1 files changed, 48 insertions, 10 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index d9dbb97e607b..f94cbc0b99a5 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -80,6 +80,9 @@ static void reset_isolation_suitable(struct zone *zone)
 	 */
 	if (time_before(jiffies, zone->compact_blockskip_expire))
 		return;
+
+	zone->compact_cached_migrate_pfn = start_pfn;
+	zone->compact_cached_free_pfn = end_pfn;
 	zone->compact_blockskip_expire = jiffies + (HZ * 5);
 
 	/* Walk the zone and mark every pageblock as suitable for isolation */
@@ -103,13 +106,29 @@ static void reset_isolation_suitable(struct zone *zone)
  * If no pages were isolated then mark this pageblock to be skipped in the
  * future. The information is later cleared by reset_isolation_suitable().
  */
-static void update_pageblock_skip(struct page *page, unsigned long nr_isolated)
+static void update_pageblock_skip(struct compact_control *cc,
+			struct page *page, unsigned long nr_isolated,
+			bool migrate_scanner)
 {
+	struct zone *zone = cc->zone;
 	if (!page)
 		return;
 
-	if (!nr_isolated)
+	if (!nr_isolated) {
+		unsigned long pfn = page_to_pfn(page);
 		set_pageblock_skip(page);
+
+		/* Update where compaction should restart */
+		if (migrate_scanner) {
+			if (!cc->finished_update_migrate &&
+			    pfn > zone->compact_cached_migrate_pfn)
+				zone->compact_cached_migrate_pfn = pfn;
+		} else {
+			if (!cc->finished_update_free &&
+			    pfn < zone->compact_cached_free_pfn)
+				zone->compact_cached_free_pfn = pfn;
+		}
+	}
 }
 #else
 static inline bool isolation_suitable(struct compact_control *cc,
@@ -118,7 +137,9 @@ static inline bool isolation_suitable(struct compact_control *cc,
 	return true;
 }
 
-static void update_pageblock_skip(struct page *page, unsigned long nr_isolated)
+static void update_pageblock_skip(struct compact_control *cc,
+			struct page *page, unsigned long nr_isolated,
+			bool migrate_scanner)
 {
 }
 #endif /* CONFIG_COMPACTION */
@@ -327,7 +348,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
 	/* Update the pageblock-skip if the whole pageblock was scanned */
 	if (blockpfn == end_pfn)
-		update_pageblock_skip(valid_page, total_isolated);
+		update_pageblock_skip(cc, valid_page, total_isolated, false);
 
 	return total_isolated;
 }
@@ -533,6 +554,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 		 */
 		if (!cc->sync && last_pageblock_nr != pageblock_nr &&
 		    !migrate_async_suitable(get_pageblock_migratetype(page))) {
+			cc->finished_update_migrate = true;
 			goto next_pageblock;
 		}
 
@@ -583,6 +605,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 		VM_BUG_ON(PageTransCompound(page));
 
 		/* Successfully isolated */
+		cc->finished_update_migrate = true;
 		del_page_from_lru_list(page, lruvec, page_lru(page));
 		list_add(&page->lru, migratelist);
 		cc->nr_migratepages++;
@@ -609,7 +632,7 @@ next_pageblock:
 
 	/* Update the pageblock-skip if the whole pageblock was scanned */
 	if (low_pfn == end_pfn)
-		update_pageblock_skip(valid_page, nr_isolated);
+		update_pageblock_skip(cc, valid_page, nr_isolated, true);
 
 	trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
 
@@ -690,8 +713,10 @@ static void isolate_freepages(struct zone *zone,
 		 * looking for free pages, the search will restart here as
 		 * page migration may have returned some pages to the allocator
 		 */
-		if (isolated)
+		if (isolated) {
+			cc->finished_update_free = true;
 			high_pfn = max(high_pfn, pfn);
+		}
 	}
 
 	/* split_free_page does not map the pages */
@@ -888,6 +913,8 @@ unsigned long compaction_suitable(struct zone *zone, int order)
 static int compact_zone(struct zone *zone, struct compact_control *cc)
 {
 	int ret;
+	unsigned long start_pfn = zone->zone_start_pfn;
+	unsigned long end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 
 	ret = compaction_suitable(zone, cc->order);
 	switch (ret) {
@@ -900,10 +927,21 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 		;
 	}
 
-	/* Setup to move all movable pages to the end of the zone */
-	cc->migrate_pfn = zone->zone_start_pfn;
-	cc->free_pfn = cc->migrate_pfn + zone->spanned_pages;
-	cc->free_pfn &= ~(pageblock_nr_pages-1);
+	/*
+	 * Setup to move all movable pages to the end of the zone. Used cached
+	 * information on where the scanners should start but check that it
+	 * is initialised by ensuring the values are within zone boundaries.
+	 */
+	cc->migrate_pfn = zone->compact_cached_migrate_pfn;
+	cc->free_pfn = zone->compact_cached_free_pfn;
+	if (cc->free_pfn < start_pfn || cc->free_pfn > end_pfn) {
+		cc->free_pfn = end_pfn & ~(pageblock_nr_pages-1);
+		zone->compact_cached_free_pfn = cc->free_pfn;
+	}
+	if (cc->migrate_pfn < start_pfn || cc->migrate_pfn > end_pfn) {
+		cc->migrate_pfn = start_pfn;
+		zone->compact_cached_migrate_pfn = cc->migrate_pfn;
+	}
 
 	/* Clear pageblock skip if there are numerous alloc failures */
 	if (zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT)