Re: [PATCH 1/2] NMI watchdog: add support to enable and disableIOAPIC NMI

From: Randy Dunlap
Date: Wed Oct 29 2008 - 20:51:15 EST


On Wed, 29 Oct 2008 16:39:19 -0400 Aristeu Rozanski wrote:

> > > > This patch adds support to enable/disable IOAPIC NMI watchdog in runtime via
> > > > procfs.
> > >
> > > Some info on how to use this, what to write(?) to what file(?) in procfs
> > > would be Very Good to have.
> >
> > I gather this is an extension to the existing interface already covering
> > the local APIC NMI watchdog, which surely ;) must have been documented at
> > the time it was added. If it wasn't, then we cannot require it now as a
> > prerequisite to accept this patch, although such documentation would be
> > desirable as a separate submission.
> What about (if OK, I'll resubmit in a different thread with proper format):
>
> ---
> Documentation/nmi_watchdog.txt | 5 +++++
> 1 file changed, 5 insertions(+)
>
> --- linus-2.6.orig/Documentation/nmi_watchdog.txt 2008-10-24 11:41:30.000000000 -0400
> +++ linus-2.6/Documentation/nmi_watchdog.txt 2008-10-29 16:38:12.000000000 -0400
> @@ -69,6 +69,11 @@ to the overall system performance.
> On x86 nmi_watchdog is disabled by default so you have to enable it with
> a boot time parameter.
>
> +It's possible to disable the NMI watchdog in run-time by writing "0" to
> +/proc/sys/kernel/nmi_watchdog. Writing "1" to the same file will re-enable
> +the NMI watchdog. Notice that you still need to use "nmi_watchdog=" parameter
> +in boot time.
> +
> NOTE: In kernels prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally
> on x86 SMP boxes.

OK. Or update Documentation/filesystems/proc.txt::nmi_watchdog
(now that I have found it).

---
~Randy
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