From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: rjw@sisk.pl, linux-kernel@vger.kernel.org, lizefan@huawei.com,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org
Subject: Re: [PATCH 5/7] cgroup_freezer: allow moving tasks in and out of a frozen cgroup
Date: Mon, 22 Oct 2012 17:25:05 -0400 [thread overview]
Message-ID: <20121022212505.GG5951@atj.dyndns.org> (raw)
In-Reply-To: <20121022192506.GA27163@redhat.com>
Hello,
On Mon, Oct 22, 2012 at 09:25:06PM +0200, Oleg Nesterov wrote:
> > @@ -190,12 +201,12 @@ static void freezer_fork(struct task_struct *task)
> > goto out;
> >
> > spin_lock_irq(&freezer->lock);
> > - BUG_ON(freezer->state == CGROUP_FROZEN);
> > -
> > - /* Locking avoids race with FREEZING -> THAWED transitions. */
> > - if (freezer->state == CGROUP_FREEZING)
> > + /*
> > + * @task might have been just migrated into a FROZEN cgroup.
>
> Confused. If it was migrated, then freezer_attach() should take care
> do freeze_task?
Hmmm... there's a window where a task is migrated but ->attach()
hasn't completed yet, so freezer_attach() might not have kicked in
yet. It might not be strictly necessary but I think it's more
consistent this way. No?
Thanks.
--
tejun
next prev parent reply other threads:[~2012-10-22 21:25 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-16 22:28 [PATCHSET cgroup/for-3.8] cgroup_freezer: allow migration regardless of freezer state and update locking Tejun Heo
2012-10-16 22:28 ` [PATCH 1/7] cgroup: cgroup_subsys->fork() should be called after the task is added to css_set Tejun Heo
2012-10-17 8:28 ` Li Zefan
2012-10-18 1:25 ` Li Zefan
2012-10-21 19:11 ` Oleg Nesterov
2012-10-21 19:22 ` Tejun Heo
2012-10-22 18:04 ` Oleg Nesterov
2012-10-22 21:16 ` Tejun Heo
2012-10-23 15:51 ` Oleg Nesterov
2012-10-24 19:04 ` Tejun Heo
2012-10-25 17:42 ` Oleg Nesterov
2012-12-20 5:25 ` Herton Ronaldo Krzesinski
2012-12-28 21:22 ` [PATCH] cgroup: remove unused dummy cgroup_fork_callbacks() Tejun Heo
2012-10-16 22:28 ` [PATCH 2/7] freezer: add missing mb's to freezer_count() and freezer_should_skip() Tejun Heo
2012-10-22 17:44 ` Oleg Nesterov
2012-10-22 21:13 ` Tejun Heo
2012-10-23 15:39 ` Oleg Nesterov
2012-10-24 18:57 ` Tejun Heo
2012-10-25 16:39 ` [PATCH 0/1] (Was: freezer: add missing mb's to freezer_count() and freezer_should_skip()) Oleg Nesterov
2012-10-25 16:39 ` [PATCH 1/1] freezer: change ptrace_stop/do_signal_stop to use freezable_schedule() Oleg Nesterov
2012-10-25 17:18 ` Tejun Heo
2012-10-25 17:34 ` Oleg Nesterov
2012-10-25 17:36 ` Tejun Heo
2012-10-26 17:45 ` [PATCH v2 0/1] " Oleg Nesterov
2012-10-26 17:46 ` [PATCH v2 1/1] " Oleg Nesterov
2012-10-26 17:52 ` Tejun Heo
2012-10-26 18:01 ` Oleg Nesterov
2012-10-26 21:14 ` Rafael J. Wysocki
2012-10-26 21:29 ` Rafael J. Wysocki
2012-10-26 21:29 ` Tejun Heo
2012-10-28 0:16 ` Rafael J. Wysocki
2012-10-27 22:22 ` Ben Hutchings
2012-10-28 13:45 ` Oleg Nesterov
2012-10-16 22:28 ` [PATCH 3/7] cgroup_freezer: make it official that writes to freezer.state don't fail Tejun Heo
2012-10-16 22:28 ` [PATCH 4/7] cgroup_freezer: don't stall transition to FROZEN for PF_NOFREEZE or PF_FREEZER_SKIP tasks Tejun Heo
2012-10-22 18:34 ` Oleg Nesterov
2012-10-22 21:18 ` Tejun Heo
2012-10-23 15:55 ` Oleg Nesterov
2012-10-24 19:06 ` Tejun Heo
2012-10-25 17:12 ` [PATCH 0/1] (Was: cgroup_freezer: don't stall transition to FROZEN for PF_NOFREEZE or PF_FREEZER_SKIP tasks) Oleg Nesterov
2012-10-25 17:12 ` [PATCH 1/1] freezer: exec should clear PF_NOFREEZE along with PF_KTHREAD Oleg Nesterov
2012-10-25 17:20 ` Tejun Heo
2012-10-25 17:37 ` Oleg Nesterov
2012-10-25 17:37 ` Tejun Heo
2012-10-25 20:13 ` Rafael J. Wysocki
2012-10-16 22:28 ` [PATCH 5/7] cgroup_freezer: allow moving tasks in and out of a frozen cgroup Tejun Heo
2012-10-22 19:25 ` Oleg Nesterov
2012-10-22 21:25 ` Tejun Heo [this message]
2012-10-23 16:14 ` Oleg Nesterov
2012-10-16 22:28 ` [PATCH 6/7] cgroup_freezer: prepare update_if_frozen() for locking change Tejun Heo
2012-10-16 22:28 ` [PATCH 7/7] cgroup_freezer: don't use cgroup_lock_live_group() Tejun Heo
2012-10-17 19:16 ` [PATCHSET cgroup/for-3.8] cgroup_freezer: allow migration regardless of freezer state and update locking Matt Helsley
2012-10-18 21:14 ` Tejun Heo
2012-10-18 22:21 ` Matt Helsley
2012-10-18 22:35 ` Tejun Heo
2012-10-18 23:47 ` Matt Helsley
2012-10-19 0:01 ` Tejun Heo
2012-10-19 1:29 ` Matt Helsley
2012-10-19 20:02 ` Tejun Heo
2012-10-19 16:54 ` Rafael J. Wysocki
2012-10-19 20:04 ` Tejun Heo
2012-10-21 19:18 ` Oleg Nesterov
2012-10-21 19:24 ` Tejun Heo
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