1 files changed, 40 insertions, 26 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index d0c7c994e11b..70c0f8cda33f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -89,7 +89,8 @@ static void __reset_isolation_suitable(struct zone *zone)
         unsigned long end_pfn = zone_end_pfn(zone);
         unsigned long pfn;
 
-        zone->compact_cached_migrate_pfn = start_pfn;
+        zone->compact_cached_migrate_pfn[0] = start_pfn;
+        zone->compact_cached_migrate_pfn[1] = start_pfn;
         zone->compact_cached_free_pfn = end_pfn;
         zone->compact_blockskip_flush = false;
 
@@ -131,9 +132,10 @@ void reset_isolation_suitable(pg_data_t *pgdat)
  */
 static void update_pageblock_skip(struct compact_control *cc,
                         struct page *page, unsigned long nr_isolated,
-                        bool migrate_scanner)
+                        bool set_unsuitable, bool migrate_scanner)
 {
         struct zone *zone = cc->zone;
+        unsigned long pfn;
 
         if (cc->ignore_skip_hint)
                 return;
@@ -141,20 +143,31 @@ static void update_pageblock_skip(struct compact_control *cc,
         if (!page)
                 return;
 
-        if (!nr_isolated) {
-                unsigned long pfn = page_to_pfn(page);
+        if (nr_isolated)
+                return;
+
+        /*
+         * Only skip pageblocks when all forms of compaction will be known to
+         * fail in the near future.
+         */
+        if (set_unsuitable)
                 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;
-                }
+        pfn = page_to_pfn(page);
+
+        /* Update where async and sync compaction should restart */
+        if (migrate_scanner) {
+                if (cc->finished_update_migrate)
+                        return;
+                if (pfn > zone->compact_cached_migrate_pfn[0])
+                        zone->compact_cached_migrate_pfn[0] = pfn;
+                if (cc->sync && pfn > zone->compact_cached_migrate_pfn[1])
+                        zone->compact_cached_migrate_pfn[1] = pfn;
+        } else {
+                if (cc->finished_update_free)
+                        return;
+                if (pfn < zone->compact_cached_free_pfn)
+                        zone->compact_cached_free_pfn = pfn;
         }
 }
 #else
@@ -166,7 +179,7 @@ static inline bool isolation_suitable(struct compact_control *cc,
 
 static void update_pageblock_skip(struct compact_control *cc,
                         struct page *page, unsigned long nr_isolated,
-                        bool migrate_scanner)
+                        bool set_unsuitable, bool migrate_scanner)
 {
 }
 #endif /* CONFIG_COMPACTION */
@@ -323,7 +336,8 @@ isolate_fail:
 
         /* Update the pageblock-skip if the whole pageblock was scanned */
         if (blockpfn == end_pfn)
-                update_pageblock_skip(cc, valid_page, total_isolated, false);
+                update_pageblock_skip(cc, valid_page, total_isolated, true,
+                                      false);
 
         count_compact_events(COMPACTFREE_SCANNED, nr_scanned);
         if (total_isolated)
@@ -458,7 +472,7 @@ 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;
+        bool set_unsuitable = true;
         const isolate_mode_t mode = (!cc->sync ? ISOLATE_ASYNC_MIGRATE : 0) |
                                     (unevictable ? ISOLATE_UNEVICTABLE : 0);
 
@@ -535,8 +549,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
                          */
                         mt = get_pageblock_migratetype(page);
                         if (!cc->sync && !migrate_async_suitable(mt)) {
-                                cc->finished_update_migrate = true;
-                                skipped_async_unsuitable = true;
+                                set_unsuitable = false;
                                 goto next_pageblock;
                         }
                 }
@@ -640,11 +653,10 @@ next_pageblock:
         /*
          * 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);
+        if (low_pfn == end_pfn)
+                update_pageblock_skip(cc, valid_page, nr_isolated,
+                                      set_unsuitable, true);
 
         trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
 
@@ -868,7 +880,8 @@ 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_migrate_pfn[0] = zone->zone_start_pfn;
+                zone->compact_cached_migrate_pfn[1] = zone->zone_start_pfn;
                 zone->compact_cached_free_pfn = zone_end_pfn(zone);
 
                 /*
@@ -993,7 +1006,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
          * 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->migrate_pfn = zone->compact_cached_migrate_pfn[cc->sync];
         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);
@@ -1001,7 +1014,8 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
         }
         if (cc->migrate_pfn < start_pfn || cc->migrate_pfn > end_pfn) {
                 cc->migrate_pfn = start_pfn;
-                zone->compact_cached_migrate_pfn = cc->migrate_pfn;
+                zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn;
+                zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;
         }
 
         trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn);