Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753490AbZI2XkJ (ORCPT ); Tue, 29 Sep 2009 19:40:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752973AbZI2XkI (ORCPT ); Tue, 29 Sep 2009 19:40:08 -0400 Received: from bld-mail12.adl6.internode.on.net ([150.101.137.97]:48173 "EHLO mail.internode.on.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752830AbZI2XkI (ORCPT ); Tue, 29 Sep 2009 19:40:08 -0400 Date: Wed, 30 Sep 2009 09:39:36 +1000 From: Dave Chinner To: Chris Mason , Wu Fengguang , Andrew Morton , Peter Zijlstra , "Li, Shaohua" , "linux-kernel@vger.kernel.org" , "richard@rsk.demon.co.uk" , "jens.axboe@oracle.com" Subject: Re: regression in page writeback Message-ID: <20090929233936.GG9464@discord.disaster> References: <20090923022622.GB11918@localhost> <20090922193622.42c00012.akpm@linux-foundation.org> <20090923140058.GA2794@think> <20090924031508.GD6456@localhost> <20090925001117.GA9464@discord.disaster> <20090925003820.GK2662@think> <20090925050413.GC9464@discord.disaster> <20090925064503.GA30450@localhost> <20090928010700.GE9464@discord.disaster> <20090928142524.GC6405@think> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090928142524.GC6405@think> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1253 Lines: 30 On Mon, Sep 28, 2009 at 10:25:24AM -0400, Chris Mason wrote: > On Mon, Sep 28, 2009 at 11:07:00AM +1000, Dave Chinner wrote: > > In the context of the setup I was talking about, I meant is that sync > > IO _should_ be unthrottled because it is self-throttling by it's > > very nature. The current code makes no differentiation between the > > two. > > This isn't entirely true anymore. WB_SYNC_ALL is turned into a sync > bio, which is sent down with higher priority. There may be a few spots > that still need to be changed for it, but it is much better than it was. Oh, I didn't realise that had changed - when did WRITE_SYNC_PLUG get introduced? FWIW, I notice that __block_write_full_page(), gfs2, btrfs and jdb use WRITE_SYNC_PLUG to implement this, but it appears that filesystems that have their own writeback code (e.g. XFS) have not been converted (gfs2 and btrfs being the exceptions). Oh well, something else that needs tweaking in XFS... Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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/