From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joonsoo Kim , Vlastimil Babka , Mel Gorman , Rik van Riel , Andrew Morton , Linus Torvalds Subject: [PATCH 3.14 23/37] mm/compaction: do not call suitable_migration_target() on every page Date: Tue, 7 Oct 2014 16:19:40 -0700 Message-Id: <20141007231827.772180887@linuxfoundation.org> In-Reply-To: <20141007231827.043235686@linuxfoundation.org> References: <20141007231827.043235686@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joonsoo Kim 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 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 --- 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))