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Date: Thu, 28 Nov 2013 13:17:48 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <htejun@gmail.com>, zhang.yi20@zte.com.cn,
        lkml <linux-kernel@vger.kernel.org>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH]: exec: avoid propagating PF_NO_SETAFFINITY into
 userspace child
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On Thu, Nov 28, 2013 at 12:45:42PM +0100, Oleg Nesterov wrote:
> It has? khelper is a workqueue thread, this flag is set by create_worker().
> 
> And it does kernel_thread() (not kthread_create()) so the child gets this
> flag too.

Urgh, but that's still completely wrong. khelper is a singlethread
workqueue, those should be unbound and therefore should not have this
flag set at all.

In fact, I know people want to set affinity on khelper to ensure all the
usermode helper tasks get spawned on the specific system-cpus and leave
the rest of the system unperturbed.