tree 78f55c2d3019d1811b5447cae130c0f647916a37
parent 64cdd548ffe26849d4cd113ac640f60606063b14
author Johannes Weiner <hannes@cmpxchg.org> 1231281557 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1231286340 -0800

mm: more likely reclaim MADV_SEQUENTIAL mappings

File pages mapped only in sequentially read mappings are perfect reclaim
canditates.

This patch makes these mappings behave like weak references, their pages
will be reclaimed unless they have a strong reference from a normal
mapping as well.

It changes the reclaim and the unmap path where they check if the page has
been referenced.  In both cases, accesses through sequentially read
mappings will be ignored.

Benchmark results from KOSAKI Motohiro:

    http://marc.info/?l=linux-mm&m=122485301925098&w=2

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>