Messages in this thread |  | | | Subject | Re: [PATCH 2/2] sched: Fix "divide error: 0000" in find_busiest_group | | From | Peter Zijlstra <> | | Date | Tue, 19 Jul 2011 23:18:10 +0200 |
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On Tue, 2011-07-19 at 14:58 -0600, Terry Loftin wrote: > Add a check to sched_avg_update() to detect and reset age_stamp if the > clock value has wrapped. Because __cycles_2_ns() includes an offset > to account for start up time, the clock may not wrap to zero, so use > the current clock value instead.
So you're running on a platform (unspecified) where we use a raw sched_clock() that is buggy. Again, you're fixing symptoms not causes.
> Signed-off-by: Terry Loftin <terry.loftin@hp.com> > Signed-off-by: Bob Montgomery <bob.montgomery@hp.com> > --- > diff --git a/kernel/sched.c b/kernel/sched.c > index 18d38e4..b39cae1 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -1256,6 +1256,8 @@ static void sched_avg_update(struct rq *rq) > { > s64 period = sched_avg_period(); > > + if (unlikely(rq->age_stamp > rq->clock)) > + rq->age_stamp = rq->clock; > while ((s64)(rq->clock - rq->age_stamp) > period) { > /* > * Inline assembly required to prevent the compiler
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