mm/compaction: do not call suitable_migration_target() on every page

[deliverable/linux.git] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index 9a03fdb1fd848bca383a315f35ff875029c65de8..3a1828541dc0ba4861f0827e1479d4fef5cb31cf 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -244,6 +244,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
        struct page *cursor, *valid_page = NULL;
        unsigned long flags;
        bool locked = false;
+       bool checked_pageblock = false;
 
        cursor = pfn_to_page(blockpfn);
 
@@ -275,8 +276,16 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
                        break;
 
                /* Recheck this is a suitable migration target under lock */
-               if (!strict && !suitable_migration_target(page))
-                       break;
+               if (!strict && !checked_pageblock) {
+                       /*
+                        * We need to check suitability of pageblock only once
+                        * and this isolate_freepages_block() is called with
+                        * pageblock range, so just check once is sufficient.
+                        */
+                       checked_pageblock = true;
+                       if (!suitable_migration_target(page))
+                               break;
+               }
 
                /* Recheck this is a buddy page under lock */
                if (!PageBuddy(page))