From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752956Ab1GMXhr (ORCPT ); Wed, 13 Jul 2011 19:37:47 -0400 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:24346 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752401Ab1GMXhq (ORCPT ); Wed, 13 Jul 2011 19:37:46 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqYCAJsqHk55LCkBgWdsb2JhbABTp0EVAQEWJiXLQg6GLASjQw Date: Thu, 14 Jul 2011 09:37:43 +1000 From: Dave Chinner To: Mel Gorman Cc: Linux-MM , LKML , XFS , Christoph Hellwig , Johannes Weiner , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim Subject: Re: [PATCH 2/5] mm: vmscan: Do not writeback filesystem pages in kswapd except in high priority Message-ID: <20110713233743.GV23038@dastard> References: <1310567487-15367-1-git-send-email-mgorman@suse.de> <1310567487-15367-3-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1310567487-15367-3-git-send-email-mgorman@suse.de> 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 On Wed, Jul 13, 2011 at 03:31:24PM +0100, Mel Gorman wrote: > It is preferable that no dirty pages are dispatched for cleaning from > the page reclaim path. At normal priorities, this patch prevents kswapd > writing pages. > > However, page reclaim does have a requirement that pages be freed > in a particular zone. If it is failing to make sufficient progress > (reclaiming < SWAP_CLUSTER_MAX at any priority priority), the priority > is raised to scan more pages. A priority of DEF_PRIORITY - 3 is > considered to tbe the point where kswapd is getting into trouble > reclaiming pages. If this priority is reached, kswapd will dispatch > pages for writing. > > Signed-off-by: Mel Gorman Seems reasonable, but btrfs still will ignore this writeback from kswapd, and it doesn't fall over. Given that data point, I'd like to see the results when you stop kswapd from doing writeback altogether as well. Can you try removing it altogether and seeing what that does to your test results? i.e if (page_is_file_cache(page)) { inc_zone_page_state(page, NR_VMSCAN_WRITE_SKIP); goto keep_locked; } Cheers, Dave. -- Dave Chinner david@fromorbit.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p6DNbm1V105340 for ; Wed, 13 Jul 2011 18:37:48 -0500 Received: from ipmail07.adl2.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id DAC836B328 for ; Wed, 13 Jul 2011 16:37:45 -0700 (PDT) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by cuda.sgi.com with ESMTP id HHCU2VgQ04B4bCU9 for ; Wed, 13 Jul 2011 16:37:45 -0700 (PDT) Date: Thu, 14 Jul 2011 09:37:43 +1000 From: Dave Chinner Subject: Re: [PATCH 2/5] mm: vmscan: Do not writeback filesystem pages in kswapd except in high priority Message-ID: <20110713233743.GV23038@dastard> References: <1310567487-15367-1-git-send-email-mgorman@suse.de> <1310567487-15367-3-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1310567487-15367-3-git-send-email-mgorman@suse.de> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Mel Gorman Cc: Rik van Riel , Jan Kara , LKML , XFS , Christoph Hellwig , Linux-MM , Minchan Kim , Wu Fengguang , Johannes Weiner On Wed, Jul 13, 2011 at 03:31:24PM +0100, Mel Gorman wrote: > It is preferable that no dirty pages are dispatched for cleaning from > the page reclaim path. At normal priorities, this patch prevents kswapd > writing pages. > > However, page reclaim does have a requirement that pages be freed > in a particular zone. If it is failing to make sufficient progress > (reclaiming < SWAP_CLUSTER_MAX at any priority priority), the priority > is raised to scan more pages. A priority of DEF_PRIORITY - 3 is > considered to tbe the point where kswapd is getting into trouble > reclaiming pages. If this priority is reached, kswapd will dispatch > pages for writing. > > Signed-off-by: Mel Gorman Seems reasonable, but btrfs still will ignore this writeback from kswapd, and it doesn't fall over. Given that data point, I'd like to see the results when you stop kswapd from doing writeback altogether as well. Can you try removing it altogether and seeing what that does to your test results? i.e if (page_is_file_cache(page)) { inc_zone_page_state(page, NR_VMSCAN_WRITE_SKIP); goto keep_locked; } Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id 51B3C6B004A for ; Wed, 13 Jul 2011 19:37:47 -0400 (EDT) Date: Thu, 14 Jul 2011 09:37:43 +1000 From: Dave Chinner Subject: Re: [PATCH 2/5] mm: vmscan: Do not writeback filesystem pages in kswapd except in high priority Message-ID: <20110713233743.GV23038@dastard> References: <1310567487-15367-1-git-send-email-mgorman@suse.de> <1310567487-15367-3-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1310567487-15367-3-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Linux-MM , LKML , XFS , Christoph Hellwig , Johannes Weiner , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim On Wed, Jul 13, 2011 at 03:31:24PM +0100, Mel Gorman wrote: > It is preferable that no dirty pages are dispatched for cleaning from > the page reclaim path. At normal priorities, this patch prevents kswapd > writing pages. > > However, page reclaim does have a requirement that pages be freed > in a particular zone. If it is failing to make sufficient progress > (reclaiming < SWAP_CLUSTER_MAX at any priority priority), the priority > is raised to scan more pages. A priority of DEF_PRIORITY - 3 is > considered to tbe the point where kswapd is getting into trouble > reclaiming pages. If this priority is reached, kswapd will dispatch > pages for writing. > > Signed-off-by: Mel Gorman Seems reasonable, but btrfs still will ignore this writeback from kswapd, and it doesn't fall over. Given that data point, I'd like to see the results when you stop kswapd from doing writeback altogether as well. Can you try removing it altogether and seeing what that does to your test results? i.e if (page_is_file_cache(page)) { inc_zone_page_state(page, NR_VMSCAN_WRITE_SKIP); goto keep_locked; } Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org