Re: page fault scalability patch V11 [0/7]: overview

From: Linus Torvalds
Date: Fri Nov 19 2004 - 21:01:34 EST




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.

Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/