Re: [PATCH v5 4/8] x86/resctrl: Add node-scope to the options for feature scope

[Reinette Chatre]

Hi Tony,

On 8/29/2023 4:44 PM, Tony Luck wrote:
> Currently supported resctrl features are all domain scoped the same as the
> scope of the L2 or L3 caches.

fyi ... this patch series seems to use the terms "resctrl feature"
and "resctrl resource" interchangeably and it is not always clear
if the terms mean something different.

> 
> Add "node" as a new option for domain scope.

Could the commit message please get a snippet about what "node"
represents and why this new scope is needed?

> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---
>  include/linux/resctrl.h            | 1 +
>  arch/x86/kernel/cpu/resctrl/core.c | 2 ++
>  2 files changed, 3 insertions(+)
> 
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index 08382548571e..f55cf7afd4eb 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -163,6 +163,7 @@ struct resctrl_schema;
>  enum resctrl_scope {
>  	RESCTRL_L3_CACHE,
>  	RESCTRL_L2_CACHE,
> +	RESCTRL_NODE,
>  };
>  
>  /**
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 3e08aa04a7ff..9fcc264fac6c 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -514,6 +514,8 @@ static int get_domain_id_from_scope(int cpu, enum resctrl_scope scope)
>  		return get_cpu_cacheinfo_id(cpu, 3);
>  	case RESCTRL_L2_CACHE:
>  		return get_cpu_cacheinfo_id(cpu, 2);
> +	case RESCTRL_NODE:
> +		return cpu_to_node(cpu);
>  	default:
>  		WARN_ON_ONCE(1);
>  		break;


Reinette