diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6298a40902fc..dbf1a1faa40d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2100,6 +2100,14 @@ static bool can_steal_fallback(unsigned int order, int start_mt)
 	if (order >= pageblock_order)
 		return true;
 
+	/*
+	 * Movable pages won't cause permanent fragmentation, so when you alloc
+	 * small pages, you just need to temporarily steal unmovable or
+	 * reclaimable pages that are closest to the request size.  After a
+	 * while, memory compaction may occur to form large contiguous pages,
+	 * and the next movable allocation may not need to steal.  Unmovable and
+	 * reclaimable allocations need to actually steal pages.
+	 */
 	if (order >= pageblock_order / 2 ||
 		start_mt == MIGRATE_RECLAIMABLE ||
 		start_mt == MIGRATE_UNMOVABLE ||