Re: page fault scalability patch V11 [0/7]: overview
From: Linus Torvalds
Date: Fri Nov 19 2004 - 15:06:53 EST
On Fri, 19 Nov 2004, Christoph Lameter wrote:
>
> Note that I have posted two other approaches of dealing with the rss problem:
You could also make "rss" be a _signed_ integer per-thread.
When unmapping a page, you decrement one of the threads that shares the mm
(doesn't matter which - which is why the per-thread rss may go negative),
and when mapping a page you increment it.
Then, anybody who actually wants a global rss can just iterate over
threads and add it all up. If you do it under the mmap_sem, it's stable,
and if you do it outside the mmap_sem it's imprecise but stable in the
long term (ie errors never _accumulate_, like the non-atomic case will
do).
Does anybody care enough? Maybe, maybe not. It certainly sounds a hell of
a lot better than the periodic scan.
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/