[PATCH] sched: Fix the irqtime code to deal with u64 wraps

[peterz@infradead.org (Peter Zijlstra)]

On Fri, 2010-12-10 at 21:23 -0500, Nicolas Pitre wrote:
> On Fri, 10 Dec 2010, Peter Zijlstra wrote:
> 
> > OK, so here's the latest version, using fancy __this_cpu thingies.
> > 
> > I started a new thread since the old one was quite unwieldy.
> > 
> > Now, admittedly this patch is a tad large, esp for -rc5. So either we
> > need lots of Reviewed-by and such or I need to shrink this patch
> > somehow.
> > 
> > 
> > ---
> > Subject: sched: Fix the irqtime code to deal with u64 wraps
> > From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Date: Thu Dec 09 14:15:34 CET 2010
> > 
> > ARM systems have a 32bit sched_clock() [ which needs to be fixed ],
> > but this exposed a bug in the irq_time code as well, it doesn't deal
> > with wraps at all.
> [...]
> 
> That would be more close to reality if you stated "Some ARM systems have 
> a 32bit sched_clock() [" above.  Most ARM systems in use today have a 
> sched_clock() with more than 32 bits, like 55 bits or so.

OK, I'll rephrase.