X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=mm%2Fcompaction.c;h=3a91a2ea3d343d5bb22fdc1a5e67660a133de5e0;hb=7e21774db5cc9cf8fe93a64a2f0c6cf47db8ab24;hp=f58bcd016f432dd094d6f6378aa53f9799d30811;hpb=7cfa7b547337faf5890c8c5f091e081fb79caf73;p=firefly-linux-kernel-4.4.55.git

diff --git a/mm/compaction.c b/mm/compaction.c
index f58bcd016f43..3a91a2ea3d34 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -459,6 +459,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 	unsigned long flags;
 	bool locked = false;
 	struct page *page = NULL, *valid_page = NULL;
+	bool skipped_async_unsuitable = false;
 
 	/*
 	 * Ensure that there are not too many pages isolated from the LRU
@@ -534,6 +535,7 @@ 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;
+			skipped_async_unsuitable = true;
 			goto next_pageblock;
 		}
 
@@ -627,8 +629,13 @@ next_pageblock:
 	if (locked)
 		spin_unlock_irqrestore(&zone->lru_lock, flags);
 
-	/* Update the pageblock-skip if the whole pageblock was scanned */
-	if (low_pfn == end_pfn)
+	/*
+	 * Update the pageblock-skip information and cached scanner pfn,
+	 * if the whole pageblock was scanned without isolating any page.
+	 * This is not done when pageblock was skipped due to being unsuitable
+	 * for async compaction, so that eventual sync compaction can try.
+	 */
+	if (low_pfn == end_pfn && !skipped_async_unsuitable)
 		update_pageblock_skip(cc, valid_page, nr_isolated, true);
 
 	trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
@@ -660,7 +667,7 @@ static void isolate_freepages(struct zone *zone,
 	 * is the end of the pageblock the migration scanner is using.
 	 */
 	pfn = cc->free_pfn;
-	low_pfn = cc->migrate_pfn + pageblock_nr_pages;
+	low_pfn = ALIGN(cc->migrate_pfn + 1, pageblock_nr_pages);
 
 	/*
 	 * Take care that if the migration scanner is at the end of the zone
@@ -676,7 +683,7 @@ static void isolate_freepages(struct zone *zone,
 	 * pages on cc->migratepages. We stop searching if the migrate
 	 * and free page scanners meet or enough free pages are isolated.
 	 */
-	for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
+	for (; pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
 					pfn -= pageblock_nr_pages) {
 		unsigned long isolated;
 
@@ -738,7 +745,14 @@ static void isolate_freepages(struct zone *zone,
 	/* split_free_page does not map the pages */
 	map_pages(freelist);
 
-	cc->free_pfn = high_pfn;
+	/*
+	 * If we crossed the migrate scanner, we want to keep it that way
+	 * so that compact_finished() may detect this
+	 */
+	if (pfn < low_pfn)
+		cc->free_pfn = max(pfn, zone->zone_start_pfn);
+	else
+		cc->free_pfn = high_pfn;
 	cc->nr_freepages = nr_freepages;
 }
 
@@ -837,6 +851,10 @@ static int compact_finished(struct zone *zone,
 
 	/* Compaction run completes if the migrate and free scanner meet */
 	if (cc->free_pfn <= cc->migrate_pfn) {
+		/* Let the next compaction start anew. */
+		zone->compact_cached_migrate_pfn = zone->zone_start_pfn;
+		zone->compact_cached_free_pfn = zone_end_pfn(zone);
+
 		/*
 		 * Mark that the PG_migrate_skip information should be cleared
 		 * by kswapd when it goes to sleep. kswapd does not set the
@@ -946,6 +964,14 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 		;
 	}
 
+	/*
+	 * Clear pageblock skip if there were failures recently and compaction
+	 * is about to be retried after being deferred. kswapd does not do
+	 * this reset as it'll reset the cached information when going to sleep.
+	 */
+	if (compaction_restarting(zone, cc->order) && !current_is_kswapd())
+		__reset_isolation_suitable(zone);
+
 	/*
 	 * 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
@@ -962,13 +988,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 		zone->compact_cached_migrate_pfn = cc->migrate_pfn;
 	}
 
-	/*
-	 * Clear pageblock skip if there were failures recently and compaction
-	 * is about to be retried after being deferred. kswapd does not do
-	 * this reset as it'll reset the cached information when going to sleep.
-	 */
-	if (compaction_restarting(zone, cc->order) && !current_is_kswapd())
-		__reset_isolation_suitable(zone);
+	trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn);
 
 	migrate_prep_local();
 
@@ -1003,7 +1023,11 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 		if (err) {
 			putback_movable_pages(&cc->migratepages);
 			cc->nr_migratepages = 0;
-			if (err == -ENOMEM) {
+			/*
+			 * migrate_pages() may return -ENOMEM when scanners meet
+			 * and we want compact_finished() to detect it
+			 */
+			if (err == -ENOMEM && cc->free_pfn > cc->migrate_pfn) {
 				ret = COMPACT_PARTIAL;
 				goto out;
 			}
@@ -1015,6 +1039,8 @@ out:
 	cc->nr_freepages -= release_freepages(&cc->freepages);
 	VM_BUG_ON(cc->nr_freepages != 0);
 
+	trace_mm_compaction_end(ret);
+
 	return ret;
 }
 
@@ -1120,12 +1146,11 @@ static void __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
 			compact_zone(zone, cc);
 
 		if (cc->order > 0) {
-			int ok = zone_watermark_ok(zone, cc->order,
-						low_wmark_pages(zone), 0, 0);
-			if (ok && cc->order >= zone->compact_order_failed)
-				zone->compact_order_failed = cc->order + 1;
+			if (zone_watermark_ok(zone, cc->order,
+						low_wmark_pages(zone), 0, 0))
+				compaction_defer_reset(zone, cc->order, false);
 			/* Currently async compaction is never deferred. */
-			else if (!ok && cc->sync)
+			else if (cc->sync)
 				defer_compaction(zone, cc->order);
 		}