From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754680AbbCBMud (ORCPT ); Mon, 2 Mar 2015 07:50:33 -0500 Received: from mail-wi0-f169.google.com ([209.85.212.169]:43632 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753558AbbCBMu3 (ORCPT ); Mon, 2 Mar 2015 07:50:29 -0500 Message-ID: <1425300626.5863.22.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: Maarten Lankhorst Cc: Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar Date: Mon, 02 Mar 2015 13:50:26 +0100 In-Reply-To: <54F4237B.40903@canonical.com> 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> 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, 2015-03-02 at 09:46 +0100, Maarten Lankhorst wrote: > Hey, > > Op 02-03-15 om 04:20 schreef Mike Galbraith: > > On Fri, 2015-02-27 at 17:57 +0100, Sebastian Andrzej Siewior wrote: > >> This patch makes it possible to replace the base mutex by a rt_mutex. In > >> general one would not do this. > > I would argue that the thing should be born as a full fledged primitive, > > not a config option, as an rt_ww_mutex is the ww extension of rt_mutex. > > We have to do the global substitution in -rt, but why should it not > > exist in its own right in mainline? > Well I haven't seen any users that specifically need a rt_ww_mutex, > but flipping the switch on ww_mutex could be useful for testing. :) Imagine a manufacturer of MRI machines.. they have both hard realtime constraints and hefty rendering requirements. I suspect they could find a use for both. -Mike