From: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
To: Ying Han <yinghan-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: KAMEZAWA Hiroyuki
<kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
"linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org"
<linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>,
"hugh.dickins-IWqWACnzNjwqdlJmJB21zg@public.gmane.org"
<hugh.dickins-IWqWACnzNjwqdlJmJB21zg@public.gmane.org>,
"hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org"
<hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
"bsingharora-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org"
<bsingharora-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC] [PATCH 3/7 v2] memcg: remove PCG_MOVE_LOCK flag from pc->flags
Date: Thu, 26 Jan 2012 10:16:03 +0100 [thread overview]
Message-ID: <20120126091602.GC13421@tiehlicka.suse.cz> (raw)
In-Reply-To: <CALWz4iy0ajriTk7V0xL1+W7rDFS+-M5w4OdPjasMGUTH=ZLgrw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Wed 25-01-12 15:07:47, Ying Han wrote:
> On Tue, Jan 24, 2012 at 12:43 AM, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org> wrote:
> > On Mon 23-01-12 14:05:33, Ying Han wrote:
[...]
> >> Just want to make sure I understand it, even we make the lock
> >> per-memcg, there is still a false sharing of pc within one memcg.
> >
> > Yes that is true. I have missed that we might fault in several pages at
> > once but this would happen only during task move, right? And that is not
> > a hot path anyway. Or?
>
> I was thinking of page-statistics update which is hot path. If the
> moving task and non-moving task share the same per-memcg lock, any
> page-statistic update from the non-moving task will be blocked? Sorry
> If i missed something here :)
OK, I got your point, finally. I guess there is a plan to reduce the
effect by array of locks.
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@suse.cz>
To: Ying Han <yinghan@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"hugh.dickins@tiscali.co.uk" <hugh.dickins@tiscali.co.uk>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
cgroups@vger.kernel.org,
"bsingharora@gmail.com" <bsingharora@gmail.com>
Subject: Re: [RFC] [PATCH 3/7 v2] memcg: remove PCG_MOVE_LOCK flag from pc->flags
Date: Thu, 26 Jan 2012 10:16:03 +0100 [thread overview]
Message-ID: <20120126091602.GC13421@tiehlicka.suse.cz> (raw)
In-Reply-To: <CALWz4iy0ajriTk7V0xL1+W7rDFS+-M5w4OdPjasMGUTH=ZLgrw@mail.gmail.com>
On Wed 25-01-12 15:07:47, Ying Han wrote:
> On Tue, Jan 24, 2012 at 12:43 AM, Michal Hocko <mhocko@suse.cz> wrote:
> > On Mon 23-01-12 14:05:33, Ying Han wrote:
[...]
> >> Just want to make sure I understand it, even we make the lock
> >> per-memcg, there is still a false sharing of pc within one memcg.
> >
> > Yes that is true. I have missed that we might fault in several pages at
> > once but this would happen only during task move, right? And that is not
> > a hot path anyway. Or?
>
> I was thinking of page-statistics update which is hot path. If the
> moving task and non-moving task share the same per-memcg lock, any
> page-statistic update from the non-moving task will be blocked? Sorry
> If i missed something here :)
OK, I got your point, finally. I guess there is a plan to reduce the
effect by array of locks.
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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next prev parent reply other threads:[~2012-01-26 9:16 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-13 8:30 [RFC] [PATCH 0/7 v2] memcg: page_cgroup diet KAMEZAWA Hiroyuki
2012-01-13 8:32 ` [RFC] [PATCH 1/7 v2] memcg: remove unnecessary check in mem_cgroup_update_page_stat() KAMEZAWA Hiroyuki
2012-01-13 8:32 ` KAMEZAWA Hiroyuki
[not found] ` <20120113173227.df2baae3.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-17 15:16 ` Michal Hocko
2012-01-17 15:16 ` Michal Hocko
[not found] ` <20120117151619.GA21348-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-17 23:55 ` KAMEZAWA Hiroyuki
2012-01-17 23:55 ` KAMEZAWA Hiroyuki
[not found] ` <20120118085558.6ed1a988.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-18 13:01 ` Michal Hocko
2012-01-18 13:01 ` Michal Hocko
[not found] ` <20120118130102.GC31112-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-19 2:18 ` KAMEZAWA Hiroyuki
2012-01-19 2:18 ` KAMEZAWA Hiroyuki
2012-01-19 20:07 ` Ying Han
2012-01-19 20:07 ` Ying Han
2012-01-20 0:48 ` KAMEZAWA Hiroyuki
2012-01-20 0:48 ` KAMEZAWA Hiroyuki
[not found] ` <20120113173001.ee5260ca.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-13 8:33 ` [RFC] [PATCH 2/7 v2] memcg: add memory barrier for checking account move KAMEZAWA Hiroyuki
2012-01-13 8:33 ` KAMEZAWA Hiroyuki
