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From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [cgroup/task_lock] INFO: suspicious RCU usage.
Date: Tue, 25 Feb 2014 10:06:36 -0500	[thread overview]
Message-ID: <20140225150636.GF26788@htj.dyndns.org> (raw)
In-Reply-To: <530C8615.4020004@huawei.com>

Hello, Li.

On Tue, Feb 25, 2014 at 08:01:25PM +0800, Li Zefan wrote:
...
> >> So, this is from removing task_lock from task_css_set_check() and
> >> adding rcu_read_lock() in cpuset_cpus_allowed() should fix it.
> > 
> > Yeah, rcu_read_lock() should be sufficient.
> > 
> >> I'm
> >> not sure how much of task_lock() locking we currently have in cpuset
> >> is actually necessary tho.  Shouldn't we be able to do most with just
> >> callback_mutex, if not cpuset_mutex?  Li, any ideas?
> >>
> > 
> > task_lock() is also used to protect task->mems_allowed. I'll see if we
> > can get rid of most (if not all) task_lock() lockings in cpuset.
> > 
> 
> After a quick lock, I think except the one in cpuset_change_task_nodemask(), all
> other task_lock() lockings can be replace by rcu_readlock().

I committed the original series as-is.  Can you please post follow-up
patches to update cpuset locking?

Thanks.

-- 
tejun

      reply	other threads:[~2014-02-25 15:06 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-21  2:16 Fengguang Wu
2014-02-21 15:40 ` Tejun Heo
2014-02-25  8:51   ` Li Zefan
2014-02-25 12:01     ` Li Zefan
2014-02-25 15:06       ` Tejun Heo [this message]

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