From: Andrew Morton <akpm00@gmail.com>
To: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: LKML <linux-kernel@vger.kernel.org>,
container ML <containers@lists.linux-foundation.org>,
Paul Menage <paul@paulmenage.org>, Li Zefan <lizf@cn.fujitsu.com>,
Ingo Molnar <mingo@elte.hu>, Miao Xie <miaox@cn.fujitsu.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Tejun Heo <htejun@gmail.com>
Subject: Re: [BUGFIX] cgroup: create a workqueue for cgroup
Date: Fri, 30 Sep 2011 15:30:49 -0700 [thread overview]
Message-ID: <20110930153049.6719a14e.akpm00@gmail.com> (raw)
In-Reply-To: <20110930165452.19c0fdf4.nishimura@mxp.nes.nec.co.jp>
On Fri, 30 Sep 2011 16:54:52 +0900
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> In commit:f90d4118, cpuset_wq, a separate workqueue for cpuset, was introduced
> to avoid a dead lock against cgroup_mutex between async_rebuild_sched_domains()
> and cgroup_tasks_write().
>
> But check_for_release() has a similar problem:
>
> check_for_release()
> schedule_work(release_agent_work)
> cgroup_release_agent()
> mutex_lock(&cgroup_mutex)
>
> And I actually see a lockup which seems to be caused by this problem
> on 2.6.32-131.0.15.el6.x86_64.
Are you sure the bug is still present in current kernels? Perhaps
Tejun's workqueue changes magically made it go away.
>
> ...
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -27,6 +27,8 @@ struct css_id;
>
> extern int cgroup_init_early(void);
> extern int cgroup_init(void);
> +extern void cgroup_wq_init(void);
> +extern void queue_cgroup_work(struct work_struct *work);
> extern void cgroup_lock(void);
> extern int cgroup_lock_is_held(void);
> extern bool cgroup_lock_live_group(struct cgroup *cgrp);
Can we spot the odd man out?
I shall rename queue_cgroup_work() to cgroup_queue_work().
>
> ...
>
next prev parent reply other threads:[~2011-09-30 22:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-30 7:54 Daisuke Nishimura
2011-09-30 22:30 ` Andrew Morton [this message]
2011-10-03 0:22 ` Daisuke Nishimura
2011-10-03 5:19 ` Daisuke Nishimura
2011-10-04 21:10 ` Andrew Morton
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