The commit is pushed to "branch-rh7-3.10.0-693.11.6.vz7.42.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.11.6.vz7.42.4
------>
commit 4ce80d5f804990b5ee7174f8a40f7ed43cde5c9d
Author: Joonsoo Kim <iamjoonsoo....@lge.com>
Date: Wed Jan 31 18:21:54 2018 +0300
ms/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....@lge.com>
Acked-by: Vlastimil Babka <vba...@suse.cz>
Cc: Mel Gorman <mgor...@suse.de>
Cc: Rik van Riel <r...@redhat.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
(cherry picked from commit 01ead5340bcf5f3a1cd2452c75516d0ef4d908d7)
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
mm/compaction.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 1faade458d38..c29883fe146d 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -247,6 +247,7 @@ 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);
@@ -278,8 +279,16 @@ 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))
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