
2012-12-25 17:28 ` [PATCH V3 8/8] memcg: Document cgroup dirty/writeback memory statistics Sha Zhengju
2012-12-28 1:10 ` Kamezawa Hiroyuki
2013-01-06 2:55 ` Sha Zhengju
2013-01-02 13:36 ` Michal Hocko
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