Re: [PATCH v4 08/39] x86/resctrl: Generate default_ctrl instead of sharing it

[Reinette Chatre <reinette.chatre@intel.com>]

Hi James,

On 8/2/24 10:28 AM, James Morse wrote:

> +/**
> + * resctrl_get_default_ctrl() - Return the default control value for this
> + *                              resource.
> + * @r:		The resource whose default control type is queried.
> + */
> +static inline u32 resctrl_get_default_ctrl(struct rdt_resource *r)
> +{
> +	switch (r->schema_fmt) {
> +	case RESCTRL_SCHEMA_BITMAP:
> +		return BIT_MASK(r->cache.cbm_len) - 1;
> +	case RESCTRL_SCHEMA_PERCENTAGE:
> +		return 100u;
> +	case RESCTRL_SCHEMA_MBPS:
> +		return r->membw.max_bw;
> +	}
> +
> +	return WARN_ON_ONCE(1);
> +}
> +

I am concerned where this is headed. Since RESCTRL_SCHEMA_PERCENTAGE remains
in use when resctrl is mounted with mba_MBps the default cannot always
be 100u (it should be MBA_MAX_MBPS when software controller is active).

Reinette