vmscan: check high watermark after shrink zone
authorMinchan Kim <minchan.kim@gmail.com>
Fri, 5 Mar 2010 21:41:45 +0000 (13:41 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 6 Mar 2010 19:26:24 +0000 (11:26 -0800)
commit45973d74fd3b1e3e16c025b688a725c7653b1443
tree79b002bf8da8807a4d82314426611ca2109f83e8
parent59e99e5b9706867f18d4a36c1e4645fbaacbec2e
vmscan: check high watermark after shrink zone

Kswapd checks that zone has sufficient pages free via zone_watermark_ok().

If any zone doesn't have enough pages, we set all_zones_ok to zero.
!all_zone_ok makes kswapd retry rather than sleeping.

I think the watermark check before shrink_zone() is pointless.  Only after
kswapd has tried to shrink the zone is the check meaningful.

Move the check to after the call to shrink_zone().

[akpm@linux-foundation.org: fix comment, layout]
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmscan.c