From: Michal Hocko <mhocko@suse.cz>
To: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Ying Han <yinghan@google.com>, Tejun Heo <htejun@gmail.com>,
Glauber Costa <glommer@parallels.com>,
Li Zefan <lizefan@huawei.com>
Subject: Re: [patch v2 3/6] memcg: rework mem_cgroup_iter to use cgroup iterators
Date: Wed, 28 Nov 2012 10:17:45 +0100 [thread overview]
Message-ID: <20121128091745.GC12309@dhcp22.suse.cz> (raw)
In-Reply-To: <50B5CFBF.2090100@jp.fujitsu.com>
On Wed 28-11-12 17:47:59, KAMEZAWA Hiroyuki wrote:
> (2012/11/27 3:47), Michal Hocko wrote:
[...]
> > + /*
> > + * Even if we found a group we have to make sure it is alive.
> > + * css && !memcg means that the groups should be skipped and
> > + * we should continue the tree walk.
> > + * last_visited css is safe to use because it is protected by
> > + * css_get and the tree walk is rcu safe.
> > + */
> > + if (css == &root->css || (css && css_tryget(css)))
> > + memcg = mem_cgroup_from_css(css);
>
> Could you note that this iterator will never visit dangling(removed)
> memcg, somewhere ?
OK, I can add it to the function comment but the behavior hasn't changed
so I wouldn't like to confuse anybody.
> Hmm, I'm not sure but it may be trouble at shrkinking dangling
> kmem_cache(slab).
We do not shrink slab at all. Those objects that are in a dead memcg
wait for their owner tho release them which will make the dangling group
eventually go away
>
> Costa, how do you think ?
>
> I guess there is no problem with swap and not against the way you go.
Yes, swap should be OK. Pages charged against removed memcg will
fallback to the the current's mm (try_get_mem_cgroup_from_page and
__mem_cgroup_try_charge_swapin)
[...]
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2012-11-28 9:17 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-26 18:47 rework mem_cgroup iterator Michal Hocko
2012-11-26 18:47 ` [patch v2 1/6] memcg: synchronize per-zone iterator access by a spinlock Michal Hocko
2012-11-26 18:47 ` [patch v2 2/6] memcg: keep prev's css alive for the whole mem_cgroup_iter Michal Hocko
2012-11-28 8:38 ` Kamezawa Hiroyuki
2012-11-26 18:47 ` [patch v2 3/6] memcg: rework mem_cgroup_iter to use cgroup iterators Michal Hocko
2012-11-28 8:47 ` Kamezawa Hiroyuki
2012-11-28 9:17 ` Michal Hocko [this message]
2012-11-28 9:23 ` Glauber Costa
2012-11-28 9:33 ` Michal Hocko
2012-11-28 9:35 ` Glauber Costa
2012-11-30 4:07 ` Kamezawa Hiroyuki
2012-12-07 3:39 ` Ying Han
2012-12-07 3:43 ` Ying Han
2012-12-07 8:58 ` Michal Hocko
2012-12-07 17:12 ` Ying Han
2012-12-07 17:27 ` Michal Hocko
2012-12-07 19:16 ` Ying Han
2012-12-07 19:35 ` Michal Hocko
2012-12-07 9:01 ` Michal Hocko
2012-12-09 16:59 ` Ying Han
2012-12-11 15:50 ` Michal Hocko
2012-12-11 16:15 ` Michal Hocko
2012-12-11 18:10 ` Michal Hocko
2012-12-11 22:43 ` Ying Han
2012-12-12 8:55 ` Michal Hocko
2012-12-12 17:57 ` Ying Han
2012-12-12 18:08 ` Michal Hocko
2012-12-11 22:31 ` Ying Han
2012-12-09 19:39 ` Ying Han
2012-12-11 15:54 ` Michal Hocko
2012-12-11 22:36 ` Ying Han
2012-12-12 9:06 ` Michal Hocko
2012-12-12 18:09 ` Ying Han
2012-12-12 18:34 ` Michal Hocko
2012-12-12 18:42 ` Michal Hocko
2012-12-14 1:06 ` Ying Han
2012-12-14 10:56 ` [PATCH] memcg,vmscan: do not break out targeted reclaim without reclaimed pages Michal Hocko
2012-12-12 19:24 ` [patch v2 3/6] memcg: rework mem_cgroup_iter to use cgroup iterators Michal Hocko
2012-12-14 1:14 ` Ying Han
2012-12-14 12:07 ` Michal Hocko
2012-12-14 23:08 ` Ying Han
2012-12-14 12:37 ` Michal Hocko
2012-11-26 18:47 ` [patch v2 4/6] memcg: simplify mem_cgroup_iter Michal Hocko
2012-11-28 8:52 ` Kamezawa Hiroyuki
2012-11-30 4:09 ` Kamezawa Hiroyuki
2012-12-09 17:01 ` Ying Han
2012-12-11 15:57 ` Michal Hocko
2012-12-11 4:35 ` Ying Han
2012-12-11 16:01 ` Michal Hocko
2012-12-11 22:52 ` Ying Han
2012-11-26 18:47 ` [patch v2 5/6] memcg: further " Michal Hocko
2012-11-30 4:10 ` Kamezawa Hiroyuki
2012-11-30 9:08 ` Glauber Costa
2012-11-30 10:23 ` Michal Hocko
2012-11-26 18:47 ` [patch v2 6/6] cgroup: remove css_get_next Michal Hocko
2012-11-30 4:12 ` Kamezawa Hiroyuki
2012-11-30 8:18 ` Michal Hocko
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