From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 3D8B36B0089 for ; Thu, 9 Dec 2010 10:21:14 -0500 (EST) Received: by yxl31 with SMTP id 31so1481000yxl.14 for ; Thu, 09 Dec 2010 07:21:12 -0800 (PST) Date: Fri, 10 Dec 2010 00:21:02 +0900 From: Minchan Kim Subject: Re: [PATCH 1/6] mm: kswapd: Stop high-order balancing when any suitable zone is balanced Message-ID: <20101209152102.GB1740@barrios-desktop> References: <1291893500-12342-1-git-send-email-mel@csn.ul.ie> <1291893500-12342-2-git-send-email-mel@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1291893500-12342-2-git-send-email-mel@csn.ul.ie> Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Simon Kirby , KOSAKI Motohiro , Shaohua Li , Dave Hansen , Johannes Weiner , Andrew Morton , linux-mm , linux-kernel List-ID: On Thu, Dec 09, 2010 at 11:18:15AM +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: Minchan Kim Looks good to me. -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org