Messages in this thread |  | | | Date | Fri, 19 Nov 2010 00:22:22 +0800 | | From | Wu Fengguang <> | | Subject | Re: [PATCH] writeback: prevent bandwidth calculation overflow |
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On Fri, Nov 19, 2010 at 12:06:52AM +0800, Wu Fengguang wrote: > On Fri, Nov 19, 2010 at 12:02:01AM +0800, Peter Zijlstra wrote: > > On Thu, 2010-11-18 at 23:44 +0800, Wu Fengguang wrote: > > > + pause = HZ * pages_dirtied / (bw + 1); > > > > Shouldn't that be using something like div64_u64 ? > > OK, but a dumb question: gcc cannot handle this implicitly?
Hmm, I'm tempting to do
pause = HZ * pages_dirtied / ((unsigned long)bw + 1);
because here "bw" is guaranteed to be smaller than ULONG_MAX.
Thanks, Fengguang
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