[PATCH -mm] Freezer: migration_thread should not be freezable (was: Re: [linux-pm] Re: 2.6.22-rc3-mm1)

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Thursday, 31 May 2007 21:58, Rafael J. Wysocki wrote:
> On Thursday, 31 May 2007 17:29, Michal Piotrowski wrote:
> > Hi,
> > 
> > Andrew Morton napisał(a):
> > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22-rc3/2.6.22-rc3-mm1/
> > > 
> > 
> > FYI suspend to disk doesn't work anymore on my box, system hangs after "Suspending console(s)" message.
> > 
> > [  186.297753] Shrinking memory...  \b-\b\\b|\b/\b-\b\\b|\bdone (113064 pages freed)
> > [  187.841914] Freed 452256 kbytes in 1.54 seconds (293.67 MB/s)
> > [  187.847730] Suspending console(s)
> > 
> > http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/2.6.22-rc3-mm1/console.log
> > http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/2.6.22-rc3-mm1/mm-config
> 
> Hmm, that might be a couple of things, actually.
> 
> To see if the patches directly related to hibernation/suspend cause this, can
> you please test 2.6.22-rc3 with the patch series at
> 
> http://www.sisk.pl/kernel/hibernation_and_suspend/2.6.22-rc3/patches/
> 
> applied?

Ahem, I broke it. :-(

Andrew, the following fix is needed on top of
freezer-make-kernel-threads-nonfreezable-by-default.patch

---
From: Rafael J. Wysocki <rjw@sisk.pl>

migration_thread should not be freezable, or it will break hibernation and
suspend on SMP.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 kernel/sched.c |    3 ---
 1 file changed, 3 deletions(-)

Index: linux-2.6.22-rc3/kernel/sched.c
===================================================================
--- linux-2.6.22-rc3.orig/kernel/sched.c
+++ linux-2.6.22-rc3/kernel/sched.c
@@ -5157,13 +5157,10 @@ static int migration_thread(void *data)
 	BUG_ON(rq->migration_thread != current);
 
 	set_current_state(TASK_INTERRUPTIBLE);
-	set_freezable();
 	while (!kthread_should_stop()) {
 		struct migration_req *req;
 		struct list_head *head;
 
-		try_to_freeze();
-
 		spin_lock_irq(&rq->lock);
 
 		if (cpu_is_offline(cpu)) {