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 p6VFI0O7220585 for ; Sun, 31 Jul 2011 10:18:00 -0500 Received: from mail-pz0-f43.google.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id B57D952E37D for ; Sun, 31 Jul 2011 08:17:59 -0700 (PDT) Received: from mail-pz0-f43.google.com (mail-pz0-f43.google.com [209.85.210.43]) by cuda.sgi.com with ESMTP id iv9Vakv8FsMu7csz for ; Sun, 31 Jul 2011 08:17:59 -0700 (PDT) Received: by pzk1 with SMTP id 1so7732878pzk.2 for ; Sun, 31 Jul 2011 08:17:58 -0700 (PDT) Date: Mon, 1 Aug 2011 00:17:49 +0900 From: Minchan Kim Subject: Re: [PATCH 6/8] mm: vmscan: Throttle reclaim if encountering too many dirty pages under writeback Message-ID: <20110731151749.GD1735@barrios-desktop> References: <1311265730-5324-1-git-send-email-mgorman@suse.de> <1311265730-5324-7-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1311265730-5324-7-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 , Wu Fengguang , Johannes Weiner On Thu, Jul 21, 2011 at 05:28:48PM +0100, Mel Gorman wrote: > Workloads that are allocating frequently and writing files place a > large number of dirty pages on the LRU. With use-once logic, it is > possible for them to reach the end of the LRU quickly requiring the > reclaimer to scan more to find clean pages. Ordinarily, processes that > are dirtying memory will get throttled by dirty balancing but this > is a global heuristic and does not take into account that LRUs are > maintained on a per-zone basis. This can lead to a situation whereby > reclaim is scanning heavily, skipping over a large number of pages > under writeback and recycling them around the LRU consuming CPU. > > This patch checks how many of the number of pages isolated from the > LRU were dirty. If a percentage of them are dirty, the process will be > throttled if a blocking device is congested or the zone being scanned > is marked congested. The percentage that must be dirty depends on > the priority. At default priority, all of them must be dirty. At > DEF_PRIORITY-1, 50% of them must be dirty, DEF_PRIORITY-2, 25% > etc. i.e. as pressure increases the greater the likelihood the process > will get throttled to allow the flusher threads to make some progress. > > Signed-off-by: Mel Gorman Reviewed-by: Minchan Kim -- Kind regards, Minchan Kim _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs