From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756928AbYGFMWH (ORCPT ); Sun, 6 Jul 2008 08:22:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753245AbYGFMV4 (ORCPT ); Sun, 6 Jul 2008 08:21:56 -0400 Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:50510 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752739AbYGFMVz (ORCPT ); Sun, 6 Jul 2008 08:21:55 -0400 Date: Sun, 6 Jul 2008 08:20:58 -0400 From: Theodore Tso To: Arjan van de Ven Cc: akpm@linux-foundation.org, jens.axboe@oracle.com, linux-kernel@vger.kernel.org Subject: Re: PATCH] fix potential latency issues in JBD's journal code Message-ID: <20080706122058.GA26084@mit.edu> Mail-Followup-To: Theodore Tso , Arjan van de Ven , akpm@linux-foundation.org, jens.axboe@oracle.com, linux-kernel@vger.kernel.org References: <20080704192929.2c4dd4ca@infradead.org> <20080706041502.GB21990@mit.edu> <20080705223021.02735dc0@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080705223021.02735dc0@infradead.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-Spam-Flag: NO X-Spam-Score: 0.00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 05, 2008 at 10:30:21PM -0700, Arjan van de Ven wrote: > it's debatable. Because this submit-bh() will sometimes block... it > wouldn't get IO started for that case. I think this is where I'd like > Jens to say what he thinks the rules are; clearly the elevator needs to > treat all of these guys as sync, but maybe the plugging should be .. > flexible. Stupid idea.... maybe the unplugging should be done on the wait side? Has this been considered already? - Ted