From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Colin Cross <ccross@android.com>
Cc: Len Brown <lenb@kernel.org>, Len Brown <len.brown@intel.com>,
Kevin Hilman <khilman@ti.com>,
Santosh Shilimkar <santosh.shilimkar@ti.com>,
linux-kernel@vger.kernel.org,
Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH] cpuidle: coupled: fix sleeping while atomic in cpu notifier
Date: Thu, 26 Jul 2012 22:16:43 +0200 [thread overview]
Message-ID: <201207262216.43665.rjw@sisk.pl> (raw)
In-Reply-To: <201207262215.06372.rjw@sisk.pl>
On Thursday, July 26, 2012, Rafael J. Wysocki wrote:
> On Thursday, July 26, 2012, Colin Cross wrote:
> > On Thu, Jul 26, 2012 at 12:55 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > > On Wednesday, July 25, 2012, Colin Cross wrote:
> > >> The cpu hotplug notifier gets called in both atomic and non-atomic
> > >> contexts, it is not always safe to lock a mutex. Filter out all events
> > >> except the six necessary ones, which are all sleepable, before taking
> > >> the mutex.
> > >
> > > I wonder what mutual exclusion mechanis we rely on when the mutex is not taken?
> >
> > We don't need any mutual exclusion because the notifier returns immediately.
>
> Don't we need to disable preemption even?
Sorry, scratch that. It returns NOTIFY_OK if we're not going to take the
mutex.
Thanks,
Rafael
next prev parent reply other threads:[~2012-07-26 20:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-25 21:20 [PATCH] cpuidle: coupled: fix sleeping while atomic in cpu notifier Colin Cross
2012-07-26 7:25 ` Shilimkar, Santosh
2012-07-26 22:54 ` Shilimkar, Santosh
2012-07-26 19:55 ` Rafael J. Wysocki
2012-07-26 19:51 ` Colin Cross
2012-07-26 20:15 ` Rafael J. Wysocki
2012-07-26 20:16 ` Rafael J. Wysocki [this message]
2012-07-31 15:43 ` Srivatsa S. Bhat
2012-07-31 18:27 ` Colin Cross
2012-08-01 5:59 ` Srivatsa S. Bhat
2012-08-07 22:15 ` Rafael J. Wysocki
2012-08-08 0:54 ` Colin Cross
2012-08-15 20:16 ` Rafael J. Wysocki
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