From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751451Ab0BISsZ (ORCPT ); Tue, 9 Feb 2010 13:48:25 -0500 Received: from hera.kernel.org ([140.211.167.34]:48455 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751138Ab0BISsX (ORCPT ); Tue, 9 Feb 2010 13:48:23 -0500 Message-ID: <4B71ADB3.5010303@kernel.org> Date: Tue, 09 Feb 2010 10:47:15 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091130 SUSE/3.0.0-1.1.1 Thunderbird/3.0 MIME-Version: 1.0 To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, yinghai@kernel.org, stable@kernel.org, suresh.b.siddha@intel.com, tglx@linutronix.de, shaohui.zheng@intel.com CC: linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/urgent] x86, apic: Don't use logical-flat mode when CPU hotplug may exceed 8 CPUs References: <20100118201256.672679042@sbs-t61.sc.intel.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/09/2010 10:00 AM, tip-bot for Suresh Siddha wrote: > Commit-ID: 418f727639cfc8f03068aae09f473c493c759b9b > Gitweb: http://git.kernel.org/tip/418f727639cfc8f03068aae09f473c493c759b9b > Author: Suresh Siddha > AuthorDate: Tue, 9 Feb 2010 09:18:35 -0800 > Committer: H. Peter Anvin > CommitDate: Tue, 9 Feb 2010 09:29:17 -0800 > > x86, apic: Don't use logical-flat mode when CPU hotplug may exceed 8 CPUs > > We need to fall back from logical-flat APIC mode to physical-flat mode > when we have more than 8 CPUs. However, in the presence of CPU > hotplug, we have to consider the number of possible CPUs rather than > the number of current CPUs; otherwise we may cross the 8-CPU boundary > when CPUs are added later. > > Reported-by: Shaohui Zheng > Acked-by: Shaohui Zheng > Cc: Yinghai Lu > LKML-Reference: <20100118201256.672679042@sbs-t61.sc.intel.com> > Signed-off-by: H. Peter Anvin > Cc: > --- > arch/x86/kernel/apic/apic.c | 2 +- > arch/x86/kernel/apic/probe_64.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index 3987e44..fc1d579 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -1892,7 +1892,7 @@ void __cpuinit generic_processor_info(int apicid, int version) > max_physical_apicid = apicid; > > #ifdef CONFIG_X86_32 > - if (num_processors > 8) { > + if (num_possible_cpus() > 8) { for 32bit you can not use this function yet. that only can be used after prefill_possible_map() > switch (boot_cpu_data.x86_vendor) { > case X86_VENDOR_INTEL: > if (!APIC_XAPIC(version)) { > diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c > index 450fe20..83e9be4 100644 > --- a/arch/x86/kernel/apic/probe_64.c > +++ b/arch/x86/kernel/apic/probe_64.c > @@ -67,7 +67,7 @@ void __init default_setup_apic_routing(void) > } > #endif > > - if (apic == &apic_flat && num_processors > 8) > + if (apic == &apic_flat && num_possible_cpus() > 8) > apic = &apic_physflat; > > printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); please check http://patchwork.kernel.org/patch/74536/ http://patchwork.kernel.org/patch/74533/ http://patchwork.kernel.org/patch/74525/ http://patchwork.kernel.org/patch/74524/ YH