[not found] ` <20120113173347.6231f510.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-17 15:26 ` Michal Hocko
2012-01-17 15:26 ` Michal Hocko
[not found] ` <20120117152635.GA22142-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-18 0:06 ` KAMEZAWA Hiroyuki
2012-01-18 0:06 ` KAMEZAWA Hiroyuki
2012-01-18 12:37 ` Michal Hocko
[not found] ` <20120118123759.GB31112-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-19 2:17 ` KAMEZAWA Hiroyuki
2012-01-19 2:17 ` KAMEZAWA Hiroyuki
2012-01-19 9:28 ` Michal Hocko
[not found] ` <20120119092833.GA13932-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-19 23:57 ` KAMEZAWA Hiroyuki
2012-01-19 23:57 ` KAMEZAWA Hiroyuki
[not found] ` <20120119111727.6337bde4.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-20 18:08 ` Ying Han
2012-01-20 18:08 ` Ying Han
[not found] ` <CALWz4iz59=-J+cif+XickXBG3zUSy58yHhkX6j3zbJyBXGzpYw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-01-23 9:04 ` Michal Hocko
2012-01-23 9:04 ` Michal Hocko
[not found] ` <20120123090436.GA12375-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-24 3:21 ` KAMEZAWA Hiroyuki
2012-01-24 3:21 ` KAMEZAWA Hiroyuki
2012-01-24 8:49 ` Michal Hocko
2012-01-24 8:49 ` Michal Hocko
2012-01-24 19:04 ` Ying Han
2012-01-24 19:04 ` Ying Han
[not found] ` <CALWz4iyaWtes=aU79DAbEfBsNUTaHKLK5HZbNfShaxgC8UX_TQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-01-25 11:07 ` Michal Hocko
2012-01-25 11:07 ` Michal Hocko
2012-01-13 8:40 ` [RFC] [PATCH 3/7 v2] memcg: remove PCG_MOVE_LOCK flag from pc->flags KAMEZAWA Hiroyuki
2012-01-13 8:40 ` KAMEZAWA Hiroyuki
2012-01-16 12:55 ` Kirill A. Shutemov
[not found] ` <20120116125526.GB25981-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>
2012-01-17 0:22 ` KAMEZAWA Hiroyuki
2012-01-17 0:22 ` KAMEZAWA Hiroyuki
[not found] ` <20120113174019.8dff3fc1.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-17 16:46 ` Michal Hocko
2012-01-17 16:46 ` Michal Hocko
2012-01-18 0:12 ` KAMEZAWA Hiroyuki
2012-01-18 10:47 ` Michal Hocko
[not found] ` <20120118104703.GA31112-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-18 23:53 ` KAMEZAWA Hiroyuki
2012-01-18 23:53 ` KAMEZAWA Hiroyuki
[not found] ` <20120119085309.616cadb4.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-23 22:05 ` Ying Han
2012-01-23 22:05 ` Ying Han
2012-01-24 4:59 ` KAMEZAWA Hiroyuki
2012-01-24 4:59 ` KAMEZAWA Hiroyuki
[not found] ` <CALWz4ixAT411PZMwngh17V8VZEDGbMNNzbWFwbpC5M-JO+TVOQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-01-24 8:43 ` Michal Hocko
2012-01-24 8:43 ` Michal Hocko
[not found] ` <20120124084335.GE26289-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-25 23:07 ` Ying Han
2012-01-25 23:07 ` Ying Han
[not found] ` <CALWz4iy0ajriTk7V0xL1+W7rDFS+-M5w4OdPjasMGUTH=ZLgrw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-01-26 9:16 ` Michal Hocko [this message]
2012-01-26 9:16 ` Michal Hocko
2012-01-23 22:02 ` Ying Han
[not found] ` <CALWz4izasaECifCYoRXL45x1YXYzACC=kUHQivnGZKRH+ySjuw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-01-24 4:47 ` KAMEZAWA Hiroyuki
2012-01-24 4:47 ` KAMEZAWA Hiroyuki
2012-01-25 22:48 ` Ying Han
2012-01-13 8:42 ` [RFC] [PATCH 5/7 v2] memcg: remove PCG_FILE_MAPPED KAMEZAWA Hiroyuki
2012-01-13 8:42 ` KAMEZAWA Hiroyuki
[not found] ` <20120113174223.aaf5a80c.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-19 14:07 ` Michal Hocko
2012-01-19 14:07 ` Michal Hocko
[not found] ` <20120119140737.GD13932-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-26 19:10 ` Ying Han
2012-01-26 19:10 ` Ying Han
2012-01-13 8:43 ` [RFC] [PATCH 6/7 v2] memcg: remove PCG_CACHE KAMEZAWA Hiroyuki
2012-01-13 8:43 ` KAMEZAWA Hiroyuki
2012-01-13 8:41 ` [RFC] [PATCH 4/7 v2] memcg: new scheme to update per-memcg page stat accounting KAMEZAWA Hiroyuki
2012-01-13 8:41 ` KAMEZAWA Hiroyuki
2012-01-18 16:45 ` Michal Hocko
2012-01-18 23:58 ` KAMEZAWA Hiroyuki
[not found] ` <20120113174138.ec7b64d9.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-26 19:01 ` Ying Han
2012-01-26 19:01 ` Ying Han
2012-01-13 8:45 ` [RFC] [PATCH 7/7 v2] memcg: make mem_cgroup_begin_update_stat to use global pcpu KAMEZAWA Hiroyuki
2012-01-13 8:45 ` KAMEZAWA Hiroyuki
2012-01-19 14:47 ` Michal Hocko
[not found] ` <20120119144712.GG13932-VqjxzfR4DlwKmadIfiO5sKVXKuFTiq87@public.gmane.org>
2012-01-20 2:19 ` KAMEZAWA Hiroyuki
2012-01-20 2:19 ` KAMEZAWA Hiroyuki
[not found] ` <20120120111947.400b2b15.kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
2012-01-20 8:38 ` Michal Hocko
2012-01-20 8:38 ` Michal Hocko
2012-01-20 8:40 ` Greg Thelen
[not found] ` <CAHH2K0ZzE55Dx=pz+cR1US3UnUbUxuyVjM=N3kf3NN+Rz8GJjQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-01-24 3:18 ` KAMEZAWA Hiroyuki
2012-01-24 3:18 ` KAMEZAWA Hiroyuki
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