Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754766Ab3HBCIr (ORCPT ); Thu, 1 Aug 2013 22:08:47 -0400 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:62998 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752966Ab3HBCIE (ORCPT ); Thu, 1 Aug 2013 22:08:04 -0400 X-AuditID: 9c93016f-b7b05ae000002bbd-50-51fb1481721a From: Joonsoo Kim To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim , Minchan Kim , Johannes Weiner , Mel Gorman , Rik van Riel , Joonsoo Kim Subject: [PATCH 2/4] mm, migrate: allocation new page lazyily in unmap_and_move() Date: Fri, 2 Aug 2013 11:07:57 +0900 Message-Id: <1375409279-16919-2-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1375409279-16919-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1375409279-16919-1-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 Content-Length: 1562 Lines: 51 We don't need a new page and then go out immediately if some condition is met. Allocation has overhead in comparison with some condition check, so allocating lazyily is preferable solution. Signed-off-by: Joonsoo Kim diff --git a/mm/migrate.c b/mm/migrate.c index 6f0c244..86db87e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -864,10 +864,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, { int rc = 0; int *result = NULL; - struct page *newpage = get_new_page(page, private, &result); - - if (!newpage) - return -ENOMEM; + struct page *newpage = NULL; if (page_count(page) == 1) { /* page was freed from under us. So we are done. */ @@ -878,6 +875,10 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, if (unlikely(split_huge_page(page))) goto out; + newpage = get_new_page(page, private, &result); + if (!newpage) + return -ENOMEM; + rc = __unmap_and_move(page, newpage, force, mode); if (unlikely(rc == MIGRATEPAGE_BALLOON_SUCCESS)) { @@ -908,7 +909,8 @@ out: * Move the new page to the LRU. If migration was not successful * then this will free the page. */ - putback_lru_page(newpage); + if (newpage) + putback_lru_page(newpage); if (result) { if (rc) *result = rc; -- 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/