From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: "Frederic Weisbecker" <fweisbec@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Cgroups <cgroups@vger.kernel.org>, "Mel Gorman" <mgorman@suse.de>,
"David Rientjes" <rientjes@google.com>,
"缪 勰" <miaox@cn.fujitsu.com>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [RFC][PATCH] cgroup: fix race between fork and cgroup freezing
Date: Thu, 8 Mar 2012 10:26:22 -0800 [thread overview]
Message-ID: <20120308182622.GC25508@google.com> (raw)
In-Reply-To: <4F587199.6050404@cn.fujitsu.com>
Hello, Li, Frederic.
On Thu, Mar 08, 2012 at 04:45:13PM +0800, Li Zefan wrote:
> +static void freezer_post_fork(struct cgroup_subsys *ss,
> + struct task_struct *task)
> +{
> + struct freezer *freezer;
> +
> + cgroup_lock();
> +
> + freezer = task_freezer(task);
> + if (!freezer->css.cgroup->parent)
> + goto out;
> +
> + spin_lock_irq(&freezer->lock);
> + if (freezer->state != CGROUP_THAWED)
> + freeze_task(task);
> + spin_unlock_irq(&freezer->lock);
> +out:
> + cgroup_unlock();
> +}
Urgh... this is requiring policy implementations to synchronize with
problem caused by cgroup core optimization and it's so very subtle.
IMHO, this definitely should be contained in cgroup core and in a very
confined form even inside cgroup core.
Any other ideas?
Thanks.
--
tejun
next prev parent reply other threads:[~2012-03-08 18:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-08 8:45 [RFC][PATCH] cgroup: fix race between fork and cgroup freezing Li Zefan
2012-03-08 18:26 ` Tejun Heo [this message]
2012-03-09 6:26 ` Li Zefan
2012-03-09 16:53 ` Tejun Heo
2012-03-12 9:02 ` Li Zefan
2012-03-12 16:10 ` Tejun Heo
2012-03-19 13:44 ` Frederic Weisbecker
2012-03-19 15:05 ` Frederic Weisbecker
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