From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933042AbcJLWhc (ORCPT ); Wed, 12 Oct 2016 18:37:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47874 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932589AbcJLWhY (ORCPT ); Wed, 12 Oct 2016 18:37:24 -0400 Message-ID: <57FEBB22.6090601@redhat.com> Date: Wed, 12 Oct 2016 18:37:22 -0400 From: Prarit Bhargava User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Tim Chen , linux-kernel@vger.kernel.org CC: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Peter Zijlstra , Len Brown , Borislav Petkov , Andi Kleen , Boris Ostrovsky , Jiri Olsa Subject: Re: [PATCH] arch/x86: Remove second call to topology_update_package_map() References: <1476282988-9476-1-git-send-email-prarit@redhat.com> <57FE5171.3030305@redhat.com> <1476301900.4440.6.camel@linux.intel.com> <57FEA313.4060400@redhat.com> <1476310004.4440.16.camel@linux.intel.com> In-Reply-To: <1476310004.4440.16.camel@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 12 Oct 2016 22:37:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/12/2016 06:06 PM, Tim Chen wrote: > On Wed, 2016-10-12 at 16:54 -0400, Prarit Bhargava wrote: >> >> On 10/12/2016 03:51 PM, Tim Chen wrote: >>> >>> On Wed, 2016-10-12 at 11:06 -0400, Prarit Bhargava wrote: >>>> >>>> >>>> On 10/12/2016 10:36 AM, Prarit Bhargava wrote: >>>>> >>>>> >>>>> This was noticed during the investigation of >>>>> >>>>> http://git.kernel.org/tip/2a51fe083eba7f99cbda72f5ef90cdf2f4df882c >>>>> >>>>> A note for reviewers on the cleanup in smp_init_package_map(): The >>>>> per_cpu variable x86_bios_cpu_apicid is initialized to BAD_APICID, and the >>>>> bitmaps are set to false by default so the code isn't necessary. The >>>>> pr_warn() can also be dropped as generic_processor_info() will do a >>>>> pr_warning() in the same situation. >>>>> >>>>> >>>>> >>>>> P. >>>>> >>>>> -----8<----- >>>>> >>>>> After commit 1f12e32f4cd5 ("x86/topology: Create logical package id"), >>>>> topology_update_package_map() is called twice on a CPU. The first call is in >>>>> generic_processor_info(), which is called on all present cpus (found in either >>>>> mptable or ACPI MADT). The second call is in smp_init_package_map() which >>>>> is called later on in the init sequence. >>>>> >>>>> Only a single call is necessary for the kernel to initialize the data >>>>> structures properly. This patch drops the later call in smp_init_package_map() >>>>> and moves smp_init_package_map() out of smp_store_boot_cpu_info(). >>>>> >>>> Self-NAK. >>>> >>>> This seems to not work on systems with an empty socket :/. Looking into this now. >>>> >>>> P. >>> My single node workstation also failed to boot with the patch. >> The patch is incorrect. I'm dropping it completely. >> > > The call from generic_processor_info to topology_update_package_map > during early boot was essentially no op, as physical_package_map has > not have been allocated by smp_init_package_map yet. > > We have to call topology_update_package_map in smp_init_package_map > after allocating physical_package_map to properly set up > physical_package_map. Right -- the patch is incorrect (see above). I'm dropping it completely. P. > > Tim >