Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268168AbUJNXta (ORCPT ); Thu, 14 Oct 2004 19:49:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268100AbUJNXsv (ORCPT ); Thu, 14 Oct 2004 19:48:51 -0400 Received: from mx2.elte.hu ([157.181.151.9]:54229 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S267916AbUJNXqM (ORCPT ); Thu, 14 Oct 2004 19:46:12 -0400 Date: Fri, 15 Oct 2004 01:46:03 +0200 From: Ingo Molnar To: Karim Yaghmour Cc: linux-kernel@vger.kernel.org, Thomas Zanussi , Robert Wisniewski , Richard J Moore , Michel Dagenais Subject: Re: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U0 Message-ID: <20041014234603.GA22964@elte.hu> References: <20041011215909.GA20686@elte.hu> <20041012091501.GA18562@elte.hu> <20041012123318.GA2102@elte.hu> <20041012195424.GA3961@elte.hu> <20041013061518.GA1083@elte.hu> <20041014002433.GA19399@elte.hu> <416F0071.3040304@opersys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <416F0071.3040304@opersys.com> 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: 1014 Lines: 27 * Karim Yaghmour wrote: > > Ingo Molnar wrote: > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.9-rc4-mm1-U0 > > I notice: > + local_irq_save(flags); > + ____trace(&__get_cpu_var(trace), eip, parent_eip); > + local_irq_restore(flags); > > Why not use the lockless logging available in relayfs, you'll avoid > the interrupt disabling altogether since, umm ... it's lockless. i just added something ad-hoc. I wanted it to be accurate across interrupt entries. I have not looked at the relayfs locking but how does it solve that? Also, cli/sti makes it obviously SMP-safe and is pretty cheap on all x86 CPUs. (Also, i didnt want to use preempt_disable/enable because the tracer interacts with that code quite heavily.) 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/