Re: [PATCH] Use deltas to replace atomic inc
From: Christoph Lameter <hidden>
Date: 2005-08-22 15:24:50
On Mon, 22 Aug 2005, Hugh Dickins wrote:
(Your deltas seem sensible, but hard to place the reaccumulation: I worry that you may be taking page_table_lock more just for that.)
The page_table_lock is taken using a spin_trylock. Its skipped if contended.
Just to say, please do remove the anon_rss incrementation from inside page_add_anon_rmap if it helps you: I put it there as a lazy way of avoiding a bigger patch, but it would be much nicer to count separate file_rss and anon_rss, with /proc showing the sum of the two as rss.
Hmm. Thats a big projects. Lets first focus on getting the deltas right.
Especially since it's anonymous that most concerns you: the present setup is biased against anonymous since it's counted in two fields - perhaps no issue once you've rearranged, but not good for atomics.
There will be no atomics once the deltas are in.
If you don't get there first, I do intend in due course to replace rss and anon_rss by file_rss and anon_rss (and try to sort out the the tlb mmu gathering stuff, which is a little odd, in dealing with rss but not with anon_rss).
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