Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755847Ab0LIPVO (ORCPT ); Thu, 9 Dec 2010 10:21:14 -0500 Received: from mail-gy0-f174.google.com ([209.85.160.174]:62514 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753044Ab0LIPVM (ORCPT ); Thu, 9 Dec 2010 10:21:12 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=Gb6n4OxTUPFLu/zZUn0ZFzxsbyI/rHdLXQ2ZEtlzIzmO+LnpriFm+/rExLYMbsgI87 qrXdHy4uHBZvJzFCCAPfoZZM/Wbg2qE129TYsLqEYCizQHj0bHUYYfn7uMbQa+1R59rb IMMU2uQ1qHKzT0htgv+NlU8MANTgCd1xHIsac= Date: Fri, 10 Dec 2010 00:21:02 +0900 From: Minchan Kim 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: <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> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1257 Lines: 27 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 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/