Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761366AbYFLNaS (ORCPT ); Thu, 12 Jun 2008 09:30:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757802AbYFLNaG (ORCPT ); Thu, 12 Jun 2008 09:30:06 -0400 Received: from gateway-1237.mvista.com ([63.81.120.158]:60995 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757748AbYFLNaE (ORCPT ); Thu, 12 Jun 2008 09:30:04 -0400 Subject: Re: [PATCH 5/5] futex: fix miss ordered wakeups From: Daniel Walker To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, Ulrich Drepper , Arjan van de Ven In-Reply-To: References: <20080611204916.271608740@mvista.com> <20080611204917.523866467@mvista.com> Content-Type: text/plain Date: Thu, 12 Jun 2008 06:30:02 -0700 Message-Id: <1213277402.16459.25.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-5.fc8) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1419 Lines: 37 On Thu, 2008-06-12 at 10:56 +0200, Thomas Gleixner wrote: > On Wed, 11 Jun 2008, Daniel Walker wrote: > > Adds an additional function call to the sched_setscheduler to update the > > waiter position of a task if it happens to be waiting on a futex. This > > ensures that the kernel level waiter ordering is correctly maintained > > based on the changed priority of the task. > > > > I fixed the locking issue noticed by Thomas Gleixner. > > > > This doesn't address userspace at all, only the kernel level wakeups and > > kernel level ordering. > > > > The additional locking added to the futex_wait function has no visible speed > > impact, and only effects waiters which actual enter the kernel. > > The additional locking is just broken and you did not even bother to > test your changes with lockdep. I ran it with lockdep enabled , I didn't get any warnings.. > Aside of this, these patches still add 100 lines of code to achieve > nothing - as dicussed when you previously submitted your changes. > > Please stop wasting everyone's time with that. It achieves correct ordering of the futex waiters inside the kernel, that is in fact _something_ .. Daniel -- 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/