This is a note to let you know that I've just added the patch titled
mm/compaction: do not call suitable_migration_target() on every page
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-compaction-do-not-call-suitable_migration_target-on-every-page.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 01ead5340bcf5f3a1cd2452c75516d0ef4d908d7 Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Date: Mon, 7 Apr 2014 15:37:04 -0700
Subject: mm/compaction: do not call suitable_migration_target() on every page
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
commit 01ead5340bcf5f3a1cd2452c75516d0ef4d908d7 upstream.
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@xxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -244,6 +244,7 @@ static unsigned long isolate_freepages_b
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_b
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))
Patches currently in stable-queue which might be from iamjoonsoo.kim@xxxxxxx are
queue-3.14/mm-compaction-do-not-call-suitable_migration_target-on-every-page.patch
queue-3.14/mm-compaction-avoid-isolating-pinned-pages.patch
queue-3.14/mm-compaction-disallow-high-order-page-for-migration-target.patch
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