Date: Thu, 6 Nov 2014 05:53:57 +1100
From: Anton Blanchard <anton@samba.org>
To: Don Zickus <dzickus@redhat.com>
Cc: uobergfe@redhat.com, drjones@redhat.com, akpm@linux-foundation.org,
        linux-kernel@vger.kernel.org, Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog
Message-ID: <20141106055357.530e1458@kryten>
In-Reply-To: <20141105145356.GL135937@redhat.com>
References: <20141105093420.1c7500d8@kryten>
	<20141105145356.GL135937@redhat.com>
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Sender: linux-kernel-owner@vger.kernel.org


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
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