Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751134AbaBGFIw (ORCPT ); Fri, 7 Feb 2014 00:08:52 -0500 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:57432 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750708AbaBGFIt (ORCPT ); Fri, 7 Feb 2014 00:08:49 -0500 X-AuditID: 9c93016f-b7b0cae0000024a7-39-52f46a5ff6f5 From: Joonsoo Kim To: Andrew Morton Cc: Mel Gorman , Vlastimil Babka , Joonsoo Kim , Rik van Riel , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim Subject: [PATCH 1/5] mm/compaction: disallow high-order page for migration target Date: Fri, 7 Feb 2014 14:08:42 +0900 Message-Id: <1391749726-28910-2-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1391749726-28910-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1391749726-28910-1-git-send-email-iamjoonsoo.kim@lge.com> X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 simply. There is no functional changes from this clean-up. Signed-off-by: Joonsoo Kim diff --git a/mm/compaction.c b/mm/compaction.c index 3a91a2e..bbe1260 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 */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/