Messages in this thread | | | Date | Fri, 19 Nov 2010 00:34:39 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH] writeback: prevent bandwidth calculation overflow |
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On Fri, Nov 19, 2010 at 12:29:00AM +0800, Peter Zijlstra wrote: > On Fri, 2010-11-19 at 00:06 +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? > > it could, but we chose not to implement the symbol it emits for these > things so as to cause pain.. that was still assuming the world of 32bit > computing was relevant and 64bit divides were expensive ;-)
Good to know that, thanks! So let's avoid it totally :)
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