+
+ return groups_scanned;
+}
+
+
+static void shrink_zone(struct zone *zone, struct scan_control *sc)
+{
+ bool do_soft_reclaim = mem_cgroup_should_soft_reclaim(sc);
+ unsigned long nr_scanned = sc->nr_scanned;
+ int scanned_groups;
+
+ scanned_groups = __shrink_zone(zone, sc, do_soft_reclaim);
+ /*
+ * memcg iterator might race with other reclaimer or start from
+ * a incomplete tree walk so the tree walk in __shrink_zone
+ * might have missed groups that are above the soft limit. Try
+ * another loop to catch up with others. Do it just once to
+ * prevent from reclaim latencies when other reclaimers always
+ * preempt this one.
+ */
+ if (do_soft_reclaim && !scanned_groups)
+ __shrink_zone(zone, sc, do_soft_reclaim);
+
+ /*
+ * No group is over the soft limit or those that are do not have
+ * pages in the zone we are reclaiming so we have to reclaim everybody
+ */
+ if (do_soft_reclaim && (sc->nr_scanned == nr_scanned)) {
+ __shrink_zone(zone, sc, false);
+ return;
+ }