Re: [PATCH] arm64: Kconfig: Enable NODES_SPAN_OTHER_NODES config for NUMA

[Hoan Tran OS]

Hi Will,

On 6/25/19 3:12 AM, Will Deacon wrote:
> On Mon, Jun 24, 2019 at 02:38:28PM +0000, Hoan Tran OS wrote:
>> Some NUMA nodes have memory ranges that span other nodes.
>> Even though a pfn is valid and between a node's start and end pfns,
>> it may not reside on that node.
>>
>> This patch enables NODES_SPAN_OTHER_NODES config for NUMA to support
>> this type of NUMA layout.
>>
>> Signed-off-by: Hoan Tran <Hoan@xxxxxxxxxxxxxxxxxxxxxx>
>> ---
>>   arch/arm64/Kconfig | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 697ea05..21fc168 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -873,6 +873,13 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
>>   config HOLES_IN_ZONE
>>   	def_bool y
>>   
>> +# Some NUMA nodes have memory ranges that span other nodes.
>> +# Even though a pfn is valid and between a node's start and end pfns,
>> +# it may not reside on that node.
>> +config NODES_SPAN_OTHER_NODES
>> +	def_bool y
>> +	depends on ACPI_NUMA
> 
> How come this is specific to ACPI?

I referred to x86 config. Beside of that, I only can test on the system 
with ACPI supported.

> 
> It would be nice if this was the default, given that only ia64, mips and
> sh appear to be the only NUMA-capable architectures which don't have it.
> In other words, replace the #ifdef CONFIG_NODES_SPAN_OTHER_NODES in
> mm/page_alloc.c with #ifdef CONFIG_NUMA.

Agreed, let me send another patch as your suggestion.

Thanks
Hoan

> Will
>