Messages in this thread | | | From | Nikita Danilov <> | Date | Mon, 1 Mar 2004 14:10:26 +0300 | Subject | Re: 2.4.23aa2 (bugfixes and important VM improvements for the high end) |
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Rik van Riel writes:
[...]
> > Duh, I forgot all about the rotate_reclaimable_page() stuff. > That may well fix all problems 2.6 would have otherwise had > in this area. > > I really hope we won't need anything like the O(1) VM stuff > in 2.6, since that would leave me more time to work on other > cool stuff (like resource management ;)).
Page-out from end of the inactive list is not efficient, because pages are submitted for IO in more or less random order and this results in a lot of seeks. Test-case: replace ->writepage() with
int foofs_writepage(struct page *page) { SetPageDirty(page); unlock_page(page); return 0; }
and run
$ time cp /tmpfs/huge-data-set /foofs
File systems (and anonymous memory) want clustered write-out and VM designs with separate write-out queue (like O(1) VM) are better suited for this.
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