diff --git a/mm/compaction.c b/mm/compaction.c
index 7077b81a4893710f415bd6d47976beefcff3b6b8..2c1e1ff321bff543b4e1f62b0a6cfddc8e104260 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -943,8 +943,7 @@ static void isolate_freepages(struct compact_control *cc)
 	 * pages on cc->migratepages. We stop searching if the migrate
 	 * and free page scanners meet or enough free pages are isolated.
 	 */
-	for (; block_start_pfn >= low_pfn &&
-			cc->nr_migratepages > cc->nr_freepages;
+	for (; block_start_pfn >= low_pfn;
 				block_end_pfn = block_start_pfn,
 				block_start_pfn -= pageblock_nr_pages,
 				isolate_start_pfn = block_start_pfn) {
@@ -976,6 +975,8 @@ static void isolate_freepages(struct compact_control *cc)
 					block_end_pfn, freelist, false);
 
 		/*
+		 * If we isolated enough freepages, or aborted due to async
+		 * compaction being contended, terminate the loop.
 		 * Remember where the free scanner should restart next time,
 		 * which is where isolate_freepages_block() left off.
 		 * But if it scanned the whole pageblock, isolate_start_pfn
@@ -984,27 +985,31 @@ static void isolate_freepages(struct compact_control *cc)
 		 * In that case we will however want to restart at the start
 		 * of the previous pageblock.
 		 */
-		cc->free_pfn = (isolate_start_pfn < block_end_pfn) ?
-				isolate_start_pfn :
-				block_start_pfn - pageblock_nr_pages;
-
-		/*
-		 * isolate_freepages_block() might have aborted due to async
-		 * compaction being contended
-		 */
-		if (cc->contended)
+		if ((cc->nr_freepages >= cc->nr_migratepages)
+							|| cc->contended) {
+			if (isolate_start_pfn >= block_end_pfn)
+				isolate_start_pfn =
+					block_start_pfn - pageblock_nr_pages;
 			break;
+		} else {
+			/*
+			 * isolate_freepages_block() should not terminate
+			 * prematurely unless contended, or isolated enough
+			 */
+			VM_BUG_ON(isolate_start_pfn < block_end_pfn);
+		}
 	}
 
 	/* split_free_page does not map the pages */
 	map_pages(freelist);
 
 	/*
-	 * If we crossed the migrate scanner, we want to keep it that way
-	 * so that compact_finished() may detect this
+	 * Record where the free scanner will restart next time. Either we
+	 * broke from the loop and set isolate_start_pfn based on the last
+	 * call to isolate_freepages_block(), or we met the migration scanner
+	 * and the loop terminated due to isolate_start_pfn < low_pfn
 	 */
-	if (block_start_pfn < low_pfn)
-		cc->free_pfn = cc->migrate_pfn;
+	cc->free_pfn = isolate_start_pfn;
 }
 
 /*