* Confusing behaviour with /proc/sys/kernel/nmi_watchdog
@ 2014-11-04 22:34 Anton Blanchard
2014-11-05 10:26 ` Andrew Jones
2014-11-05 14:53 ` Don Zickus
0 siblings, 2 replies; 7+ messages in thread
From: Anton Blanchard @ 2014-11-04 22:34 UTC (permalink / raw)
To: uobergfe, drjones, dzickus, akpm; +Cc: linux-kernel
Hi,
commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled by
default") provided a way for the kernel to disable the hard lockup
detector at runtime.
I'm using it on ppc64 but notice some weird behaviour with the
nmi_watchdog procfs variable. At boot, that the hard lockup
detector appears to be enabled even when we disable it via
watchdog_enable_hardlockup_detector(false):
# cat /proc/sys/kernel/nmi_watchdog
1
I have to echo 0 to it then echo 1 again to enable it.
Anton
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog 2014-11-04 22:34 Confusing behaviour with /proc/sys/kernel/nmi_watchdog Anton Blanchard @ 2014-11-05 10:26 ` Andrew Jones 2015-01-21 3:39 ` Anton Blanchard 2014-11-05 14:53 ` Don Zickus 1 sibling, 1 reply; 7+ messages in thread From: Andrew Jones @ 2014-11-05 10:26 UTC (permalink / raw) To: Anton Blanchard; +Cc: uobergfe, dzickus, akpm, linux-kernel On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote: > > Hi, > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled by > default") provided a way for the kernel to disable the hard lockup > detector at runtime. > > I'm using it on ppc64 but notice some weird behaviour with the > nmi_watchdog procfs variable. At boot, that the hard lockup > detector appears to be enabled even when we disable it via > watchdog_enable_hardlockup_detector(false): > > # cat /proc/sys/kernel/nmi_watchdog > 1 > > I have to echo 0 to it then echo 1 again to enable it. > > Anton Hi Anton, Yes, the nmi watchdog proc variables are currently a bit confusing. Uli has posted a series to clear all that up though. Please see https://lkml.org/lkml/2014/10/17/340 drew ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog 2014-11-05 10:26 ` Andrew Jones @ 2015-01-21 3:39 ` Anton Blanchard 2015-01-21 10:52 ` Andrew Jones 0 siblings, 1 reply; 7+ messages in thread From: Anton Blanchard @ 2015-01-21 3:39 UTC (permalink / raw) To: Andrew Jones; +Cc: uobergfe, dzickus, akpm, linux-kernel, Michael Ellerman Hi Andrew, > On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote: > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled > > by default") provided a way for the kernel to disable the hard > > lockup detector at runtime. > > > > I'm using it on ppc64 but notice some weird behaviour with the > > nmi_watchdog procfs variable. At boot, that the hard lockup > > detector appears to be enabled even when we disable it via > > watchdog_enable_hardlockup_detector(false): > > > > # cat /proc/sys/kernel/nmi_watchdog > > 1 > > > > I have to echo 0 to it then echo 1 again to enable it. > > > > Anton > > Hi Anton, > > Yes, the nmi watchdog proc variables are currently a bit > confusing. Uli has posted a series to clear all that up > though. Please see > > https://lkml.org/lkml/2014/10/17/340 Any progress on this? I'm rebasing our hardware NMI patch for ppc64 and notice the strange behaviour is still in mainline. Anton ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog 2015-01-21 3:39 ` Anton Blanchard @ 2015-01-21 10:52 ` Andrew Jones 2015-01-21 14:30 ` Don Zickus 0 siblings, 1 reply; 7+ messages in thread From: Andrew Jones @ 2015-01-21 10:52 UTC (permalink / raw) To: Anton Blanchard; +Cc: uobergfe, dzickus, akpm, linux-kernel, Michael Ellerman On Wed, Jan 21, 2015 at 02:39:42PM +1100, Anton Blanchard wrote: > Hi Andrew, > > > On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote: > > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled > > > by default") provided a way for the kernel to disable the hard > > > lockup detector at runtime. > > > > > > I'm using it on ppc64 but notice some weird behaviour with the > > > nmi_watchdog procfs variable. At boot, that the hard lockup > > > detector appears to be enabled even when we disable it via > > > watchdog_enable_hardlockup_detector(false): > > > > > > # cat /proc/sys/kernel/nmi_watchdog > > > 1 > > > > > > I have to echo 0 to it then echo 1 again to enable it. > > > > > > Anton > > > > Hi Anton, > > > > Yes, the nmi watchdog proc variables are currently a bit > > confusing. Uli has posted a series to clear all that up > > though. Please see > > > > https://lkml.org/lkml/2014/10/17/340 > > Any progress on this? I'm rebasing our hardware NMI patch for ppc64 and > notice the strange behaviour is still in mainline. > Hi Anton, I'm not aware of anything blocking this series, but