On Tue, 2008-06-10 at 17:14 -0400, Rik van Riel wrote:
Well, it does speed up the check for mlocked pages in page_reclaimable()
[now page_evictable()?] as we don't have to walk the reverse map to
determine that a page is mlocked. In many places where we currently
test page_reclaimable(), we really don't want to and maybe can't walk
the reverse map.
Unless you're evisioning even larger rework, the PG_unevictable flag
[formerly PG_noreclaim, right?] is analogous to PG_active. It's only
set when the page is on the corresponding lru list or being held
isolated from it, temporarily. See isolate_lru_page() and
putback_lru_page() and users thereof--such as mlock_vma_page(). Again,
I have seen what changes you're making here, so maybe that's all
changing. But, currently, PG_unevictable would not be a replacement for
PG_mlocked.
Anyway, let's see what you come up with before we tackle this.
Couple of related items:
+ 26-rc5-mm1 + a small fix to the double unlock_page() in
shrink_page_list() has been running for a couple of hours on my 32G,
16cpu ia64 numa platform w/o error. Seems to have survived the merge
into -mm, despite the issues Andrew has raised.
+ on same platform, Mel Gorman's mminit debug code is reporting that
we're using 22 page flags with Noreclaim, Mlock and PAGEFLAGS_EXTENDED
configured.
Lee
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