Patch "mm/compaction: pass only pageblock aligned range to pageblock_pfn_to_page" has been added to the 4.4-stable tree

@@ -553,13 +553,17 @@ unsigned long
 isolate_freepages_range(struct compact_control *cc,
 			unsigned long start_pfn, unsigned long end_pfn)
 {
-	unsigned long isolated, pfn, block_end_pfn;
+	unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
 	LIST_HEAD(freelist);
 
 	pfn = start_pfn;
+	block_start_pfn = pfn & ~(pageblock_nr_pages - 1);
+	if (block_start_pfn < cc->zone->zone_start_pfn)
+		block_start_pfn = cc->zone->zone_start_pfn;
 	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
 
 	for (; pfn < end_pfn; pfn += isolated,
+				block_start_pfn = block_end_pfn,
 				block_end_pfn += pageblock_nr_pages) {
 		/* Protect pfn from changing by isolate_freepages_block */
 		unsigned long isolate_start_pfn = pfn;

@@ -572,11 +576,13 @@ isolate_freepages_range(struct compact_c
 		 * scanning range to right one.
 		 */
 		if (pfn >= block_end_pfn) {
+			block_start_pfn = pfn & ~(pageblock_nr_pages - 1);
 			block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
 			block_end_pfn = min(block_end_pfn, end_pfn);
 		}
 
-		if (!pageblock_pfn_to_page(pfn, block_end_pfn, cc->zone))
+		if (!pageblock_pfn_to_page(block_start_pfn,
+					block_end_pfn, cc->zone))
 			break;
 
 		isolated = isolate_freepages_block(cc, &isolate_start_pfn,

@@ -862,18 +868,23 @@ unsigned long
 isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn,
 							unsigned long end_pfn)
 {
-	unsigned long pfn, block_end_pfn;
+	unsigned long pfn, block_start_pfn, block_end_pfn;
 
 	/* Scan block by block. First and last block may be incomplete */
 	pfn = start_pfn;
+	block_start_pfn = pfn & ~(pageblock_nr_pages - 1);
+	if (block_start_pfn < cc->zone->zone_start_pfn)
+		block_start_pfn = cc->zone->zone_start_pfn;
 	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
 
 	for (; pfn < end_pfn; pfn = block_end_pfn,
+				block_start_pfn = block_end_pfn,
 				block_end_pfn += pageblock_nr_pages) {
 
 		block_end_pfn = min(block_end_pfn, end_pfn);
 
-		if (!pageblock_pfn_to_page(pfn, block_end_pfn, cc->zone))
+		if (!pageblock_pfn_to_page(block_start_pfn,
+					block_end_pfn, cc->zone))
 			continue;
 
 		pfn = isolate_migratepages_block(cc, pfn, block_end_pfn,

@@ -1091,7 +1102,9 @@ int sysctl_compact_unevictable_allowed _
 static isolate_migrate_t isolate_migratepages(struct zone *zone,
 					struct compact_control *cc)
 {
-	unsigned long low_pfn, end_pfn;
+	unsigned long block_start_pfn;
+	unsigned long block_end_pfn;
+	unsigned long low_pfn;
 	unsigned long isolate_start_pfn;
 	struct page *page;
 	const isolate_mode_t isolate_mode =

@@ -1103,16 +1116,21 @@ static isolate_migrate_t isolate_migrate
 	 * initialized by compact_zone()
 	 */
 	low_pfn = cc->migrate_pfn;
+	block_start_pfn = cc->migrate_pfn & ~(pageblock_nr_pages - 1);
+	if (block_start_pfn < zone->zone_start_pfn)
+		block_start_pfn = zone->zone_start_pfn;
 
 	/* Only scan within a pageblock boundary */
-	end_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages);
+	block_end_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages);
 
 	/*
 	 * Iterate over whole pageblocks until we find the first suitable.
 	 * Do not cross the free scanner.
 	 */
-	for (; end_pfn <= cc->free_pfn;
-			low_pfn = end_pfn, end_pfn += pageblock_nr_pages) {
+	for (; block_end_pfn <= cc->free_pfn;
+			low_pfn = block_end_pfn,
+			block_start_pfn = block_end_pfn,
+			block_end_pfn += pageblock_nr_pages) {
 
 		/*
 		 * This can potentially iterate a massively long zone with

@@ -1123,7 +1141,8 @@ static isolate_migrate_t isolate_migrate
 						&& compact_should_abort(cc))
 			break;
 
-		page = pageblock_pfn_to_page(low_pfn, end_pfn, zone);
+		page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn,
+									zone);
 		if (!page)
 			continue;
 

@@ -1142,8 +1161,8 @@ static isolate_migrate_t isolate_migrate
 
 		/* Perform the isolation */
 		isolate_start_pfn = low_pfn;
-		low_pfn = isolate_migratepages_block(cc, low_pfn, end_pfn,
-								isolate_mode);
+		low_pfn = isolate_migratepages_block(cc, low_pfn,
+						block_end_pfn, isolate_mode);
 
 		if (!low_pfn || cc->contended) {
 			acct_isolated(zone, cc);