Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270643AbUJUKUD (ORCPT ); Thu, 21 Oct 2004 06:20:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270378AbUJUKSJ (ORCPT ); Thu, 21 Oct 2004 06:18:09 -0400 Received: from mx1.elte.hu ([157.181.1.137]:14997 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S270384AbUJUKRa (ORCPT ); Thu, 21 Oct 2004 06:17:30 -0400 Date: Thu, 21 Oct 2004 12:18:21 +0200 From: Ingo Molnar To: Jens Axboe Cc: Thomas Gleixner , Rui Nuno Capela , LKML , Lee Revell , mark_h_johnson@raytheon.com, "K.R. Foley" , Bill Huey , 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: <20041021101821.GB473@elte.hu> References: <20041016153344.GA16766@elte.hu> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041021101103.GC10531@suse.de> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 30 * 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). yes, that is perfectly true, and sorry if we gave you the wrong impression. the goal of these patches is to do a semaphore->completion conversion in cases where the semaphore was used for completion purposes. It's a bit faster and more readable but not a 'bugfix' in any way. (another set of patches are converting sleep_on() uses to wait_event*() plus waitqueues - those can in fact be considered bugfixes in some cases.) typically the cases where semaphores are held by one task and released by another task happens coincide with this used-for-completion scenario. [ the different-owner assert that triggers in my PREEMPT_REALTIME tree is for completely different reasons and has no impact on upstream at all. (It merely means 'Ingo does some weird stuff again, pester him, not others'.) ] Ingo - 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/