From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754144AbbCIL3S (ORCPT ); Mon, 9 Mar 2015 07:29:18 -0400 Received: from mail-wg0-f54.google.com ([74.125.82.54]:45544 "EHLO mail-wg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752359AbbCIL3P (ORCPT ); Mon, 9 Mar 2015 07:29:15 -0400 Message-ID: <1425900552.6715.7.camel@gmail.com> Subject: Re: [PATCH 2/3] locking: ww_mutex: Allow to use rt_mutex instead of mutex for the baselock From: Mike Galbraith To: Sebastian Andrzej Siewior Cc: Maarten Lankhorst , linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar Date: Mon, 09 Mar 2015 12:29:12 +0100 In-Reply-To: <54FD7EFF.90105@linutronix.de> References: <1425056229-22326-1-git-send-email-bigeasy@linutronix.de> <1425056229-22326-3-git-send-email-bigeasy@linutronix.de> <1425266436.7429.8.camel@gmail.com> <54F4237B.40903@canonical.com> <54F99A38.1070806@linutronix.de> <54F99A9B.1050503@canonical.com> <54F99F36.4030405@linutronix.de> <1425664233.7562.21.camel@gmail.com> <54FD6F5A.1030809@linutronix.de> <1425898264.9329.10.camel@gmail.com> <54FD7EFF.90105@linutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.11 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2015-03-09 at 12:07 +0100, Sebastian Andrzej Siewior wrote: > On 03/09/2015 11:51 AM, Mike Galbraith wrote: > > Why do both mutex and rtmutex then exist one might ask? ;-) No big deal > > either way though, it's not like it becomes immutable once applied. > > You don't choose rtmutex afaik. rtmutex is used by futex (only?) Almost only, but not quite. drivers/media/usb/em28xx/em28xx.h: struct rt_mutex i2c_bus_lock; include/linux/i2c.h: struct rt_mutex bus_lock; kernel/rcu/tree.h: struct rt_mutex boost_mtx;