From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: RT/ext4/jbd2 circular dependency Date: Thu, 13 Nov 2014 20:06:44 +0100 Message-ID: <20141113190644.GA12075@quack.suse.cz> References: <544940EF.7090907@windriver.com> <544E7144.4080809@windriver.com> <54513BDA.1050804@windriver.com> <20141029231916.GD5000@thunk.org> <20141030232437.GF31927@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Thomas Gleixner , Chris Friesen , Austin Schuh , pavel@pavlinux.ru, "J. Bruce Fields" , linux-ext4@vger.kernel.org, adilger.kernel@dilger.ca, rt-users To: Theodore Ts'o Return-path: Received: from cantor2.suse.de ([195.135.220.15]:45116 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932939AbaKMTGr (ORCPT ); Thu, 13 Nov 2014 14:06:47 -0500 Content-Disposition: inline In-Reply-To: <20141030232437.GF31927@thunk.org> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Thu 30-10-14 19:24:37, Ted Tso wrote: > On Thu, Oct 30, 2014 at 10:11:26PM +0100, Thomas Gleixner wrote: > > > > That's a way better explanation than what I saw in the commit logs and > > it actually maps to the observed traces and stackdumps. > > I can't speak for Jan, but I suspect he didn't realize that there was > a problem. The commit description in b34090e5e2 makes it clear that > the intent was a performance improvement, and not an attempt to fix a > potential deadlock bug. Yeah, correct. When I wrote b34090e5e2 I did that because I have realized that journal reservations would create similar deadlock opportunity as Chris has observed. I hadn't realized the problem is already in the code :) Honza -- Jan Kara SUSE Labs, CR