Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757211AbYHXWvR (ORCPT ); Sun, 24 Aug 2008 18:51:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753524AbYHXWvA (ORCPT ); Sun, 24 Aug 2008 18:51:00 -0400 Received: from atlantis.8hz.com ([212.129.237.78]:54746 "EHLO atlantis.8hz.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753236AbYHXWvA (ORCPT ); Sun, 24 Aug 2008 18:51:00 -0400 Date: Sun, 24 Aug 2008 22:50:58 +0000 From: Sean Young To: Linus Torvalds Cc: "Rafael J. Wysocki" , Ingo Molnar , "H. Peter Anvin" , Alok Kataria , Linux Kernel Mailing List , Adrian Bunk , Andrew Morton , Natalie Protasevich , Kernel Testers List Subject: Re: 2.6.27-rc4-git1: Reported regressions from 2.6.26 Message-ID: <20080824225058.GA55406@atlantis.8hz.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1870 Lines: 53 On Sun, Aug 24, 2008 at 11:52:06AM -0700, Linus Torvalds wrote: > On Sat, 23 Aug 2008, Rafael J. Wysocki wrote: > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=11354 > > Subject : AMD Elan regression with 2.6.27-rc3 > > Submitter : Sean Young > > Date : 2008-08-15 18:37 (9 days old) > > References : http://marc.info/?l=linux-kernel&m=121882578430056&w=4 > > Peter? Ingo? Alok? > > This _looks_ like it might be due to "x86: merge the TSC cpu-freq code" > thing by Alok, where we do this: > > +static struct notifier_block time_cpufreq_notifier_block = { > + .notifier_call = time_cpufreq_notifier > +}; > + > +static int __init cpufreq_tsc(void) > +{ > + cpufreq_register_notifier(&time_cpufreq_notifier_block, > + CPUFREQ_TRANSITION_NOTIFIER); > + return 0; > +} > > but that's just _insane_ if the CPU doesn't even support TSC to begin > with. Also, in the actual time_cpufreq_notifier(), we do: > > if (cpu_has(&cpu_data(freq->cpu), X86_FEATURE_CONSTANT_TSC)) > return 0; > > and this is stupid because: > > (a) if the CPU has no TSC at all, then it sure as hell won't have a > _constant_ one, so we'll actually continue into the function. > > (b) and why the hell is this done at run-time in the notifier, and not in > the "cpufreq_tsc" init function? If anybody mixes totally different > kinds of CPU's in SMP, they deserve whatever they want. > > so why is the patch not something like the appended? > > Sean, does this make any difference for you? Yes, this patch fixes it. Thanks Sean -- 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/