From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752425AbbCIKvL (ORCPT ); Mon, 9 Mar 2015 06:51:11 -0400 Received: from mail-we0-f171.google.com ([74.125.82.171]:36460 "EHLO mail-we0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751559AbbCIKvH (ORCPT ); Mon, 9 Mar 2015 06:51:07 -0400 Message-ID: <1425898264.9329.10.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 11:51:04 +0100 In-Reply-To: <54FD6F5A.1030809@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> 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 11:00 +0100, Sebastian Andrzej Siewior wrote: > 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. 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. -Mike