linux-kernel - Re: [PATCH] workqueue: Restore cpus_allowed mask for sleeping workqueue rescue threads

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Date:	Fri, 2 Sep 2011 09:29:17 +0900
From:	Tejun Heo <tj@...nel.org>
To:	Ripduman Sohan <ripduman.sohan@...cam.ac.uk>
Cc:	linux-kernel@...r.kernel.org, peterz@...radead.org
Subject: Re: [PATCH] workqueue: Restore cpus_allowed mask for sleeping
 workqueue rescue threads

Hello,

On Thu, Sep 01, 2011 at 02:36:33PM +0100, Ripduman Sohan wrote:
> Rescuer threads may be migrated (and are bound) to particular CPUs when
> active.  However, the allowed_cpus mask is not restored when they return
> to sleep rendering inconsistent the presented and actual set of CPUs the
> process may potentially run on.  This patch fixes this oversight by
> recording the allowed_cpus mask for rescuer threads when it enters the
> rescuer_thread() main loop and restoring it every time the thread sleeps.

Hmmm... so, currently, rescuer is left bound to the last cpu it worked
on.  Why is this a problem?

Thanks.

-- 
tejun
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