Messages in this thread | | | Date | Fri, 19 Nov 2004 11:59:03 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: page fault scalability patch V11 [0/7]: overview |
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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.
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