Re: [PATCH] watchdog: Make sure the watchdog thread gets CPU onloaded system

From: Peter Zijlstra
Date: Thu Mar 15 2012 - 07:06:50 EST


On Thu, 2012-03-15 at 12:00 +0100, Peter Zijlstra wrote:
> On Wed, 2012-03-14 at 18:45 -0700, Mandeep Singh Baines wrote:
> > You could make MAX_RT_PRIO greater than MAX_USER_RT_PRIO but that
> > might
> > have some impact on real-time applications. A simple one-line patch:
> >
> > - #define MAX_RT_PRIO MAX_USER_RT_PRIO
> > + #define MAX_RT_PRIO (MAX_USER_RT_PRIO + 1)
> >
> > would prevent user-space from causing a false lockup detection.
>
> We're so not going to muck with the fifo priorities just for this stupid
> soft watchdog,.. I already hate that I can't disable the piece of crap,
> making it more involved is just really not going to happen.

And before people start to whinge about that, all the soft watchdog
issues I've seen fly by the past year or so all were bugs in the
watchdog itself, I can't actually remember it flagging a real problem.

The NMI watchdog otoh works like a charm for me and regularly helps out
when I done stupid.

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