maybe I missed something. Andrew Morton and Don Zickus are the ones to ask. Andrew? Don? Thanks, drew ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog 2015-01-21 10:52 ` Andrew Jones @ 2015-01-21 14:30 ` Don Zickus 0 siblings, 0 replies; 7+ messages in thread From: Don Zickus @ 2015-01-21 14:30 UTC (permalink / raw) To: Andrew Jones Cc: Anton Blanchard, uobergfe, akpm, linux-kernel, Michael Ellerman On Wed, Jan 21, 2015 at 11:52:51AM +0100, Andrew Jones wrote: > On Wed, Jan 21, 2015 at 02:39:42PM +1100, Anton Blanchard wrote: > > Hi Andrew, > > > > > On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote: > > > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled > > > > by default") provided a way for the kernel to disable the hard > > > > lockup detector at runtime. > > > > > > > > I'm using it on ppc64 but notice some weird behaviour with the > > > > nmi_watchdog procfs variable. At boot, that the hard lockup > > > > detector appears to be enabled even when we disable it via > > > > watchdog_enable_hardlockup_detector(false): > > > > > > > > # cat /proc/sys/kernel/nmi_watchdog > > > > 1 > > > > > > > > I have to echo 0 to it then echo 1 again to enable it. > > > > > > > > Anton > > > > > > Hi Anton, > > > > > > Yes, the nmi watchdog proc variables are currently a bit > > > confusing. Uli has posted a series to clear all that up > > > though. Please see > > > > > > https://lkml.org/lkml/2014/10/17/340 > > > > Any progress on this? I'm rebasing our hardware NMI patch for ppc64 and > > notice the strange behaviour is still in mainline. > > > > Hi Anton, > > I'm not aware of anything blocking this series, but maybe I missed > something. Andrew Morton and Don Zickus are the ones to ask. Andrew? > Don? Hi Drew, I poked Andrew again. I believe he is the person who usually takes my patches in. Cheers, Don ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog 2014-11-04 22:34 Confusing behaviour with /proc/sys/kernel/nmi_watchdog Anton Blanchard 2014-11-05 10:26 ` Andrew Jones @ 2014-11-05 14:53 ` Don Zickus 2014-11-05 18:53 ` Anton Blanchard 1 sibling, 1 reply; 7+ messages in thread From: Don Zickus @ 2014-11-05 14:53 UTC (permalink / raw) To: Anton Blanchard; +Cc: uobergfe, drjones, akpm, linux-kernel On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote: > > Hi, > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled by > default") provided a way for the kernel to disable the hard lockup > detector at runtime. > > I'm using it on ppc64 but notice some weird behaviour with the > nmi_watchdog procfs variable. At boot, that the hard lockup > detector appears to be enabled even when we disable it via > watchdog_enable_hardlockup_detector(false): > > # cat /proc/sys/kernel/nmi_watchdog > 1 > > I have to echo 0 to it then echo 1 again to enable it. Hi Anton, I believe Andrew answered the question for you, it's a WIP and we have patches to clean that up. I don't see ppc64 watchdog support in arch/powerpc, is that something you are working with on implementing? Cheers, Don ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog 2014-11-05 14:53 ` Don Zickus @ 2014-11-05 18:53 ` Anton Blanchard 0 siblings, 0 replies; 7+ messages in thread From: Anton Blanchard @ 2014-11-05 18:53 UTC (permalink / raw) To: Don Zickus; +Cc: uobergfe, drjones, akpm, linux-kernel, Michael Ellerman Hi Don, > > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled > > by default") provided a way for the kernel to disable the hard > > lockup detector at runtime. > > > > I'm using it on ppc64 but notice some weird behaviour with the > > nmi_watchdog procfs variable. At boot, that the hard lockup > > detector appears to be enabled even when we disable it via > > watchdog_enable_hardlockup_detector(false): > > > > # cat /proc/sys/kernel/nmi_watchdog > > 1 > > > > I have to echo 0 to it then echo 1 again to enable it. > > I believe Andrew answered the question for you, it's a WIP and we have > patches to clean that up. Thanks, yes good to see it being worked on. > I don't see ppc64 watchdog support in arch/powerpc, is that something > you are working with on implementing? I've submitted it over on linuxppc-dev: http://patchwork.ozlabs.org/patch/406802/ Anton ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-01-21 14:30 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-11-04 22:34 Confusing behaviour with /proc/sys/kernel/nmi_watchdog Anton Blanchard 2014-11-05 10:26 ` Andrew Jones 2015-01-21 3:39 ` Anton Blanchard 2015-01-21 10:52 ` Andrew Jones 2015-01-21 14:30 ` Don Zickus 2014-11-05 14:53 ` Don Zickus 2014-11-05 18:53 ` Anton Blanchard
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