From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261349AbVFAJU2 (ORCPT ); Wed, 1 Jun 2005 05:20:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261350AbVFAJU2 (ORCPT ); Wed, 1 Jun 2005 05:20:28 -0400 Received: from mx1.elte.hu ([157.181.1.137]:49614 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S261349AbVFAJUV (ORCPT ); Wed, 1 Jun 2005 05:20:21 -0400 Date: Wed, 1 Jun 2005 11:19:08 +0200 From: Ingo Molnar To: Michal Schmidt Cc: linux-kernel@vger.kernel.org, dwalker@mvista.com, Joe King , ganzinger@mvista.com, Lee Revell , Steven Rostedt Subject: Re: [patch] Real-Time Preemption, -RT-2.6.12-rc4-V0.7.47-06 Message-ID: <20050601091908.GA13041@elte.hu> References: <20050523082637.GA15696@elte.hu> <4294E24E.8000003@stud.feec.vutbr.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4294E24E.8000003@stud.feec.vutbr.cz> User-Agent: Mutt/1.4.2.1i 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 * Michal Schmidt wrote: > Hi Ingo, > > I'm now running -RT-2.6.12-rc4-V0.7.47-08 on amd64. I use cpufreq, but > with the RT kernel it triggers "Kernel BUG at "kernel/latency.c":1295" > (the check for preempt_count underflow). > > I'm attaching a patch which changes a semaphore in cpufreq into a > completion. With this patch, my system runs OK even with cpufreqd. btw., could you please submit this upstream too, so that it doesnt get lost? Semaphore->completion conversions are desirable upstream for cases where the semaphore was in reality not used for mutual exclusion but for completion purposes. (in which case real completions are both more readable and slightly faster) Ingo