dm zoned: prefer full zones for reclaim

Prefer full zones when selecting the next zone for reclaim.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-zoned-metadata.c

@@ -1941,7 +1941,7 @@ static struct dm_zone *dmz_get_rnd_zone_for_reclaim(struct dmz_metadata *zmd,
 						    unsigned int idx, bool idle)
 {
 	struct dm_zone *dzone = NULL;
-	struct dm_zone *zone;
+	struct dm_zone *zone, *last = NULL;
 	struct list_head *zone_list;
 
 	/* If we have cache zones select from the cache zone list */
@@ -1958,6 +1958,13 @@ static struct dm_zone *dmz_get_rnd_zone_for_reclaim(struct dmz_metadata *zmd,
 			dzone = zone->bzone;
 			if (dzone->dev->dev_idx != idx)
 				continue;
+			if (!last) {
+				last = dzone;
+				continue;
+			}
+			if (last->weight < dzone->weight)
+				continue;
+			dzone = last;
 		} else
 			dzone = zone;
 		if (dmz_lock_zone_reclaim(dzone))