From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754125AbbCIKBO (ORCPT ); Mon, 9 Mar 2015 06:01:14 -0400 Received: from www.linutronix.de ([62.245.132.108]:34404 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753619AbbCIKBL (ORCPT ); Mon, 9 Mar 2015 06:01:11 -0400 Message-ID: <54FD6F5A.1030809@linutronix.de> Date: Mon, 09 Mar 2015 11:00:58 +0100 From: Sebastian Andrzej Siewior User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.4.0 MIME-Version: 1.0 To: Mike Galbraith CC: Maarten Lankhorst , linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar Subject: Re: [PATCH 2/3] locking: ww_mutex: Allow to use rt_mutex instead of mutex for the baselock 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> In-Reply-To: <1425664233.7562.21.camel@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/06/2015 06:50 PM, Mike Galbraith wrote: > 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 it could be used for testing. My hope here is that if someone changes something within ww_mutex they test it ob both implementations. > 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. And why would they need it? I would assume that this would only confuse them. And if (for $reason) they need PI they will (most likely) need it for everything not just one lock. > > -Mike > Sebastian