From: Joonsoo Kim Date: Mon, 7 Apr 2014 22:37:03 +0000 (-0700) Subject: mm/compaction: disallow high-order page for migration target X-Git-Tag: upstream/snapshot3+hdmi~1407 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=96b3fde44d498edb0b69f38ee09f3fcc0060d214;hp=1190e5c69c4329c8b8d220e8c149906af1e787c8;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git mm/compaction: disallow high-order page for migration target 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 Acked-by: Vlastimil Babka Cc: Mel Gorman Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/compaction.c b/mm/compaction.c index d5636f9..fcb05da 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -217,21 +217,12 @@ static inline bool compact_trylock_irqsave(spinlock_t *lock, /* 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 */