Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S935247AbaGXX0W (ORCPT <rfc822;w@1wt.eu>);
	Thu, 24 Jul 2014 19:26:22 -0400
Received: from e32.co.us.ibm.com ([32.97.110.150]:59697 "EHLO
	e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S934651AbaGXX0T (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 24 Jul 2014 19:26:19 -0400
Date: Thu, 24 Jul 2014 16:26:05 -0700
From: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
To: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>,
        David Rientjes <rientjes@google.com>,
        Mike Galbraith <umgwanakikbuti@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        Toshi Kani <toshi.kani@hp.com>, Igor Mammedov <imammedo@redhat.com>,
        Borislav Petkov <bp@alien8.de>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Tang Chen <tangchen@cn.fujitsu.com>,
        Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
        Lans Zhang <jia.zhang@windriver.com>, Tony Luck <tony.luck@intel.com>,
        linux-mm@kvack.org, linux-hotplug@vger.kernel.org,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        linux-pm@vger.kernel.org
Subject: Re: [RFC Patch V1 29/30] mm, x86: Enable memoryless node support to
 better support CPU/memory hotplug
Message-ID: <20140724232605.GB24458@linux.vnet.ibm.com>
References: <1405064267-11678-1-git-send-email-jiang.liu@linux.intel.com>
 <1405064267-11678-30-git-send-email-jiang.liu@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1405064267-11678-30-git-send-email-jiang.liu@linux.intel.com>
X-Operating-System: Linux 3.13.0-32-generic (x86_64)
User-Agent: Mutt/1.5.21 (2010-09-15)
X-TM-AS-MML: disable
X-Content-Scanned: Fidelis XPS MAILER
x-cbid: 14072423-0928-0000-0000-000003A6139E
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 11.07.2014 [15:37:46 +0800], Jiang Liu wrote:
> With current implementation, all CPUs within a NUMA node will be
> assocaited with another NUMA node if the node has no memory installed.

<snip>

> ---
>  arch/x86/Kconfig            |    3 +++
>  arch/x86/kernel/acpi/boot.c |    5 ++++-
>  arch/x86/kernel/smpboot.c   |    2 ++
>  arch/x86/mm/numa.c          |   42 +++++++++++++++++++++++++++++++++++-------
>  4 files changed, 44 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index a8f749ef0fdc..f35b25b88625 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1887,6 +1887,9 @@ config USE_PERCPU_NUMA_NODE_ID
>  	def_bool y
>  	depends on NUMA
> 
> +config HAVE_MEMORYLESS_NODES
> +	def_bool NUMA
> +
>  config ARCH_ENABLE_SPLIT_PMD_PTLOCK
>  	def_bool y
>  	depends on X86_64 || X86_PAE
> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
> index 86281ffb96d6..3b5641703a49 100644
> --- a/arch/x86/kernel/acpi/boot.c
> +++ b/arch/x86/kernel/acpi/boot.c
> @@ -612,6 +612,8 @@ static void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
>  	if (nid != -1) {
>  		set_apicid_to_node(physid, nid);
>  		numa_set_node(cpu, nid);
> +		if (node_online(nid))
> +			set_cpu_numa_mem(cpu, local_memory_node(nid));

How common is it for this method to be called for a CPU on an offline
node? Aren't you fixing this in the next patch (so maybe the order
should be changed?)?

>  	}
>  #endif
>  }
> @@ -644,9 +646,10 @@ int acpi_unmap_lsapic(int cpu)
>  {
>  #ifdef CONFIG_ACPI_NUMA
>  	set_apicid_to_node(per_cpu(x86_cpu_to_apicid, cpu), NUMA_NO_NODE);
> +	set_cpu_numa_mem(cpu, NUMA_NO_NODE);
>  #endif
> 
> -	per_cpu(x86_cpu_to_apicid, cpu) = -1;
> +	per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;

I think this is an unrelated change?

>  	set_cpu_present(cpu, false);
>  	num_processors--;
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 5492798930ef..4a5437989ffe 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -162,6 +162,8 @@ static void smp_callin(void)
>  		      __func__, cpuid);
>  	}
> 
> +	set_numa_mem(local_memory_node(cpu_to_node(cpuid)));
> +

Note that you might hit the same issue I reported on powerpc, if
smp_callin() is part of smp_init(). The waitqueue initialization code
depends on cpu_to_node() [and eventually cpu_to_mem()] to be initialized
quite early.

Thanks,
Nish

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/