From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755427AbbCFRuj (ORCPT ); Fri, 6 Mar 2015 12:50:39 -0500 Received: from mail-we0-f172.google.com ([74.125.82.172]:33145 "EHLO mail-we0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754109AbbCFRuh (ORCPT ); Fri, 6 Mar 2015 12:50:37 -0500 Message-ID: <1425664233.7562.21.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: Fri, 06 Mar 2015 18:50:33 +0100 In-Reply-To: <54F99F36.4030405@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> 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 Fri, 2015-03-06 at 13:36 +0100, Sebastian Andrzej Siewior wrote: > On 03/06/2015 01:16 PM, Maarten Lankhorst wrote: > > >> Okay so what I the point made here? It is only about the config option, > >> right? What are the preferences here: > >> [ ] yes, the way it is now > > Is my personal preference, but I'm not a locking expert(TM). > > Lets see what Mike says. I currently don't see any reason for people to > switch between both implementations except for testing. And if it > remains hidden then nobody changing code ww_mutex tests against > rt_mutex. That way there is hope :) I don't see much point in an all or nothing config option, it'll just sit idle. If folks can use them where they see fit, they might just do that. We have mutex/rtmutex, so why not ww_mutex/rt_ww_mutex? Looks like a natural extension to me. -Mike