Re: [Patch v1] ACPI, x86: fix bug in associating hot-added CPUs withcorresponding NUMA node

[Jiang Liu]

On 2014/2/5 8:14, Rafael J. Wysocki wrote:
> On Monday, January 20, 2014 10:31:54 AM Jiang Liu wrote:
>> Current ACPI cpu hotplug driver fails to associate hot-added CPUs with
>> corresponding NUMA node when doing socket online. The code path to
>> associate CPU with NUMA node is as below:
>> acpi_processor_add()
>>     ->acpi_processor_get_info()
>> 	->acpi_processor_hotadd_init()
>> 	    ->acpi_map_lsapic()
>> 		->_acpi_map_lsapic()
>> 		    ->acpi_map_cpu2node()
>> cpu_subsys_online()
>>     ->try_online_node()
>> 	->node_set_online()
>>
>> When doing socket online, a new NUMA node is introduced in addition to
>> hot-added CPU and memory device. And the new NUMA node is marked as
>> online when onlining hot-added CPUs through sysfs interface
>> /sys/devices/system/cpu/cpuxx/online.
>>
>> On the other hand, acpi_map_cpu2node() will only build the CPU to node
>> map if corresponding NUMA node is already online, so it always fails
>> to associate hot-added CPUs with corresponding NUMA node because the
>> NUMA node is still in offline state.
>>
>> For the fix, we could safely remove the "node_online(node)" check in
>> function acpi_map_cpu2node() because it's only called for hot-added CPUs
>> by acpi_processor_hotadd_init().
>>
>> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> 
> I wonder what the status here is?  Did this patch go anywhere?
Hi Rafael,
	It's still in review stage, hasn't been accepted by any
maintainer yet.
Thanks!
Gerry

> 
>> ---
>>  arch/x86/kernel/acpi/boot.c |    8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
>> index 6c0b43b..7625de9 100644
>> --- a/arch/x86/kernel/acpi/boot.c
>> +++ b/arch/x86/kernel/acpi/boot.c
>> @@ -614,10 +614,10 @@ static void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
>>  	int nid;
>>  
>>  	nid = acpi_get_node(handle);
>> -	if (nid == -1 || !node_online(nid))
>> -		return;
>> -	set_apicid_to_node(physid, nid);
>> -	numa_set_node(cpu, nid);
>> +	if (nid != -1) {
>> +		set_apicid_to_node(physid, nid);
>> +		numa_set_node(cpu, nid);
>> +	}
>>  #endif
>>  }
>>  
>>
> 
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