From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lucas Nussbaum Subject: Re: [PATCH, RFC] jbd2: don't write non-commit blocks synchronously Date: Thu, 6 Mar 2014 19:37:49 +0100 Message-ID: <20140306183749.GA15122@xanadu.blop.info> References: <20140305141343.GA26225@xanadu.blop.info> <20140306135642.GA22136@thunk.org> <20140306172801.GA12751@xanadu.blop.info> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Emmanuel Jeanvoine To: Theodore Ts'o Return-path: Received: from xanadu.blop.info ([178.79.145.134]:36212 "EHLO xanadu.blop.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750829AbaCFSjc (ORCPT ); Thu, 6 Mar 2014 13:39:32 -0500 Content-Disposition: inline In-Reply-To: <20140306172801.GA12751@xanadu.blop.info> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 06/03/14 at 18:28 +0100, Lucas Nussbaum wrote: > On 06/03/14 at 08:56 -0500, Theodore Ts'o wrote: > > On Wed, Mar 05, 2014 at 03:13:43PM +0100, Lucas Nussbaum wrote: > > > TL;DR: we experience long temporary hangs when doing multiple mount -o > > > remount at the same time as other I/O on an ext4 filesystem. > > > > Hi Lukas, > > > > Thanks for this report. Are you willing to try a kernel patch? If > > so, could you try and see if this fixes your issue. From looking at > > your block trace, I saw a large number of suspicious 4k writes from > > the jbd2 layer. > > Hi Ted, > > This patch doesn't solve the problem. It seems that on average, it makes > the situation worse, but I'm not sure if this is just anecdotical > evidence or statistically valid. > > Anything else I could try to gather more information? Two other data points: - same problem with a 2.6.29-2-amd64 kernel from Debian - with that 2.6.29-2-amd64, disabling the journal on the ext4 filesytem using 'tune2fs -O ^has_journal /dev/sda5' makes the problem go away -- | Lucas Nussbaum Assistant professor @ Univ. de Lorraine | | lucas.nussbaum@loria.fr LORIA / AlGorille | | http://www.loria.fr/~lnussbau/ +33 3 54 95 86 19 |