Messages in this thread | | | Date | Mon, 22 Nov 2004 13:06:03 -0500 | From | Bill Davidsen <> | Subject | Re: page fault scalability patch V11 [0/7]: overview |
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Linus Torvalds wrote: > > On Sat, 20 Nov 2004, Nick Piggin wrote: > >>The per thread rss may wrap (maybe not 64-bit counters), but even so, >>the summation over all threads should still end up being correct I >>think. > > > Yes. As long as the total rss fits in an int, it doesn't matter if any of > them wrap. Addition is still associative in twos-complement arithmetic > even in the presense of overflows. > > If you actually want to make it proper standard C, I guess you'd have to > make the thing unsigned, which gives you the mod-2**n guarantees even if > somebody were to ever make a non-twos-complement machine.
I think other stuff breaks as well, I think I saw you post some example code using something like (a & -a) or similar within the last few months. Fortunately neither 1's comp or BCD are likeliy to return in hardware. Big-end vs. little-end is still an issue, though.
-- -bill davidsen (davidsen@tmr.com) "The secret to procrastination is to put things off until the last possible moment - but no longer" -me
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