[PATCH 2/3] mm/compaction: add and use for_each_populated_zone_pgdat() helper

[Luis Chamberlain]

We can just wrap most of the work done on fragmentation_score_node()
into a pgdat helper for populated zones. Add the helper and use it.

Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
 include/linux/mmzone.h | 8 ++++++++
 mm/compaction.c        | 9 ++-------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a497f189d988..1fd74c7100ec 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1597,6 +1597,14 @@ extern struct zone *next_zone(struct zone *zone);
 			; /* do nothing */		\
 		else
 
+#define for_each_populated_zone_pgdat(zone, pgdat)	\
+	for (zone = pgdat->node_zones;			\
+	     zone;					\
+	     zone = next_zone(zone))			\
+		if (!populated_zone(zone))		\
+			; /* do nothing */		\
+		else
+
 static inline struct zone *zonelist_zone(struct zoneref *zoneref)
 {
 	return zoneref->zone;
diff --git a/mm/compaction.c b/mm/compaction.c
index b961db601df4..023a09d0786d 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2151,16 +2151,11 @@ static unsigned int fragmentation_score_zone_weighted(struct zone *zone)
 static unsigned int fragmentation_score_node(pg_data_t *pgdat)
 {
 	unsigned int score = 0;
+	struct zone *zone;
 	int zoneid;
 
-	for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
-		struct zone *zone;
-
-		zone = &pgdat->node_zones[zoneid];
-		if (!populated_zone(zone))
-			continue;
+	for_each_populated_zone_pgdat(zone, pgdat)
 		score += fragmentation_score_zone_weighted(zone);
-	}
 
 	return score;
 }
-- 
2.43.0