Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932698AbcJNQXP (ORCPT ); Fri, 14 Oct 2016 12:23:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37388 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932618AbcJNQW7 (ORCPT ); Fri, 14 Oct 2016 12:22:59 -0400 Subject: Re: aarch64 ACPI boot regressed by commit 7ba5f605f3a0 ("arm64/numa: remove the limitation that cpu0 must bind to node0") To: Lorenzo Pieralisi References: <4a64cd93-5ead-aad6-1057-f42224d65b43@redhat.com> <20161014080524.4hm2b4p373r7rhel@hawk.localdomain> <04f22a79-301b-f05b-033d-c7a24c9f4084@redhat.com> <20161014154231.GA4411@red-moon> Cc: Andrew Jones , Zhen Lei , Will Deacon , Hanjun Guo , main kernel list , linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Shannon Zhao , Wei Huang From: Laszlo Ersek Message-ID: Date: Fri, 14 Oct 2016 18:22:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161014154231.GA4411@red-moon> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 14 Oct 2016 16:22:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2713 Lines: 77 On 10/14/16 17:42, Lorenzo Pieralisi wrote: > On Fri, Oct 14, 2016 at 05:27:58PM +0200, Laszlo Ersek wrote: >> On 10/14/16 17:01, Laszlo Ersek wrote: >> >>> Maybe the code I >>> tried to analyze in this email was never *meant* to associate CPU#0 with >>> any NUMA node at all (not even node 0); instead, other code -- for >>> example code removed by 7ba5f605f3a0 -- was meant to perform that >>> association. >> >> Staring a bit more at the code, this looks very likely; in acpi_map_gic_cpu_interface() we have >> >>> /* Check if GICC structure of boot CPU is available in the MADT */ >>> if (cpu_logical_map(0) == hwid) { >>> if (bootcpu_valid) { >>> pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n", >>> hwid); >>> return; >>> } >>> bootcpu_valid = true; >>> return; >>> } >> >> which means that this callback function (for parsing the GICC >> structures in the MADT) expects to find the boot processor as well. >> >> Upon finding the boot processor, we set bootcpu_valid to true, and >> that's it -- no association with any NUMA node, and no incrementing of >> "cpu_count". > > Yes, because that's to check the MADT contains the boot cpu hwid. > > Does this help (compile tested only) ? > > -- >8 -- > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index d3f151c..8507703 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -544,6 +544,7 @@ static int __init smp_cpu_setup(int cpu) > return; > } > bootcpu_valid = true; > + early_map_cpu_to_node(0, acpi_numa_get_nid(0, hwid)); > return; > } > > Your patch applies to the tree at v4.8-14604-g29fbff8698fc, but the function the hunk modifies is not smp_cpu_setup(), it is acpi_map_gic_cpu_interface(): > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index d3f151cfd4a1..8507703dabe4 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -544,6 +544,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor) > return; > } > bootcpu_valid = true; > + early_map_cpu_to_node(0, acpi_numa_get_nid(0, hwid)); > return; > } > Anyway, your patch works with both the two-node NUMA configuration Drew suggested for testing, and with the single-node config that I originally used for the bisection. Therefore: Tested-by: Laszlo Ersek Reported-by: Laszlo Ersek Thank you very much for the quick bugfix! And, I think your patch (when you send it for real) should carry Fixes: 7ba5f605f3a0d9495aad539eeb8346d726dfc183 too, because it supplies the cpu#0<->node#xxx association that 7ba5f605f3a0 removed not just for DT, but also for ACPI. Cheers! Laszlo