Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932172Ab0LJBMX (ORCPT ); Thu, 9 Dec 2010 20:12:23 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:45142 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757637Ab0LJBMN (ORCPT ); Thu, 9 Dec 2010 20:12:13 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Fri, 10 Dec 2010 10:06:28 +0900 From: KAMEZAWA Hiroyuki To: Mel Gorman Cc: Simon Kirby , KOSAKI Motohiro , Shaohua Li , Dave Hansen , Johannes Weiner , Andrew Morton , linux-mm , linux-kernel Subject: Re: [PATCH 1/6] mm: kswapd: Stop high-order balancing when any suitable zone is balanced Message-Id: <20101210100628.bd890c77.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1291893500-12342-2-git-send-email-mel@csn.ul.ie> References: <1291893500-12342-1-git-send-email-mel@csn.ul.ie> <1291893500-12342-2-git-send-email-mel@csn.ul.ie> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.0.3 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1233 Lines: 24 On Thu, 9 Dec 2010 11:18:15 +0000 Mel Gorman wrote: > When the allocator enters its slow path, kswapd is woken up to balance the > node. It continues working until all zones within the node are balanced. For > order-0 allocations, this makes perfect sense but for higher orders it can > have unintended side-effects. If the zone sizes are imbalanced, kswapd may > reclaim heavily within a smaller zone discarding an excessive number of > pages. The user-visible behaviour is that kswapd is awake and reclaiming > even though plenty of pages are free from a suitable zone. > > This patch alters the "balance" logic for high-order reclaim allowing kswapd > to stop if any suitable zone becomes balanced to reduce the number of pages > it reclaims from other zones. kswapd still tries to ensure that order-0 > watermarks for all zones are met before sleeping. > > Signed-off-by: Mel Gorman Reviewed-by: KAMEZAWA Hiroyuki -- 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/