mm: vmscan: fix inappropriate zone congestion clearing
authorJohannes Weiner <hannes@cmpxchg.org>
Thu, 6 Dec 2012 20:23:25 +0000 (15:23 -0500)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 8 Dec 2012 16:41:18 +0000 (08:41 -0800)
commited23ec4f0a510528e0ffe415f9394107418ae854
treee124564fc3796c67098399fdd15a48240f3430f5
parent684c9aaebbb0ea3a9954d605d4908e650659e7db
mm: vmscan: fix inappropriate zone congestion clearing

commit c702418f8a2f ("mm: vmscan: do not keep kswapd looping forever due
to individual uncompactable zones") removed zone watermark checks from
the compaction code in kswapd but left in the zone congestion clearing,
which now happens unconditionally on higher order reclaim.

This messes up the reclaim throttling logic for zones with
dirty/writeback pages, where zones should only lose their congestion
status when their watermarks have been restored.

Remove the clearing from the zone compaction section entirely.  The
preliminary zone check and the reclaim loop in kswapd will clear it if
the zone is considered balanced.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmscan.c