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

[Jiang Liu]

Ping...

On 2014/2/7 20:03, Rafael J. Wysocki wrote:
> On Friday, February 07, 2014 05:17:45 PM Jiang Liu wrote:
>>
>> 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.
> 
> OK
> 
> Peter, are you fine with the patch below?
> 
> Rafael
> 
> 
>>>
>>>> ---
>>>>  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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