diff --git a/mm/compaction.c b/mm/compaction.c
index 771775d..0656759 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -431,6 +431,24 @@ static bool suitable_migration_target(struct page *page)
 }
 
 /*
+ * We scan the zone in a circular fashion, starting at
+ * zone->compact_cached_free_pfn. Be careful not to skip if
+ * one compacting thread has just wrapped back to the end of the
+ * zone, but another thread has not.
+ */
+static bool compaction_may_skip(struct zone *zone,
+				struct compact_control *cc)
+{
+	if (!cc->wrapped && zone->compact_cached_free_pfn < cc->start_free_pfn)
+		return true;
+
+	if (cc->wrapped && zone->compact_cached_free_pfn > cc->start_free_pfn)
+		return true;
+
+	return false;
+}
+
+/*
  * Based on information in the current compact_control, find blocks
  * suitable for isolating free pages from and then isolate them.
  */
@@ -471,13 +489,9 @@ static void isolate_freepages(struct zone *zone,
 
 		/*
 		 * Skip ahead if another thread is compacting in the area
-		 * simultaneously. If we wrapped around, we can only skip
-		 * ahead if zone->compact_cached_free_pfn also wrapped to
-		 * above our starting point.
+		 * simultaneously, and has finished with this page block.
 		 */
-		if (cc->order > 0 && (!cc->wrapped ||
-				      zone->compact_cached_free_pfn >
-				      cc->start_free_pfn))
+		if (cc->order > 0 && compaction_may_skip(zone, cc))
 			pfn = min(pfn, zone->compact_cached_free_pfn);
 
 		if (!pfn_valid(pfn))