Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the beginning of CPU_ONLINE

From	Tejun Heo <htejun@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the beginning of CPU_ONLINE
Date	2016-06-21 21:50 +0200
Message-ID	<rMzQl-1Gf-11@gated-at.bofh.it> (permalink)
References	(3 earlier) <rKoFI-6BZ-13@gated-at.bofh.it> <rKLiV-3Wz-7@gated-at.bofh.it> <rMuH0-6Vn-41@gated-at.bofh.it> <rMvWq-7DO-3@gated-at.bofh.it> <rMzQl-1Gf-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, Jun 21, 2016 at 09:37:09PM +0200, Peter Zijlstra wrote:
> Hurm.. So I've applied it, just to get this issue sorted, but I'm not
> entirely sure I like it.
> 
> I think I prefer ego's version because that makes it harder to get stuff
> to run on !active,online cpus. I think we really want to be careful what
> gets to run during that state.

The original patch just did set_cpus_allowed one more time late enough
so that the target kthread (in most cases) doesn't have to go through
fallback rq selection afterwards.  I don't know what the long term
solution is but CPU_ONLINE callbacks should be able to bind kthreads
to the new CPU one way or the other.

Thanks.

-- 
tejun

Thread

Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Tejun Heo <htejun@gmail.com> - 2016-06-15 18:00 +0200
  Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-06-15 21:30 +0200
    Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Tejun Heo <htejun@gmail.com> - 2016-06-16 21:40 +0200
      Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-06-21 16:20 +0200
        Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Tejun Heo <htejun@gmail.com> - 2016-06-21 17:40 +0200
          Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Tejun Heo <htejun@gmail.com> - 2016-06-21 21:50 +0200
            Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Peter Zijlstra <peterz@infradead.org> - 2016-06-21 21:50 +0200
              Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-06-22 07:20 +0200
          Re: [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the  beginning of CPU_ONLINE Peter Zijlstra <peterz@infradead.org> - 2016-06-21 22:50 +0200

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