From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752240AbbIEM1h (ORCPT <rfc822;w@1wt.eu>);
	Sat, 5 Sep 2015 08:27:37 -0400
Received: from smtprelay0237.hostedemail.com ([216.40.44.237]:34597 "EHLO
	smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL)
	by vger.kernel.org with ESMTP id S1750846AbbIEM11 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Sat, 5 Sep 2015 08:27:27 -0400
X-Session-Marker: 726F737465647440676F6F646D69732E6F7267
X-Spam-Summary: 50,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:967:973:988:989:1260:1263:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1539:1593:1594:1711:1714:1730:1747:1777:1792:2194:2199:2393:2525:2553:2560:2563:2682:2685:2859:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3351:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4470:5007:6119:6261:7875:7901:7903:8957:9025:9388:10004:10400:10848:10967:11232:11658:11914:12043:12292:12517:12519:12682:12740:13069:13311:13357:13845:14089:14090:14106:21080,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0
X-HE-Tag: jeans54_6af62a71ac01
X-Filterd-Recvd-Size: 1902
Date: Sat, 5 Sep 2015 08:27:23 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
        linux-rt-users <linux-rt-users@vger.kernel.org>,
        Carsten Emde <C.Emde@osadl.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        John Kacur <jkacur@redhat.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Clark Williams <clark.williams@gmail.com>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC][PATCH RT 0/3] RT: Fix trylock deadlock without msleep()
 hack
Message-ID: <20150905082723.5bc11a25@gandalf.local.home>
In-Reply-To: <20150905081836.2967d80d@gandalf.local.home>
References: <20150904011900.730816481@goodmis.org>
	<alpine.DEB.2.11.1509051217330.15006@nanos>
	<20150905081836.2967d80d@gandalf.local.home>
X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.28; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, 5 Sep 2015 08:18:36 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:


> I even had that solution in my slides at LinuxCon/LinuxPlumbers ;-)

Here's my slides:

http://rostedt.homelinux.com/private/linux-con-rt-into-mainline-2015.pdf

Slide 19 is where I start talking about it.

Slide 21 shows Ingo's solution.

Slide 22 shows the complex issue of dcache.c.

Would your solution work with that code?

-- Steve

> 
> 
> But then I talk about dcache.c. Take a look at that file, and the
> complexity of that. Is it safe to take the inode and dcache parent
> locks after you unlock the other locks?