From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759367Ab1JFWep (ORCPT ); Thu, 6 Oct 2011 18:34:45 -0400 Received: from s15228384.onlinehome-server.info ([87.106.30.177]:38030 "EHLO mail.x86-64.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751501Ab1JFWeo (ORCPT ); Thu, 6 Oct 2011 18:34:44 -0400 Date: Fri, 7 Oct 2011 00:34:38 +0200 From: Borislav Petkov To: Tejun Heo Cc: "Srivatsa S. Bhat" , Borislav Petkov , "Rafael J. Wysocki" , Borislav Petkov , "tigran@aivazian.fsnet.co.uk" , "tglx@linutronix.de" , "mingo@elte.hu" , "hpa@zytor.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , Linux PM mailing list Subject: Re: [BUGFIX][PATCH RESEND] Freezer, CPU hotplug, x86 Microcode: Fix task freezing failures Message-ID: <20111006223438.GA27702@aftab> References: <20111002195023.GC31799@mtj.dyndns.org> <201110052226.58373.rjw@sisk.pl> <4E8CC8FA.2090100@linux.vnet.ibm.com> <201110060043.19583.rjw@sisk.pl> <4E8D4FC6.1080204@linux.vnet.ibm.com> <20111006083439.GA21575@aftab> <4E8DCDA6.8030802@linux.vnet.ibm.com> <4E8E1125.4050701@linux.vnet.ibm.com> <20111006221334.GB7085@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111006221334.GB7085@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 06, 2011 at 06:13:34PM -0400, Tejun Heo wrote: > Hello, > > On Fri, Oct 07, 2011 at 02:05:49AM +0530, Srivatsa S. Bhat wrote: > ... > > diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c > > index f924280..cd7ef2f 100644 > > --- a/arch/x86/kernel/microcode_core.c > > +++ b/arch/x86/kernel/microcode_core.c > > @@ -483,7 +483,15 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu) > > sysfs_remove_group(&sys_dev->kobj, &mc_attr_group); > > pr_debug("CPU%d removed\n", cpu); > > break; > > - case CPU_DEAD: > > + > > + /* > > + * Do not invalidate the microcode if a CPU goes offline, > > + * because it would be impossible to get the microcode again > > + * from userspace when the CPU comes back up, if the userspace > > + * happens to be frozen at that moment by the freezer subsystem, > > + * for example, due to a suspend operation in progress. > > + */ > > + > > This still looks like a bandaid to me. The exclusion approach didn't > pan out? Well, this saves us the needless reloading of the ucode image when the CPU comes back online and is an annoyance fix and onlining path speedup in its own right. I, as you, thought that the exclusion approach should be the proper fix. Srivatsa? Thanks. -- Regards/Gruss, Boris. Advanced Micro Devices GmbH Einsteinring 24, 85609 Dornach GM: Alberto Bozzo Reg: Dornach, Landkreis Muenchen HRB Nr. 43632 WEEE Registernr: 129 19551