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From: Tejun Heo <tj@kernel.org>
To: lizefan@huawei.com, mhocko@suse.cz, rjw@sisk.pl
Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	fweisbec@gmail.com
Subject: Re: [PATCH 3/9] cgroup: implement generic child / descendant walk macros
Date: Tue, 6 Nov 2012 12:31:54 -0800	[thread overview]
Message-ID: <20121106203154.GV30069@mtj.dyndns.org> (raw)
In-Reply-To: <1351931915-1701-4-git-send-email-tj@kernel.org>

On Sat, Nov 03, 2012 at 01:38:29AM -0700, Tejun Heo wrote:
> Currently, cgroup doesn't provide any generic helper for walking a
> given cgroup's children or descendants.  This patch adds the following
> three macros.
> 
> * cgroup_for_each_child() - walk immediate children of a cgroup.
> 
> * cgroup_for_each_descendant_pre() - visit all descendants of a cgroup
>   in pre-order tree traversal.
> 
> * cgroup_for_each_descendant_post() - visit all descendants of a
>   cgroup in post-order tree traversal.
> 
> All three only require the user to hold RCU read lock during
> traversal.  Verifying that each iterated cgroup is online is the
> responsibility of the user.  When used with proper synchronization,
> cgroup_for_each_descendant_pre() can be used to propagate config
> updates to descendants in reliable way.  See comments for details.

Michal, Li, how does this look to you?  Would this be okay for memcg
too?  Li, do you think the comment on cgroup_for_each_descendant_pre()
is correct?

Thanks.

-- 
tejun

  reply	other threads:[~2012-11-06 20:32 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-03  8:38 [PATCHSET cgroup/for-3.8] cgroup_freezer: implement proper hierarchy support Tejun Heo
2012-11-03  8:38 ` [PATCH 1/9] cgroup: add cgroup_subsys->post_create() Tejun Heo
2012-11-05 13:42   ` Glauber Costa
2012-11-05 18:02     ` [RFC] cgroup: deprecate clone_children Tejun Heo
2012-11-05 19:17       ` Serge Hallyn
2012-11-05 19:26         ` Tejun Heo
2012-11-07 15:25   ` [PATCH 1/9] cgroup: add cgroup_subsys->post_create() Michal Hocko
2012-11-07 17:02     ` Tejun Heo
2012-11-07 17:15   ` [PATCH 1/9 v2] " Tejun Heo
2012-11-07 17:40     ` Michal Hocko
2012-11-08  2:59     ` Kamezawa Hiroyuki
2012-11-08 19:07   ` [PATCH 1/9 v3] " Tejun Heo
2012-11-09  9:09     ` Li Zefan
2012-11-09  9:09     ` Li Zefan
2012-11-09 11:09     ` Daniel Wagner
2012-11-09 17:22       ` Tejun Heo
2012-11-10  1:35         ` Glauber Costa
2012-11-12 13:04         ` Daniel Wagner
2012-11-03  8:38 ` [PATCH 2/9] cgroup: Use rculist ops for cgroup->children Tejun Heo
2012-11-07 15:30   ` Michal Hocko
2012-11-08  3:01   ` Kamezawa Hiroyuki
2012-11-09  9:10   ` Li Zefan
2012-11-03  8:38 ` [PATCH 3/9] cgroup: implement generic child / descendant walk macros Tejun Heo
2012-11-06 20:31   ` Tejun Heo [this message]
2012-11-07 15:38     ` Michal Hocko
2012-11-07 16:54   ` Michal Hocko
2012-11-07 17:01     ` Tejun Heo
2012-11-07 17:49       ` Michal Hocko
2012-11-08  3:21   ` Kamezawa Hiroyuki
2012-11-08  9:50   ` Michal Hocko
2012-11-08 17:15     ` Tejun Heo
2012-11-08 17:59   ` [PATCH 3/9 v2] " Tejun Heo
2012-11-09  9:13     ` Li Zefan
2012-11-03  8:38 ` [PATCH 4/9] cgroup_freezer: trivial cleanups Tejun Heo
2012-11-08  3:24   ` Kamezawa Hiroyuki
2012-11-08  9:53   ` Michal Hocko
2012-11-03  8:38 ` [PATCH 5/9] cgroup_freezer: prepare freezer_change_state() for full hierarchy support Tejun Heo
2012-11-08  4:25   ` Kamezawa Hiroyuki
2012-11-08  9:56   ` Michal Hocko
2012-11-03  8:38 ` [PATCH 6/9] cgroup_freezer: make freezer->state mask of flags Tejun Heo
2012-11-08  4:37   ` Kamezawa Hiroyuki
2012-11-08  4:42     ` Tejun Heo
2012-11-08  5:00       ` Kamezawa Hiroyuki
2012-11-08 14:38         ` Tejun Heo
2012-11-08 10:39   ` Michal Hocko
2012-11-08 14:39     ` Tejun Heo
2012-11-08 14:47       ` Michal Hocko
2012-11-03  8:38 ` [PATCH 7/9] cgroup_freezer: introduce CGROUP_FREEZING_[SELF|PARENT] Tejun Heo
2012-11-08  4:42   ` Kamezawa Hiroyuki
2012-11-08  4:45     ` Tejun Heo
2012-11-08  4:56       ` Kamezawa Hiroyuki
2012-11-08 14:41         ` Tejun Heo
2012-11-08 12:47   ` Michal Hocko
2012-11-08 14:42     ` Tejun Heo
2012-11-03  8:38 ` [PATCH 8/9] cgroup_freezer: add ->post_create() and ->pre_destroy() and track online state Tejun Heo
2012-11-08  4:48   ` Kamezawa Hiroyuki
2012-11-08 15:41     ` Tejun Heo
2012-11-08 13:23   ` Michal Hocko
2012-11-08 17:17     ` Tejun Heo
2012-11-03  8:38 ` [PATCH 9/9] cgroup_freezer: implement proper hierarchy support Tejun Heo
2012-11-07 11:00   ` Michal Hocko
2012-11-07 16:31     ` Tejun Heo
2012-11-07 16:39   ` [PATCH 9/9 v2] " Tejun Heo
2012-11-08 14:08     ` Michal Hocko
2012-11-08 14:18       ` Tejun Heo
2012-11-08 15:20         ` Michal Hocko
2012-11-08 15:29           ` Tejun Heo
2012-11-08 15:57             ` Michal Hocko
2012-11-08 17:57   ` [PATCH 9/9 v3] " Tejun Heo
2012-11-08 18:02     ` Michal Hocko
2012-11-08 18:04       ` Tejun Heo
2012-11-08 18:08         ` Michal Hocko
2012-11-08 18:01 ` [PATCHSET cgroup/for-3.8] " Tejun Heo
2012-11-09 17:15 ` Tejun Heo

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