Re: [PATCH v2] [watchdog] combine nmi_watchdog and softlockup

From: Frederic Weisbecker
Date: Fri Apr 16 2010 - 12:24:26 EST


On Fri, Apr 16, 2010 at 12:14:01PM -0400, Don Zickus wrote:
> On Fri, Apr 16, 2010 at 05:32:12PM +0200, Frederic Weisbecker wrote:
> > > I'll try to implement this. Any objections if I combined hardlockup and
> > > softlockup with per cpu watchdog_warn and have bit masks for HARDLOCKUP
> > > and SOFTLOCKUP? I hate to just waste per cpu space for this.
> >
> >
> >
> > Hmm, a hardlockup can come in after a softlockup.
>
> Let me re-explain what I meant. It was meant to do double duty. The
> softlockup code only checks the SOFTLOCKUP bit and the hardlockup only
> ever checks the HARDLOCKUP bit.
>
> ie if get_cpu_var(watchdog_warn) && HARDLOCKUP { return; }


Ah right.



>
> > Don't worry too much about memory: usually the more you have cpu,
> > the more you have memory :)
> > Plus this is debugging code, not something supposed to be enabled
> > in production.
>
> Well depends on your POV. In RHEL we enable both NMI_WATCHDOG and
> SOFTLOCKUP on production systems (and we have customers that are
> thankful for that :-) ).


Ok :)

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