mm: introduce for_each_populated_zone() macro

Impact: cleanup

In almost cases, for_each_zone() is used with populated_zone().  It's
because almost function doesn't need memoryless node information.
Therefore, for_each_populated_zone() can help to make code simplify.

This patch has no functional change.

[akpm@linux-foundation.org: small cleanup]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 3 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1bca60f0c527..301f057fd115 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2061,11 +2061,9 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio,
         struct zone *zone;
         unsigned long ret = 0;
 
-        for_each_zone(zone) {
+        for_each_populated_zone(zone) {
                 enum lru_list l;
 
-                if (!populated_zone(zone))
-                        continue;
                 if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
                         continue;