Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261970AbVDKWTm (ORCPT ); Mon, 11 Apr 2005 18:19:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261961AbVDKWSo (ORCPT ); Mon, 11 Apr 2005 18:18:44 -0400 Received: from smtp.Lynuxworks.com ([207.21.185.24]:21778 "EHLO smtp.lynuxworks.com") by vger.kernel.org with ESMTP id S261964AbVDKWQ7 (ORCPT ); Mon, 11 Apr 2005 18:16:59 -0400 Date: Mon, 11 Apr 2005 15:17:23 -0700 To: Ingo Molnar Cc: "Perez-Gonzalez, Inaky" , Sven-Thorsten Dietrich , Daniel Walker , linux-kernel@vger.kernel.org, Steven Rostedt , Esben Nielsen , Joe Korty Subject: Re: [PATCH] Priority Lists for the RT mutex Message-ID: <20050411221723.GB11685@nietzsche.lynx.com> References: <20050411085737.GA11109@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050411085737.GA11109@elte.hu> User-Agent: Mutt/1.5.8i From: Bill Huey (hui) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1674 Lines: 37 On Mon, Apr 11, 2005 at 10:57:37AM +0200, Ingo Molnar wrote: > > * Perez-Gonzalez, Inaky wrote: > > > Let me re-phrase then: it is a must have only on PI, to make sure you > > don't have a loop when doing it. Maybe is a consequence of the > > algorithm I chose. -However- it should be possible to disable it in > > cases where you are reasonably sure it won't happen (such as kernel > > code). In any case, AFAIR, I still did not implement it. > > are there cases where userspace wants to disable deadlock-detection for > its own locks? I'd disable it for userspace locks. There might be folks that want to implement userspace drivers, but I can't imagine it being 'ok' to have the kernel call out to userspace and have it block correctly. I would expect them to do something else that's less drastic. > the deadlock detector in PREEMPT_RT is pretty much specialized for > debugging (it does all sorts of weird locking tricks to get the first > deadlock out, and to really report it on the console), but it ought to > be possible to make it usable for userspace-controlled locks as well. If I understand things correctly, I'd let that be an RT app issue and the app folks should decided what is appropriate for their setup. If they need a deadlock detector they should decide on their own protocol. The kernel debugging issues are completely different. That's my two cents. bill - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/