Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935056Ab0GSOlG (ORCPT ); Mon, 19 Jul 2010 10:41:06 -0400 Received: from gir.skynet.ie ([193.1.99.77]:51580 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934486Ab0GSOlD (ORCPT ); Mon, 19 Jul 2010 10:41:03 -0400 Date: Mon, 19 Jul 2010 15:40:47 +0100 From: Mel Gorman To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Johannes Weiner , Wu Fengguang , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Andrew Morton , Andrea Arcangeli Subject: Re: [PATCH 7/8] writeback: sync old inodes first in background writeback Message-ID: <20100719144046.GR13117@csn.ul.ie> References: <1279545090-19169-1-git-send-email-mel@csn.ul.ie> <1279545090-19169-8-git-send-email-mel@csn.ul.ie> <20100719142145.GD12510@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20100719142145.GD12510@infradead.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1571 Lines: 36 On Mon, Jul 19, 2010 at 10:21:45AM -0400, Christoph Hellwig wrote: > On Mon, Jul 19, 2010 at 02:11:29PM +0100, Mel Gorman wrote: > > From: Wu Fengguang > > > > A background flush work may run for ever. So it's reasonable for it to > > mimic the kupdate behavior of syncing old/expired inodes first. > > > > This behavior also makes sense from the perspective of page reclaim. > > File pages are added to the inactive list and promoted if referenced > > after one recycling. If not referenced, it's very easy for pages to be > > cleaned from reclaim context which is inefficient in terms of IO. If > > background flush is cleaning pages, it's best it cleans old pages to > > help minimise IO from reclaim. > > Yes, we absolutely do this. Do you mean we absolutely want to do this? > Wu, do you have an improved version of the > pending or should we put it in this version for now? > Some insight on how the other writeback changes that are being floated around might affect the number of dirty pages reclaim encounters would also be helpful. The tracepoints are there for people to figure it out but any help figuring it out is useful. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/