From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id EC38F8E004D for ; Tue, 11 Dec 2018 04:44:38 -0500 (EST) Received: by mail-ed1-f69.google.com with SMTP id e17so6625579edr.7 for ; Tue, 11 Dec 2018 01:44:38 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id w22-v6si708961ejb.132.2018.12.11.01.44.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Dec 2018 01:44:37 -0800 (PST) Date: Tue, 11 Dec 2018 10:44:36 +0100 From: Michal Hocko Subject: Re: [PATCH] mm/alloc: fallback to first node if the wanted node offline Message-ID: <20181211094436.GC1286@dhcp22.suse.cz> References: <20181207075322.GS1286@dhcp22.suse.cz> <20181207113044.GB1286@dhcp22.suse.cz> <20181207142240.GC1286@dhcp22.suse.cz> <20181207155627.GG1286@dhcp22.suse.cz> <20181210123738.GN1286@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Pingfan Liu Cc: Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Mike Rapoport , Bjorn Helgaas , Jonathan Cameron On Tue 11-12-18 16:05:58, Pingfan Liu wrote: > On Mon, Dec 10, 2018 at 8:37 PM Michal Hocko wrote: > > > > On Fri 07-12-18 16:56:27, Michal Hocko wrote: > > > On Fri 07-12-18 22:27:13, Pingfan Liu wrote: > > > [...] > > > > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c > > > > index 1308f54..4dc497d 100644 > > > > --- a/arch/x86/mm/numa.c > > > > +++ b/arch/x86/mm/numa.c > > > > @@ -754,18 +754,23 @@ void __init init_cpu_to_node(void) > > > > { > > > > int cpu; > > > > u16 *cpu_to_apicid = early_per_cpu_ptr(x86_cpu_to_apicid); > > > > + int node, nr; > > > > > > > > BUG_ON(cpu_to_apicid == NULL); > > > > + nr = cpumask_weight(cpu_possible_mask); > > > > + > > > > + /* bring up all possible node, since dev->numa_node */ > > > > + //should check acpi works for node possible, > > > > + for_each_node(node) > > > > + if (!node_online(node)) > > > > + init_memory_less_node(node); > > > > > > I suspect there is no change if you replace for_each_node by > > > for_each_node_mask(nid, node_possible_map) > > > > > > here. If that is the case then we are probably calling > > > free_area_init_node too early. I do not see it yet though. > > > > OK, so it is not about calling it late or soon. It is just that > > node_possible_map is a misnomer and it has a different semantic than > > I've expected. numa_nodemask_from_meminfo simply considers only nodes > > with some memory. So my patch didn't really make any difference and the > > node stayed uninialized. > > > > In other words. Does the following work? I am sorry to wildguess this > > way but I am not able to recreate your setups to play with this myself. > > > No problem. Yeah, in order to debug the patch, you need a numa machine > with a memory-less node. And unlucky, the patch can not work either by > grub bootup or kexec -l boot. There is nothing, just silent. I will > dig into numa_register_memblks() to figure out the problem. I do not have such a machine handy. Anyway, can you post the full serial console log. Maybe I can infer something. It is quite weird that this patch would make an existing situation any worse. -- Michal Hocko SUSE Labs