Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760284AbZCPRxb (ORCPT ); Mon, 16 Mar 2009 13:53:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757263AbZCPRva (ORCPT ); Mon, 16 Mar 2009 13:51:30 -0400 Received: from gir.skynet.ie ([193.1.99.77]:51205 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756541AbZCPRv1 (ORCPT ); Mon, 16 Mar 2009 13:51:27 -0400 From: Mel Gorman To: Mel Gorman , Linux Memory Management List Cc: Pekka Enberg , Rik van Riel , KOSAKI Motohiro , Christoph Lameter , Johannes Weiner , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra Subject: [PATCH 06/27] Move check for disabled anti-fragmentation out of fastpath Date: Mon, 16 Mar 2009 17:53:20 +0000 Message-Id: <1237226020-14057-7-git-send-email-mel@csn.ul.ie> X-Mailer: git-send-email 1.5.6.5 In-Reply-To: <1237226020-14057-1-git-send-email-mel@csn.ul.ie> References: <1237226020-14057-1-git-send-email-mel@csn.ul.ie> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1794 Lines: 51 On low-memory systems, anti-fragmentation gets disabled as there is nothing it can do and it would just incur overhead shuffling pages between lists constantly. Currently the check is made in the free page fast path for every page. This patch moves it to a slow path. On machines with low memory, there will be small amount of additional overhead as pages get shuffled between lists but it should quickly settle. Signed-off-by: Mel Gorman Reviewed-by: Christoph Lameter --- include/linux/mmzone.h | 3 --- mm/page_alloc.c | 4 ++++ 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 1aca6ce..ca000b8 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -50,9 +50,6 @@ extern int page_group_by_mobility_disabled; static inline int get_pageblock_migratetype(struct page *page) { - if (unlikely(page_group_by_mobility_disabled)) - return MIGRATE_UNMOVABLE; - return get_pageblock_flags_group(page, PB_migrate, PB_migrate_end); } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7ba7705..d815c8f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -171,6 +171,10 @@ int page_group_by_mobility_disabled __read_mostly; static void set_pageblock_migratetype(struct page *page, int migratetype) { + + if (unlikely(page_group_by_mobility_disabled)) + migratetype = MIGRATE_UNMOVABLE; + set_pageblock_flags_group(page, (unsigned long)migratetype, PB_migrate, PB_migrate_end); } -- 1.5.6.5 -- 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/