From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754956Ab1GNPKE (ORCPT ); Thu, 14 Jul 2011 11:10:04 -0400 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:44790 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754543Ab1GNPKB (ORCPT ); Thu, 14 Jul 2011 11:10:01 -0400 Date: Thu, 14 Jul 2011 11:09:59 -0400 From: Christoph Hellwig To: Mel Gorman Cc: Linux-MM , LKML , XFS , Dave Chinner , Christoph Hellwig , Johannes Weiner , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim Subject: Re: [PATCH 5/5] mm: writeback: Prioritise dirty inodes encountered by direct reclaim for background flushing Message-ID: <20110714150959.GA30936@infradead.org> References: <1310567487-15367-1-git-send-email-mgorman@suse.de> <1310567487-15367-6-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1310567487-15367-6-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 13, 2011 at 03:31:27PM +0100, Mel Gorman wrote: > It is preferable that no dirty pages are dispatched from the page > reclaim path. If reclaim is encountering dirty pages, it implies that > either reclaim is getting ahead of writeback or use-once logic has > prioritise pages for reclaiming that are young relative to when the > inode was dirtied. what does this buy us? If at all we should prioritize by a zone, e.g. tell write_cache_pages only to bother with writing things out if the dirty page is in a given zone. We'd probably still cluster around it to make sure we get good I/O patterns, but would only start I/O if it has a page we actually care about.