From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2 2/3] mutex: add support for reservation style locks,
 v2
Date: Wed, 10 Apr 2013 09:34:30 +0200
Message-ID: <1365579270.30071.25.camel@laptop>
References: <20130228102452.15191.22673.stgit@patser>
	 <20130228102502.15191.14146.stgit@patser>
	 <1364900432.18374.24.camel@laptop> <515AF1C1.7080508@canonical.com>
	 <1364921954.20640.22.camel@laptop> <1365076908.2609.94.camel@laptop>
	 <20130404133123.GW2228@phenom.ffwll.local>
	 <CAKMK7uG_qLQrZUdE_LRANm7qXPvGUisBx-k=+y=F2gA3=odkrQ@mail.gmail.com>
	 <20130409224223.GD20739@home.goodmis.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Return-path: <linux-arch-owner@vger.kernel.org>
In-Reply-To: <20130409224223.GD20739@home.goodmis.org>
Sender: linux-arch-owner@vger.kernel.org
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, Maarten Lankhorst <maarten.lankhorst@canonical.com>, linux-arch@vger.kernel.org, x86@kernel.org, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, "linaro-mm-sig@lists.linaro.org" <linaro-mm-sig@lists.linaro.org>, rob clark <robclark@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>, "linux-media@vger.kernel.org" <linux-media@vger.kernel.org>
List-Id: dri-devel@lists.freedesktop.org

On Tue, 2013-04-09 at 18:42 -0400, Steven Rostedt wrote:
> What about setting an age as soon as it starts the process
> of grabbing one of these locks? And it keeps the age until it
> successfully grabs and releases all the locks again. It wont reset if
> it
> had to drop the locks and start over.


That is indeed the proposed mechanism. It ensures FIFO fairness between
the various threads that try to acquire a set.