From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754005Ab1HCLhj (ORCPT ); Wed, 3 Aug 2011 07:37:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57404 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753971Ab1HCLhe (ORCPT ); Wed, 3 Aug 2011 07:37:34 -0400 Date: Wed, 3 Aug 2011 13:37:06 +0200 From: Johannes Weiner To: Mel Gorman Cc: Linux-MM , LKML , XFS , Dave Chinner , Christoph Hellwig , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim Subject: Re: [PATCH 8/8] mm: vmscan: Do not writeback filesystem pages from kswapd Message-ID: <20110803113706.GF27199@redhat.com> References: <1311265730-5324-1-git-send-email-mgorman@suse.de> <1311265730-5324-9-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1311265730-5324-9-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 21, 2011 at 05:28:50PM +0100, Mel Gorman wrote: > Assuming that flusher threads will always write back dirty pages promptly > then it is always faster for reclaimers to wait for flushers. This patch > prevents kswapd writing back any filesystem pages. > > Signed-off-by: Mel Gorman Relying on the flushers may mean that every dirty page in the system has to be written back before the pages from the zone of interest are clean. De-facto we have only one mechanism to stay on top of the dirty pages from a per-zone perspective, and that is single-page writeout from reclaim. While we all agree that this sucks, we can not remove it unless we have a replacement that makes zones reclaimable in a reasonable time frame (or keep them reclaimable in the first place, what per-zone dirty limits attempt to do). As such, please include Nacked-by: Johannes Weiner