Messages in this thread | | | Date | Mon, 13 Aug 2012 13:48:21 +0200 | From | Stanislaw Gruszka <> | Subject | Re: [PATCH] sched: fix divide by zero at {thread_group,task}_times |
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On Wed, Aug 08, 2012 at 10:08:20PM +0200, Peter Zijlstra wrote: > On Wed, 2012-08-08 at 21:50 +0200, Mike Galbraith wrote: > > 32bit built do_div() > > and div64_u64() both sucked equally compared to 64bit > > /me peeks at div64_u64 fallback implementation and sees why, it still > does a single div, it does some neat fls tricks. > > Ok, no point in avoiding this then.. > > I did the below little edit, no point in mixing the old and new > primitives.. those __force things annoy me, but I guess otherwise we'll > upset sparse.
Yeah, __force is needed for sparse, since we marked cputime_t with __nocast (by commit 648616343cdbe904c585a6c12e323d3b3c72e46f, which btw looks like very nice cleanup at whole).
> Index: linux-2.6/kernel/sched/core.c > =================================================================== > --- linux-2.6.orig/kernel/sched/core.c > +++ linux-2.6/kernel/sched/core.c > @@ -3149,7 +3149,7 @@ static cputime_t scale_utime(cputime_t u > temp *= (__force u64) utime; > > if (sizeof(cputime_t) == 4) > - do_div(temp, (__force u32) total); > + temp = div_u64(temp, (__force u32) total); > else > temp = div64_u64(temp, (__force u64) total);
Is this or will be queued (I do not see it queued anywhere)? Or should I repost with above change?
Thanks Stanislaw
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