Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 22/37] mm/compaction: disallow high-order page for migration target | Date | Tue, 7 Oct 2014 16:19:39 -0700 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
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@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> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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 */
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