Re: [patch 11/13] s390: instruction processing damage handling.

Martin Schwidefsky
2006-04-28T09:24:41Z

On Fri, 2006-04-28 at 10:39 +0200, Heiko Carstens wrote:
> > > +++ linux-2.6-patched/drivers/s390/s390mach.c 2006-04-24 16:47:28.000000000 +0200
> > ...
> > > +#define MAX_IPD_TIME (5 * 60 * 100 * 1000) /* 5 minutes */
> >
> > I'm no s390 expert, but shouldn't the above use something like HZ?
>
> Using HZ here feels just wrong to me. MAX_IPD_TIME has nothing to do with the
> timer frequency. In this case it's used to tell if there were 30 machine
> checks within the last 5 minutes (in a usec granularity). It's just by
> accident that this could be expressed using HZ.
> (5 * 60 * USEC_PER_SEC) would probably look better...

Using HZ would be wrong. The check that uses MAX_IPD_TIME compares it
against the result of a get_clock() call. That uses the TOD Clock
directly, there is no dependency on HZ.

--
blue skies,
Martin.

Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH

"Reality continues to ruin my life." - Calvin.