From: Michal Hocko <mhocko@suse.cz>
To: Tejun Heo <tj@kernel.org>
Cc: lizefan@huawei.com, rjw@sisk.pl,
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: Wed, 7 Nov 2012 16:38:35 +0100 [thread overview]
Message-ID: <20121107153835.GC4131@dhcp22.suse.cz> (raw)
In-Reply-To: <20121106203154.GV30069@mtj.dyndns.org>
On Tue 06-11-12 12:31:54, Tejun Heo wrote:
> 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?
Yes, definitely. We are currently iterating by css->id which is, ehm,
impractical. Having a deterministic tree walk is definitely a plus.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2012-11-07 15:38 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
2012-11-07 15:38 ` Michal Hocko [this message]
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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