Re: [PATCH][2.5] hangcheck-timer

From: Dave Jones (davej@codemonkey.org.uk)
Date: Tue Jan 21 2003 - 12:42:37 EST


On Tue, Jan 21, 2003 at 09:40:02AM -0800, Joel Becker wrote:

> > I'm puzzled. What does this do that softdog.c doesn't ?
>
> First, softdog.c requires userspace interaction. Second, softdog.c
> relies on jiffies. If the system goes out to lunch via udelay() or
> another hardware call that freezes the CPUs for a bit, jiffies does not
> increment. The system could be frozen for two minutes (qla2x00 used to
> do this for 90 seconds) and softdog.c never notices, because jiffies
> hasn't counted a single second during this time.

Ok, seems to make sense now, thanks.
Wouldn't this belong under drivers/char/watchdog too though ?
It seems very 'watchdog-ish' to me.

                Dave

-- 
| Dave Jones.        http://www.codemonkey.org.uk
| SuSE Labs
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