From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Tejun Heo <tj@kernel.org>
Cc: "Russell King - ARM Linux" <linux@arm.linux.org.uk>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: try_to_freeze() called with IRQs disabled on ARM
Date: Thu, 25 Aug 2011 01:15:25 +0200 [thread overview]
Message-ID: <201108250115.25987.rjw@sisk.pl> (raw)
In-Reply-To: <20110823223518.GI2803@mtj.dyndns.org>
On Wednesday, August 24, 2011, Tejun Heo wrote:
> On Wed, Aug 24, 2011 at 12:17:03AM +0200, Tejun Heo wrote:
> > if (freezing() && IRQ disabled) {
> > bust on IRQ;
> > try_to_freeze();
> > replug IRQ;
> > }
> >
> > But, that can't be right. The current code isn't triggering warning
> > from scheduler code, right? If the above is the case, it should be
> > triggering that. What am I missing?
>
> I think the refrigerator() code was actually doing that through
> spin_[un]lock_irq(), so it was accidentally masking the problem. It
> definitely seems to need fixing.
>
> Anyways, for now, we can do two things,
>
> 1. if (freezing()) { irq_save; try_to_freeze(); irq_restore; } w/ BIG
> FAT UGLY comment.
>
> 2. Drop might_sleep() from try_to_freeze(). Moving it to
> refrigerator() wouldn't help much. It would just trigger more
> sporadically during freeze, which is arguably worse than now.
>
> I'd prefer #1 given that it documents the breakage while also
> restoring the IRQ state afterwards FWIW.
OK, I'm fine with 1.
Thanks,
Rafael
WARNING: multiple messages have this Message-ID (diff)
From: rjw@sisk.pl (Rafael J. Wysocki)
To: linux-arm-kernel@lists.infradead.org
Subject: try_to_freeze() called with IRQs disabled on ARM
Date: Thu, 25 Aug 2011 01:15:25 +0200 [thread overview]
Message-ID: <201108250115.25987.rjw@sisk.pl> (raw)
In-Reply-To: <20110823223518.GI2803@mtj.dyndns.org>
On Wednesday, August 24, 2011, Tejun Heo wrote:
> On Wed, Aug 24, 2011 at 12:17:03AM +0200, Tejun Heo wrote:
> > if (freezing() && IRQ disabled) {
> > bust on IRQ;
> > try_to_freeze();
> > replug IRQ;
> > }
> >
> > But, that can't be right. The current code isn't triggering warning
> > from scheduler code, right? If the above is the case, it should be
> > triggering that. What am I missing?
>
> I think the refrigerator() code was actually doing that through
> spin_[un]lock_irq(), so it was accidentally masking the problem. It
> definitely seems to need fixing.
>
> Anyways, for now, we can do two things,
>
> 1. if (freezing()) { irq_save; try_to_freeze(); irq_restore; } w/ BIG
> FAT UGLY comment.
>
> 2. Drop might_sleep() from try_to_freeze(). Moving it to
> refrigerator() wouldn't help much. It would just trigger more
> sporadically during freeze, which is arguably worse than now.
>
> I'd prefer #1 given that it documents the breakage while also
> restoring the IRQ state afterwards FWIW.
OK, I'm fine with 1.
Thanks,
Rafael
next prev parent reply other threads:[~2011-08-24 23:13 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-23 15:19 try_to_freeze() called with IRQs disabled on ARM Mark Brown
2011-08-23 15:19 ` Mark Brown
2011-08-23 15:43 ` Russell King - ARM Linux
2011-08-23 15:43 ` Russell King - ARM Linux
2011-08-23 22:08 ` Rafael J. Wysocki
2011-08-23 22:08 ` Rafael J. Wysocki
2011-08-23 21:51 ` Rafael J. Wysocki
2011-08-23 21:51 ` Rafael J. Wysocki
2011-08-23 21:53 ` Tejun Heo
2011-08-23 21:53 ` Tejun Heo
2011-08-23 22:00 ` Russell King - ARM Linux
2011-08-23 22:00 ` Russell King - ARM Linux
2011-08-23 22:08 ` Tejun Heo
2011-08-23 22:08 ` Tejun Heo
2011-08-23 22:13 ` Russell King - ARM Linux
2011-08-23 22:13 ` Russell King - ARM Linux
2011-08-23 22:17 ` Tejun Heo
2011-08-23 22:17 ` Tejun Heo
2011-08-23 22:35 ` Tejun Heo
2011-08-23 22:35 ` Tejun Heo
2011-08-24 23:15 ` Rafael J. Wysocki [this message]
2011-08-24 23:15 ` Rafael J. Wysocki
2011-08-25 12:14 ` Russell King - ARM Linux
2011-08-25 12:14 ` Russell King - ARM Linux
2011-08-25 12:17 ` Tejun Heo
2011-08-25 12:17 ` Tejun Heo
2011-08-25 12:25 ` Russell King - ARM Linux
2011-08-25 12:25 ` Russell King - ARM Linux
2011-08-25 12:35 ` Tejun Heo
2011-08-25 12:35 ` Tejun Heo
2011-08-25 13:04 ` Russell King - ARM Linux
2011-08-25 13:04 ` Russell King - ARM Linux
2011-08-25 13:09 ` Tejun Heo
2011-08-25 13:09 ` Tejun Heo
2011-08-25 14:55 ` Russell King - ARM Linux
2011-08-25 14:55 ` Russell King - ARM Linux
2011-08-26 14:44 ` Arnd Bergmann
2011-08-26 14:44 ` Arnd Bergmann
2011-09-01 13:41 ` Ulrich Weigand
2011-09-01 13:41 ` Ulrich Weigand
2011-09-01 14:00 ` Russell King - ARM Linux
2011-09-01 14:00 ` Russell King - ARM Linux
2011-09-02 14:47 ` Ulrich Weigand
2011-09-02 14:47 ` Ulrich Weigand
2011-09-02 17:22 ` Russell King - ARM Linux
2011-09-02 17:22 ` Russell King - ARM Linux
2011-09-02 17:40 ` Ulrich Weigand
2011-09-02 17:40 ` Ulrich Weigand
2011-09-02 17:48 ` Russell King - ARM Linux
2011-09-02 17:48 ` Russell King - ARM Linux
2011-09-16 10:31 ` Martin Schwidefsky
2011-09-16 10:31 ` Martin Schwidefsky
2011-09-27 17:45 ` Ulrich Weigand
2011-09-27 17:45 ` Ulrich Weigand
2011-08-30 20:58 ` Mark Brown
2011-08-30 20:58 ` Mark Brown
2011-08-30 21:10 ` Russell King - ARM Linux
2011-08-30 21:10 ` Russell King - ARM Linux
2012-06-26 16:39 ` Mandeep Singh Baines
2012-06-26 16:39 ` Mandeep Singh Baines
2012-06-26 17:16 ` Russell King - ARM Linux
2012-06-26 17:16 ` Russell King - ARM Linux
2011-08-23 22:13 ` Rafael J. Wysocki
2011-08-23 22:13 ` Rafael J. Wysocki
2011-08-25 11:37 ` Mark Brown
2011-08-25 11:37 ` Mark Brown
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