Re: broken suspend (sched related) [Was: 2.6.24-rc4-mm1]

Ingo Molnar
2007-12-07T15:12:32Z

* Jiri Slaby <jirislaby@gmail.com> wrote:

> On 12/05/2007 06:17 AM, Andrew Morton wrote:
> > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.24-rc4/2.6.24-rc4-mm1/
>
> > git-sched.patch
>
> breaks suspend here since -rc3-mm2. More precisely, this one:
> softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks
>
> 2.6.24-rc4-mm1 minus this one works just fine. Otherwise disks stop, graphics
> stops and then it hangs not powering down.
>
> Core 2 Duo, SMP kernel, voluntary preempt, 250 HZ, SLUB, 64 bit.
>
> Ideas?

thanks for tracking it down. Does the patch below help?

Ingo

---
kernel/softlockup.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

Index: linux/kernel/softlockup.c
===================================================================
--- linux.orig/kernel/softlockup.c
+++ linux/kernel/softlockup.c
@@ -101,7 +101,11 @@ void softlockup_tick(void)

now = get_timestamp(this_cpu);

- /* Warn about unreasonable delays: */
+ /* Wake up the high-prio watchdog task every second: */
+ if (now > (touch_timestamp + 1))
+ wake_up_process(per_cpu(watchdog_task, this_cpu));
+
+ /* Warn about unreasonable 10+ seconds delays: */
if (now <= (touch_timestamp + softlockup_thresh))
return;

@@ -214,7 +218,7 @@ static int watchdog(void *__bind_cpu)
*/
while (!kthread_should_stop()) {
touch_softlockup_watchdog();
- msleep_interruptible(10000);
+ schedule();

/*
* Only do the hung-tasks check on one CPU: