Messages in this thread |  | | Date | Mon, 11 Sep 2000 14:51:47 -0300 (BRST) | From | Rik van Riel <> | Subject | Re: [PATCH] Page aging for 2.4.0-test8 |
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On Mon, 11 Sep 2000, Neil Schemenauer wrote: > On Mon, Sep 11, 2000 at 01:12:32PM -0300, Rik van Riel wrote: > > Your idea /heavily/ penalises libc and executable pages by aging them > > more often than anonymous pages... > > I don't think I age anonymous pages any more than any other type > of page.
Think again.
You're aging them both in try_to_swap_out() /and/ in shrink_mmap().
> Perhaps you are saying that shared pages should recieve some > bonus?
No. I'm saying shared pages should have the accessed bits propagated and be only aged once. I know we can't handle this right for 2.4, but for 2.5 I hope to use physical-page based page aging to get this one right...
> That is a different issue and it is handled naturally with my > patch. If shared pages are actually used then PageTouch() will > be called on them more often.
This is /not/ the case. Think of a page from libc, which is mapped by 30 processes. Now imagine that page is being heavily used and was used by 5 processes since we scanned it the last time.
With your patch we'd age the page down 25 (!!) times and only age it up 5 times. This is clearly not what you want for a page which was used by 5 different processes since the last time we scanned it...
regards,
Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000
http://www.conectiva.com/ http://www.surriel.com/
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