Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270829AbUJUU0i (ORCPT ); Thu, 21 Oct 2004 16:26:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270910AbUJUUVt (ORCPT ); Thu, 21 Oct 2004 16:21:49 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:26076 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S270928AbUJUUSy (ORCPT ); Thu, 21 Oct 2004 16:18:54 -0400 Date: Thu, 21 Oct 2004 22:14:43 +0200 From: Jens Axboe To: Bill Huey Cc: Thomas Gleixner , Rui Nuno Capela , Ingo Molnar , LKML , Lee Revell , mark_h_johnson@raytheon.com, "K.R. Foley" , Adam Heath , Florian Schmidt , Michal Schmidt , Fernando Pablo Lopez-Lezcano Subject: Re: [patch] Real-Time Preemption, -RT-2.6.9-rc4-mm1-U8 Message-ID: <20041021201443.GF32465@suse.de> References: <20041018145008.GA25707@elte.hu> <20041019124605.GA28896@elte.hu> <20041019180059.GA23113@elte.hu> <20041020094508.GA29080@elte.hu> <30690.195.245.190.93.1098349976.squirrel@195.245.190.93> <1098350190.26758.24.camel@thomas> <20041021095344.GA10531@suse.de> <1098352441.26758.30.camel@thomas> <20041021101103.GC10531@suse.de> <20041021195842.GA23864@nietzsche.lynx.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041021195842.GA23864@nietzsche.lynx.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1253 Lines: 27 On Thu, Oct 21 2004, Bill Huey wrote: > On Thu, Oct 21, 2004 at 12:11:03PM +0200, Jens Axboe wrote: > > I didn't look at the USB code, I'm just saying that it's perfectly valid > > use of a semaphore the pattern you describe (process A holding it, > > process B releasing it). > > A lot of things are perfectly "valid" in the Linux kernel regarding > stuff like that are a bit irregular. But the preemption work about > to stress these things in ways that was never designed to which is > why these patches are needed. Having a clear use of various locking > conventions is key to getting this system to behave in a predictable > manner. Quite simply, Linux was never targetted to do this and the > sloppiness is showing so it's got to be removed. I have to disagree, I don't think the above use is either convoluted or sloppy in any way. Now that we have the completion structure, certain things are surely better implemented as such. But the old use is perfectly valid and logical, imho. -- Jens Axboe - 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/