Re: [PATCH v6 18/22] x86/resctrl: Report "Unassigned" for MBM events in ABMC mode

[Reinette Chatre]

Hi Babu,

On 8/6/24 3:00 PM, Babu Moger wrote:
> In ABMC mode, the hardware counter should be assigned to read the MBM
> events.
>
> Report "Unassigned" in case the user attempts to read the events without
> assigning the counter.
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
> v6: Added more explaination in the resctrl.rst
>      Added checks to detect "Unassigned" before reading RMID.
>
> v5: New patch.
> ---
>   Documentation/arch/x86/resctrl.rst        | 11 +++++++++++
>   arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 13 ++++++++++++-
>   2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
> index fe9f10766c4f..aea440ee6107 100644
> --- a/Documentation/arch/x86/resctrl.rst
> +++ b/Documentation/arch/x86/resctrl.rst
> @@ -294,6 +294,17 @@ with the following files:
>   "num_mbm_cntrs":
>   	The number of monitoring counters available for assignment.
>   
> +	Resctrl subsystem provides the interface to count maximum of two
> +	MBM events per group, from a combination of total and local events.
> +	Keeping the current interface, users can assign a maximum of two
> +	monitoring counters per group. User will also have the option to
> +	enable only one counter to the group.
> +
> +	With limited number of counters, system can run out of assignable counters.
> +	In mbm_cntr_assign mode, the MBM event counters will return "Unassigned" if
> +	the counter is not assigned to the event when read. Users need to assign a
> +	counter manually to read the events.

This seems more appropriate for the "mon_data" section.

Reinette