Hi,
On Fri, Aug 22, 2025 at 03:29:43PM +0000, James Morse wrote:
> MPAM needs to know the size of a cache associated with a particular CPU.
> The DT/ACPI agnostic way of doing this is to ask cacheinfo.
>
> Add a helper to do this.
>
> Signed-off-by: James Morse <james.morse@xxxxxxx>
>
> ---
> Changes since v1:
> * Converted to kdoc.
> * Simplified helper to use get_cpu_cacheinfo_level().
> ---
> include/linux/cacheinfo.h | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
> index 2dcbb69139e9..e12d6f2c6a57 100644
> --- a/include/linux/cacheinfo.h
> +++ b/include/linux/cacheinfo.h
> @@ -148,6 +148,21 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level)
> return ci ? ci->id : -1;
> }
>
> +/**
> + * get_cpu_cacheinfo_size() - Get the size of the cache.
> + * @cpu: The cpu that is associated with the cache.
> + * @level: The level of the cache as seen by @cpu.
> + *
> + * Callers must hold the cpuhp lock.
> + * Returns the cache-size on success, or 0 for an error.
> + */
Nit: Maybe use the wording
cpuhp lock must be held.
in the kerneldoc here, to match the other helpers it sits alongside.
Otherwise, looks reasonable.
> +static inline unsigned int get_cpu_cacheinfo_size(int cpu, int level)
> +{
> + struct cacheinfo *ci = get_cpu_cacheinfo_level(cpu, level);
> +
> + return ci ? ci->size : 0;
> +}
> +
Orphaned function?
Can fs/resctrl/rdtgroup.c:rdtgroup_cbm_to_size() be ported to use this?
If so, this wouldn't just be dead code in this series.
Cheers
---Dave
