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 9/9] cgroup_freezer: implement proper hierarchy support
Date: Wed, 7 Nov 2012 12:00:57 +0100 [thread overview]
Message-ID: <20121107110024.GA4143@dhcp22.suse.cz> (raw)
In-Reply-To: <1351931915-1701-10-git-send-email-tj@kernel.org>
On Sat 03-11-12 01:38:35, Tejun Heo wrote:
[...]
> diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
> index 4f12d31..3262537 100644
> --- a/kernel/cgroup_freezer.c
> +++ b/kernel/cgroup_freezer.c
[...]
> @@ -320,14 +388,39 @@ static void freezer_apply_state(struct freezer *freezer, bool freeze,
> * @freezer: freezer of interest
> * @freeze: whether to freeze or thaw
> *
> - * Freeze or thaw @cgroup according to @freeze.
> + * Freeze or thaw @freezer according to @freeze. The operations are
> + * recursive - all descendants of @freezer will be affected.
> */
> static void freezer_change_state(struct freezer *freezer, bool freeze)
> {
> + struct cgroup *pos;
> +
> /* update @freezer */
> spin_lock_irq(&freezer->lock);
> freezer_apply_state(freezer, freeze, CGROUP_FREEZING_SELF);
> spin_unlock_irq(&freezer->lock);
> +
> + /*
> + * Update all its descendants in pre-order traversal. Each
> + * descendant will try to inherit its parent's FREEZING state as
> + * CGROUP_FREEZING_PARENT.
> + */
> + rcu_read_lock();
> + cgroup_for_each_descendant_pre(pos, freezer->css.cgroup) {
> + struct freezer *pos_f = cgroup_freezer(pos);
> + struct freezer *parent = parent_freezer(freezer);
This doesn't seem right. Why are we interested in freezer->parent here
at all? We should either care about freezer->state & CGROUP_FREEZING or
parent = parent_freezer(pos_f), right?
> +
> + /*
> + * Our update to @parent->state is already visible which is
> + * all we need. No need to lock @parent. For more info on
> + * synchronization, see freezer_post_create().
> + */
> + spin_lock_irq(&pos_f->lock);
> + freezer_apply_state(pos_f, parent->state & CGROUP_FREEZING,
> + CGROUP_FREEZING_PARENT);
> + spin_unlock_irq(&pos_f->lock);
> + }
> + rcu_read_unlock();
> }
>
> static int freezer_write(struct cgroup *cgroup, struct cftype *cft,
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2012-11-07 11:01 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
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 [this message]
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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