From: Andrew Morton <akpm@linux-foundation.org>
To: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Mike Galbraith <bitbucket@online.de>,
Thomas Gleixner <tglx@linutronix.de>,
Gilad Ben-Yossef <gilad@benyossef.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Mike Frysinger <vapier@gentoo.org>
Subject: Re: [PATCH] kmod: Run usermodehelpers only on cpus allowed for kthreadd
Date: Thu, 17 Oct 2013 12:23:44 -0700 [thread overview]
Message-ID: <20131017122344.39d55db97c3923131bdf2831@linux-foundation.org> (raw)
In-Reply-To: <00000141c36b03b6-2f9bd3de-d153-4359-901f-084aeb4c040d-000000@email.amazonses.com>
On Wed, 16 Oct 2013 22:37:52 +0000 Christoph Lameter <cl@linux.com> wrote:
> > > - /* We can run anywhere, unlike our parent keventd(). */
> > > - set_cpus_allowed_ptr(current, cpu_all_mask);
> > > + /* We can run anywhere kthreadd can run */
> >
> > This is a poor comment - it explains "what" (which was utterly obvious)
> > but doesn't explain "why". The reader will want to know *why*
> > call_usermodehelper() only runs on kthreadd CPUs, but we didn't tell
> > him.
>
> We'd like to have the ability to avoid running usermodehelper on certain
> cpus to avoid cpu holdoff situations? Would that we an acceptable
> explanation?
>
> Or restricting kthreadd will also restrict usermodehelper spawning to
> allow control for all spawned kernel threads?
Both, please ;)
next prev parent reply other threads:[~2013-10-17 19:23 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-16 14:44 Christoph Lameter
2013-10-16 21:13 ` Andrew Morton
2013-10-16 22:37 ` Christoph Lameter
2013-10-17 19:23 ` Andrew Morton [this message]
2013-11-07 16:43 ` [PATCH] kmod: Run usermodehelpers only on cpus allowed for kthreadd V2 Christoph Lameter
2013-11-07 22:50 ` Frederic Weisbecker
2013-11-08 15:06 ` Christoph Lameter
2013-11-08 16:31 ` Frederic Weisbecker
2013-11-08 17:05 ` Christoph Lameter
2013-11-08 19:12 ` Frederic Weisbecker
2013-11-08 19:52 ` Christoph Lameter
2013-11-08 20:06 ` Frederic Weisbecker
2014-04-08 20:57 ` Andrew Morton
2014-04-08 21:56 ` Frederic Weisbecker
2013-10-17 13:55 ` [PATCH] kmod: Run usermodehelpers only on cpus allowed for kthreadd Frederic Weisbecker
2013-10-17 15:24 ` Christoph Lameter
2013-10-17 16:07 ` Frederic Weisbecker
2013-10-17 17:50 ` Andrew Morton
2013-10-17 18:24 ` Christoph Lameter
2013-10-17 22:27 ` Frederic Weisbecker
2013-10-20 18:00 ` Christoph Lameter
2013-10-17 18:23 ` Christoph Lameter
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