Date: Tue, 7 Jul 2015 19:38:55 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Christoph Lameter <cl@linux.com>,
        Rik van Riel <riel@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 3/3] kmod: Remove unecessary explicit wide CPU affinity
	setting
Message-ID: <20150707173855.GA21133@redhat.com>
References: <1436196821-13962-1-git-send-email-fweisbec@gmail.com> <1436196821-13962-4-git-send-email-fweisbec@gmail.com> <20150707163030.GA16647@redhat.com> <20150707171014.GH20498@lerouge> <20150707173644.GA20422@redhat.com>
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On 07/07, Oleg Nesterov wrote:
>
> On 07/07, Frederic Weisbecker wrote:
> >
> >
> > People who want CPU isolation will likely write
> > /sys/devices/virtual/workqueue/cpumask to a reduced set of CPUs, typically
> > CPU 0 that is used for housekeeping in nohz full.
>
> Well, khelper_wq is not WQ_SYSFS, so I am not sure this is possible.

Please ignore, I see the new "workqueue: Create low-level unbound
workqueues cpumask" commit...


> But this doesn't really matter, people can change cpu affinity. But
> "workqueues are handled by housekeeping CPUs" doesn't look right.
>
> > In fact we should add the code which initialize wq_unbound_cpumask
> > to housekeeping_mask automatically.
>
> Perhaps, but until then the changelog above looks really confusing,
> as if workqueue.c already does this automagically ;)

Yes.

Oleg.

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