This is a note to let you know that I've just added the patch titled
mm/compaction: disallow high-order page for migration target
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-disallow-high-order-page-for-migration-target.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 7d348b9ea64db0a315d777ce7d4b06697f946503 Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Date: Mon, 7 Apr 2014 15:37:03 -0700
Subject: mm/compaction: disallow high-order page for migration target
From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
commit 7d348b9ea64db0a315d777ce7d4b06697f946503 upstream.
Purpose of compaction is to get a high order page. Currently, if we
find high-order page while searching migration target page, we break it
to order-0 pages and use them as migration target. It is contrary to
purpose of compaction, so disallow high-order page to be used for
migration target.
Additionally, clean-up logic in suitable_migration_target() to simplify
the code. There is no functional changes from this clean-up.
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 | 15 +++------------
1 file changed, 3 insertions(+), 12 deletions(-)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -217,21 +217,12 @@ static inline bool compact_trylock_irqsa
/* Returns true if the page is within a block suitable for migration to */
static bool suitable_migration_target(struct page *page)
{
- int migratetype = get_pageblock_migratetype(page);
-
- /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
- if (migratetype == MIGRATE_RESERVE)
- return false;
-
- if (is_migrate_isolate(migratetype))
- return false;
-
- /* If the page is a large free page, then allow migration */
+ /* If the page is a large free page, then disallow migration */
if (PageBuddy(page) && page_order(page) >= pageblock_order)
- return true;
+ return false;
/* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
- if (migrate_async_suitable(migratetype))
+ if (migrate_async_suitable(get_pageblock_migratetype(page)))
return true;
/* Otherwise skip the block */
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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