mm: page_alloc: do not treat a zone that cannot be used for dirty pages as "full"

If a zone cannot be used for a dirty page then it gets marked "full" which
is cached in the zlc and later potentially skipped by allocation requests
that have nothing to do with dirty zones.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8e76624..b4381ea 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1967,7 +1967,7 @@ zonelist_scan:
                 */
                if ((alloc_flags & ALLOC_WMARK_LOW) &&
                    (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
-                       goto this_zone_full;
+                       continue;
 
                mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
                if (!zone_watermark_ok(zone, order, mark,