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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: "Dmitry Adamushko" <dmitry.adamushko@gmail.com>
Subject: Re: [Regression] 2.6.24-git3: Major annoyance during suspend/hibernation on x86-64 (bisected)
Date: Sat, 2 Feb 2008 00:26:53 +0100
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Cc: "Ingo Molnar" <mingo@elte.hu>, "Peter Zijlstra" <a.p.zijlstra@chello.nl>,
       "Steven Rostedt" <srostedt@redhat.com>,
       "Andrew Morton" <akpm@linux-foundation.org>,
       "Linus Torvalds" <torvalds@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>
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On Saturday, 2 of February 2008, Dmitry Adamushko wrote:
> On 01/02/2008, Ingo Molnar <mingo@elte.hu> wrote:
> >
> > * Dmitry Adamushko <dmitry.adamushko@gmail.com> wrote:
> >
> > > > I've observed delays from ~3 s. up to ~8 s. (out of ~20 tests) so
> > > > the 10s. delay of msleep_interruptible() might be related but I'm
> > > > still looking for the reason why this fix helps (and what goes wrong
> > > > with the current code).
> > >
> > > heh... it's pretty obvious indeed. What's msleep_interruptible() is
> > > all about? :-)
> > >
> > > "sleep waiting for signals"
> > >
> > > so the 'watchdog' thread gets woken up
> > >
> > > [ as a result of cpu_callback(action = CPU_DEAD) --> kthread_stop() ]
> > >
> > > just to be immediately scheduled out again for as long as the
> > > remaining timeout > 0.
> > >
> > > So it should work if we substitute msleep_interruptible() with
> > > schedule_timeout_interruptible().
> >
> > Doh. Could someone with ths problem please test the patch below, does it
> > do the trick?
> 
> yeah, I was already on a half-way to check it out.
> 
> It does fix a problem for me.
> 
> Don't forget to take along these 2 fixes from Peter's patch:
> 
> - fix break usage in do_each_thread() { } while_each_thread().
> - fix the hotplug switch stmt, a fall-through case was broken.
> 
> 
> Rafael, does your system still hangs? I'd expect, yes -- as
> effectively this fix is not that different from Peter's one when it
> comes to suspend-case.

I haven't tested it yet, but I don't expect it to hang, as the Peter's patch
started to work for me.  I'm going to test it in a while.

Thanks,
Rafael