From: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
To: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Subject: Re: [PATCH 3/4] memcg: split part of memcg creation to css_online
Date: Tue, 4 Dec 2012 09:52:28 +0100 [thread overview]
Message-ID: <20121204085228.GD31319@dhcp22.suse.cz> (raw)
In-Reply-To: <50BDB511.5070107-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
On Tue 04-12-12 12:32:17, Glauber Costa wrote:
> On 12/04/2012 12:17 PM, Michal Hocko wrote:
> >> But it should be extremely easy to protect against this. It is just a
> >> > matter of not returning online css in the iterator: then we'll never see
> >> > them until they are online. This also sounds a lot more correct than
> >> > returning allocated css.
> > Yes but... Look at your other patch which relies on iterator when counting
> > children to find out if there is any available.
> >
> And what is the problem with it ?
Bahh. Right you are because the value is copied only at the css_online
time. So even if mem_cgroup_hierarchy_write wouldn't see any child
(because they are still offline) and managed to set use_hierarchy=1 with
some children linked in all would be fixed in mem_cgroup_css_online.
P.S.
Hey mhocko stop saying crap.
--
Michal Hocko
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@suse.cz>
To: Glauber Costa <glommer@parallels.com>
Cc: cgroups@vger.kernel.org, linux-mm@kvack.org,
Tejun Heo <tj@kernel.org>,
kamezawa.hiroyu@jp.fujitsu.com,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 3/4] memcg: split part of memcg creation to css_online
Date: Tue, 4 Dec 2012 09:52:28 +0100 [thread overview]
Message-ID: <20121204085228.GD31319@dhcp22.suse.cz> (raw)
In-Reply-To: <50BDB511.5070107@parallels.com>
On Tue 04-12-12 12:32:17, Glauber Costa wrote:
> On 12/04/2012 12:17 PM, Michal Hocko wrote:
> >> But it should be extremely easy to protect against this. It is just a
> >> > matter of not returning online css in the iterator: then we'll never see
> >> > them until they are online. This also sounds a lot more correct than
> >> > returning allocated css.
> > Yes but... Look at your other patch which relies on iterator when counting
> > children to find out if there is any available.
> >
> And what is the problem with it ?
Bahh. Right you are because the value is copied only at the css_online
time. So even if mem_cgroup_hierarchy_write wouldn't see any child
(because they are still offline) and managed to set use_hierarchy=1 with
some children linked in all would be fixed in mem_cgroup_css_online.
P.S.
Hey mhocko stop saying crap.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2012-12-04 8:52 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-30 13:31 [PATCH 0/4] replace cgroup_lock with local lock in memcg Glauber Costa
2012-11-30 13:31 ` [PATCH 1/4] cgroup: warn about broken hierarchies only after css_online Glauber Costa
[not found] ` <1354282286-32278-2-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-11-30 15:11 ` Tejun Heo
2012-11-30 15:11 ` Tejun Heo
[not found] ` <20121130151158.GB3873-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-11-30 15:13 ` Glauber Costa
2012-11-30 15:13 ` Glauber Costa
[not found] ` <50B8CD32.4080807-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-11-30 15:45 ` Tejun Heo
2012-11-30 15:45 ` Tejun Heo
[not found] ` <20121130154504.GD3873-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-11-30 15:49 ` Michal Hocko
2012-11-30 15:49 ` Michal Hocko
2012-11-30 15:57 ` Glauber Costa
2012-11-30 13:31 ` [PATCH 2/4] memcg: prevent changes to move_charge_at_immigrate during task attach Glauber Costa
2012-11-30 15:19 ` Tejun Heo
2012-11-30 15:29 ` Glauber Costa
[not found] ` <1354282286-32278-3-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-04 9:29 ` Michal Hocko
2012-12-04 9:29 ` Michal Hocko
2012-11-30 13:31 ` [PATCH 3/4] memcg: split part of memcg creation to css_online Glauber Costa
[not found] ` <1354282286-32278-4-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-03 17:32 ` Michal Hocko
2012-12-03 17:32 ` Michal Hocko
[not found] ` <20121203173205.GI17093-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-04 8:05 ` Glauber Costa
2012-12-04 8:05 ` Glauber Costa
[not found] ` <50BDAEC1.8040805-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-04 8:17 ` Michal Hocko
2012-12-04 8:17 ` Michal Hocko
[not found] ` <20121204081756.GA31319-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-04 8:32 ` Glauber Costa
2012-12-04 8:32 ` Glauber Costa
[not found] ` <50BDB511.5070107-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-04 8:52 ` Michal Hocko [this message]
2012-12-04 8:52 ` Michal Hocko
2012-11-30 13:31 ` [PATCH 4/4] memcg: replace cgroup_lock with memcg specific memcg_lock Glauber Costa
[not found] ` <1354282286-32278-5-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-03 17:15 ` Michal Hocko
2012-12-03 17:15 ` Michal Hocko
[not found] ` <20121203171532.GG17093-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-03 17:30 ` Michal Hocko
2012-12-03 17:30 ` Michal Hocko
[not found] ` <20121203173002.GH17093-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-04 7:49 ` Glauber Costa
2012-12-04 7:49 ` Glauber Costa
2012-12-04 7:58 ` Glauber Costa
[not found] ` <50BDAD38.6030200-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-04 8:23 ` Michal Hocko
2012-12-04 8:23 ` Michal Hocko
[not found] ` <20121204082316.GB31319-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-04 8:31 ` Glauber Costa
2012-12-04 8:31 ` Glauber Costa
[not found] ` <50BDB4E3.4040107-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-12-04 8:45 ` Michal Hocko
2012-12-04 8:45 ` Michal Hocko
[not found] ` <20121204084544.GC31319-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-04 14:52 ` Tejun Heo
2012-12-04 14:52 ` Tejun Heo
[not found] ` <20121204145221.GA3885-9pTldWuhBndy/B6EtB590w@public.gmane.org>
2012-12-04 15:14 ` Michal Hocko
2012-12-04 15:14 ` Michal Hocko
[not found] ` <20121204151420.GL31319-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-04 15:22 ` Tejun Heo
2012-12-04 15:22 ` Tejun Heo
[not found] ` <20121204152225.GC3885-9pTldWuhBndy/B6EtB590w@public.gmane.org>
2012-12-05 14:35 ` Michal Hocko
2012-12-05 14:35 ` Michal Hocko
[not found] ` <20121205143537.GC9714-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-12-05 14:41 ` Tejun Heo
2012-12-05 14:41 ` Tejun Heo
[not found] ` <1354282286-32278-1-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-11-30 15:52 ` [PATCH 0/4] replace cgroup_lock with local lock in memcg Tejun Heo
2012-11-30 15:52 ` Tejun Heo
2012-11-30 15:59 ` Glauber Costa
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