Check zone->all_unreclaimable in all_unreclaimable(), otherwise the
kernel may hang up, because shrink_zones() will do nothing, but
all_unreclaimable() will say, that zone has reclaimable pages.

do_try_to_free_pages()
	shrink_zones()
		 for_each_zone
			if (zone->all_unreclaimable)
				continue
	if !all_unreclaimable(zonelist, sc)
		return 1

__alloc_pages_slowpath()
retry:
	did_some_progress = do_try_to_free_pages(page)
	...
	if (!page && did_some_progress)
		retry;

Signed-off-by: Andrey Vagin <avagin@openvz.org>
---
 mm/vmscan.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6771ea7..1c056f7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2002,6 +2002,8 @@ static bool all_unreclaimable(struct zonelist *zonelist,
 
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
 			gfp_zone(sc->gfp_mask), sc->nodemask) {
+		if (zone->all_unreclaimable)
+			continue;
 		if (!populated_zone(zone))
 			continue;
 		if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
-- 
1.7.1