Messages in this thread | | | Subject | Re: [patch 5/5] Optimize page_mkclean_one | From | Martin Schwidefsky <> | Date | Mon, 02 Jul 2007 09:07:26 +0200 |
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On Sun, 2007-07-01 at 15:27 +0200, Peter Zijlstra wrote: > > But I could easily be overlooking something: Peter will recall. > > /me tries to get his brain up to speed after the OLS closing party :-)
Oh-oh, the Black Thorn party :-)
> I did both pte_dirty and pte_write because I was extra careful. One > _should_ imply the other, but since we'll be clearing both, I thought it > prudent to also check both.
Just ran a little experiment: I've added a simple WARN_ON(ret == 0) to page_mkclean after the page_test_dirty() check to see if there are cases where the page is dirty and all ptes are read-only. A little stress run including massive swap did not print a single warning.
> I will have to think on this a little more, but I'm currently of the > opinion that the optimisation is not correct. But I'll have a thorough > look at s390 again when I get home.
I think the patch is correct, although I beginning to doubt that is has any effect.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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