From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Glauber Costa <glommer@parallels.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Michal Hocko <mhocko@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
LKML <linux-kernel@vger.kernel.org>,
Cgroups <cgroups@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 1/8] cgroup: implement cgroup_is_ancestor()
Date: Mon, 8 Apr 2013 08:39:42 -0700 [thread overview]
Message-ID: <20130408153942.GC3021@htj.dyndns.org> (raw)
In-Reply-To: <51627DBB.5050005@huawei.com>
Hello, Li.
On Mon, Apr 08, 2013 at 04:20:11PM +0800, Li Zefan wrote:
> +/**
> + * cgroup_is_ancestor - test "root" cgroup is an ancestor of "child"
> + * @child: the cgroup to be tested.
> + * @root: the cgroup supposed to be an ancestor of the child.
Please explain locking in the comment. (I know it only requires both
cgroups to be accessible but being explicit is nice.)
> + * Returns true if "root" is an ancestor of "child" in its hierarchy.
> + */
> +bool cgroup_is_ancestor(struct cgroup *child, struct cgroup *root)
s/root/ancestor/
> +{
> + int depth = child->depth;
> +
> + if (depth < root->depth)
> + return false;
> +
> + while (depth-- != root->depth)
> + child = child->parent;
Just walk up till it meets the ancestor or reaches root. Why bother
with depth?
Thanks.
--
tejun
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next prev parent reply other threads:[~2013-04-08 15:39 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-08 8:19 [PATCH 0/8] memcg, cgroup: kill css_id Li Zefan
2013-04-08 8:20 ` [PATCH 1/8] cgroup: implement cgroup_is_ancestor() Li Zefan
2013-04-08 14:47 ` Michal Hocko
2013-04-08 15:57 ` Tejun Heo
2013-04-08 16:33 ` Michal Hocko
2013-04-08 18:03 ` Michal Hocko
2013-04-08 21:36 ` Tejun Heo
2013-04-09 6:42 ` Michal Hocko
2013-04-08 15:39 ` Tejun Heo [this message]
2013-04-09 3:21 ` Kamezawa Hiroyuki
2013-04-09 3:29 ` Li Zefan
2013-04-08 8:20 ` [PATCH 2/8] cgroup: implement cgroup_from_id() Li Zefan
2013-04-08 15:43 ` Tejun Heo
2013-04-09 3:12 ` Li Zefan
2013-04-08 15:48 ` Tejun Heo
2013-04-09 3:56 ` Kamezawa Hiroyuki
2013-04-09 4:08 ` Kamezawa Hiroyuki
2013-04-08 8:21 ` [PATCH 3/8] memcg: convert to use cgroup_is_ancestor() Li Zefan
2013-04-09 3:58 ` Kamezawa Hiroyuki
2013-04-09 6:49 ` Michal Hocko
2013-04-08 8:21 ` [PATCH 4/8] memcg: convert to use cgroup_from_id() Li Zefan
2013-04-08 14:53 ` Michal Hocko
2013-04-09 3:00 ` Li Zefan
2013-04-09 3:59 ` Kamezawa Hiroyuki
2013-04-08 8:22 ` [PATCH 5/8] memcg: convert to use cgroup->id Li Zefan
2013-04-08 14:57 ` Michal Hocko
2013-04-09 3:02 ` Li Zefan
2013-04-09 6:49 ` Michal Hocko
2013-04-09 4:02 ` Kamezawa Hiroyuki
2013-04-08 8:22 ` [PATCH 6/8] memcg: fail to create cgroup if the cgroup id is too big Li Zefan
2013-04-08 15:01 ` Michal Hocko
2013-04-08 8:23 ` [PATCH 7/8] memcg: don't use css_id any more Li Zefan
2013-04-08 15:01 ` Michal Hocko
2013-04-09 4:11 ` Kamezawa Hiroyuki
2013-04-08 8:23 ` [PATCH 8/8] cgroup: kill css_id Li Zefan
2013-04-08 15:51 ` Tejun Heo
2013-04-08 14:37 ` [PATCH 0/8] memcg, " Michal Hocko
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