Re: [PATCH v2 03/29] ACPI / PPTT: Find cache level by cache-id

[Gavin Shan]

On 9/11/25 6:42 AM, James Morse wrote:
> The MPAM table identifies caches by id. The MPAM driver also wants to know
> the cache level to determine if the platform is of the shape that can be
> managed via resctrl. Cacheinfo has this information, but only for CPUs that
> are online.
>
> Waiting for all CPUs to come online is a problem for platforms where
> CPUs are brought online late by user-space.
>
> Add a helper that walks every possible cache, until it finds the one
> identified by cache-id, then return the level.
>
> Signed-off-by: James Morse <james.morse@xxxxxxx>
> ---
> Changes since v1:
>   * Droppeed the cleanup based table freeing, use acpi_get_pptt() instead.
>   * Removed a confusing comment.
>   * Clarified the kernel doc.
>
> Changes since RFC:
>   * acpi_count_levels() now returns a value.
>   * Converted the table-get stuff to use Jonathan's cleanup helper.
>   * Dropped Sudeep's Review tag due to the cleanup change.
> ---
>   drivers/acpi/pptt.c  | 62 ++++++++++++++++++++++++++++++++++++++++++++
>   include/linux/acpi.h |  5 ++++
>   2 files changed, 67 insertions(+)

With existing comments addressed, especially those from Lorenzo Pieralisi:

Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>