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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2014-04-07 15:37:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 16:35:51 -0700
commit01ead5340bcf5f3a1cd2452c75516d0ef4d908d7 (patch)
treeeabccdd2c4f1b399ab04e0cc4ed8acff9f2d0281 /mm
parent7d348b9ea64db0a315d777ce7d4b06697f946503 (diff)
downloadlinux-01ead5340bcf5f3a1cd2452c75516d0ef4d908d7.tar.bz2
mm/compaction: do not call suitable_migration_target() on every page
suitable_migration_target() checks that pageblock is suitable for migration target. In isolate_freepages_block(), it is called on every page and this is inefficient. So make it called once per pageblock. suitable_migration_target() also checks if page is highorder or not, but it's criteria for highorder is pageblock order. So calling it once within pageblock range has no problem. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/compaction.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 9a03fdb1fd84..3a1828541dc0 100644
--- 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))