Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932609AbcJNQ6F (ORCPT ); Fri, 14 Oct 2016 12:58:05 -0400 Received: from foss.arm.com ([217.140.101.70]:40492 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932418AbcJNQ54 (ORCPT ); Fri, 14 Oct 2016 12:57:56 -0400 Date: Fri, 14 Oct 2016 17:58:35 +0100 From: Lorenzo Pieralisi To: Laszlo Ersek Cc: Andrew Jones , Zhen Lei , Will Deacon , Hanjun Guo , main kernel list , linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Shannon Zhao , Wei Huang Subject: Re: aarch64 ACPI boot regressed by commit 7ba5f605f3a0 ("arm64/numa: remove the limitation that cpu0 must bind to node0") Message-ID: <20161014165835.GA24546@red-moon> References: <4a64cd93-5ead-aad6-1057-f42224d65b43@redhat.com> <20161014080524.4hm2b4p373r7rhel@hawk.localdomain> <04f22a79-301b-f05b-033d-c7a24c9f4084@redhat.com> <20161014154231.GA4411@red-moon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 2978 Lines: 84 On Fri, Oct 14, 2016 at 06:22:55PM +0200, Laszlo Ersek wrote: > 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. Sure, will do, I will send it out on Monday. Cheers, Lorenzo