Re: [XEN RFC PATCH 17/40] xen/arm: Introduce DEVICE_TREE_NUMA Kconfig for arm64

[Julien Grall <julien@xxxxxxx>]

Hi,

On 11/08/2021 11:24, Wei Chen wrote:
> We need a Kconfig option to distinguish with ACPI based
> NUMA. So we introduce the new Kconfig option:
> DEVICE_TREE_NUMA in this patch for Arm64.
>
> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> ---
>   xen/arch/arm/Kconfig | 10 ++++++++++
>   1 file changed, 10 insertions(+)
>
> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
> index ecfa6822e4..678cc98ea3 100644
> --- a/xen/arch/arm/Kconfig
> +++ b/xen/arch/arm/Kconfig
> @@ -33,6 +33,16 @@ config ACPI
>           Advanced Configuration and Power Interface (ACPI) support for Xen is
>           an alternative to device tree on ARM64.
>   
> +config DEVICE_TREE_NUMA
The name suggests that NUMA should only be enabled for Device-Tree... 
But the description looks generic.
However, I think the user should only have the choice to say whether 
they want NUMA to be enabled or not. We should not give them the choice 
to enable/disable the parsing for DT/ACPI.
So we should have a generic config that will then select DT (and ACPI in 
the future).
> +       bool "NUMA (Non-Uniform Memory Access) Support (UNSUPPORTED)" if 
> UNSUPPORTED
> +       depends on ARM_64
> +       select NUMA
> +       ---help---
> +
> +         Non-Uniform Memory Access (NUMA) is a computer memory design used in
> +         multiprocessing, where the memory access time depends on the memory
> +         location relative to the processor.
> +
Cheers,

--
Julien Grall