mm: vmscan: evaluate the watermarks against the correct classzone
authorMel Gorman <mgorman@suse.de>
Fri, 8 Jul 2011 22:39:39 +0000 (15:39 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 9 Jul 2011 04:14:43 +0000 (21:14 -0700)
commitda175d06b437093f93109ba9e5efbe44dfdf9409
tree04bbed7c41347e3614690947c66f87e8e38a6051
parentd7868dae893c83c50c7824bc2bc75f93d114669f
mm: vmscan: evaluate the watermarks against the correct classzone

When deciding if kswapd is sleeping prematurely, the classzone is taken
into account but this is different to what balance_pgdat() and the
allocator are doing.  Specifically, the DMA zone will be checked based on
the classzone used when waking kswapd which could be for a GFP_KERNEL or
GFP_HIGHMEM request.  The lowmem reserve limit kicks in, the watermark is
not met and kswapd thinks it's sleeping prematurely keeping kswapd awake in
error.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Pádraig Brady <P@draigBrady.com>
Tested-by: Pádraig Brady <P@draigBrady.com>
Tested-by: Andrew Lutomirski <luto@mit.edu>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmscan.c