[patch] softlockup: fix false positives on CONFIG_NOHZ

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



* Ingo Molnar <[email protected]> wrote:

> these can be fixed, but:
> 
> > This will introduce an up-to-one-second delay in responding to 
> > kthread_should_stop().  Is that bad?
> 
> grumble, it's bad. I guess David is right that this should be fixed 
> the right way ;-) So the above patch cannot go in.

Thomas found the right fix. David, could you try the fix below, does it 
fix those false positives on your nohz Niagara cores?

	Ingo

---------------->
Subject: softlockup: fix false positives on CONFIG_NOHZ
From: Thomas Gleixner <[email protected]>

David Miller reported soft lockup false-positives that trigger
on NOHZ due to CPUs idling for more than 10 seconds.

The solution is touch the softlockup watchdog when we return from
idle. (by definition we are not 'locked up' when we were idle)

 http://bugzilla.kernel.org/show_bug.cgi?id=9409

Reported-by: David Miller <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
 kernel/time/tick-sched.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux/kernel/time/tick-sched.c
===================================================================
--- linux.orig/kernel/time/tick-sched.c
+++ linux/kernel/time/tick-sched.c
@@ -133,6 +133,8 @@ void tick_nohz_update_jiffies(void)
 	if (!ts->tick_stopped)
 		return;
 
+	touch_softlockup_watchdog();
+
 	cpu_clear(cpu, nohz_cpu_mask);
 	now = ktime_get();
 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux