tree f168408f90214873e1fa36733d29f2ba002fae46
parent 408d85441cd5a9bd6bc851d677a10c605ed8db5f
author Nick Piggin <npiggin@suse.de> 1159252288 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1159285728 -0700

[PATCH] oom: reclaim_mapped on oom

Potentially it takes several scans of the lru lists before we can even start
reclaiming pages.

mapped pages, with young ptes can take 2 passes on the active list + one on
the inactive list.  But reclaim_mapped may not always kick in instantly, so it
could take even more than that.

Raise the threshold for marking a zone as all_unreclaimable from a factor of 4
time the pages in the zone to 6.  Introduce a mechanism to force
reclaim_mapped if we've reached a factor 3 and still haven't made progress.

Previously, a customer doing stress testing was able to easily OOM the box
after using only a small fraction of its swap (~100MB).  After the patches, it
would only OOM after having used up all swap (~800MB).

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>