Re: [PATCH]: exec: avoid propagating PF_NO_SETAFFINITY intouserspace child

From: Oleg Nesterov
Date: Thu Nov 28 2013 - 09:33:39 EST


On 11/28, Peter Zijlstra wrote:
>
> On Thu, Nov 28, 2013 at 02:31:52PM +0100, Oleg Nesterov wrote:
> > I _guess_ usermodehelper_init() should use WQ_SYSFS then, and in this case
> > the user can write to wq_cpumask_store somewhere in /sys/.
>
> WTF is that and why are we creating alternative affinity interfaces when
> sched_setaffinity() is a prefectly fine one?

Because there is no a simple workqueue/thread connection, I guess.

And I do not understand why do you dislike this.

For example. Please note that with the new design we can even kill
khelper_wq and the ugly kmod_thread_locker hack (just in case, I am not
saying that the patch which added kmod_thread_locker was ugly ;).

We can just use one of the system_ WQ_UNBOUND workqueues which has
the "large enough" max_active.

Oleg.

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