Re: [RFC] mpam,x86,fs/resctrl: Generic schema description Proof of Concept

From: Reinette Chatre

Date: Wed Jun 10 2026 - 11:23:34 EST


Hi Drew,

On 6/9/26 9:31 PM, Drew Fustini wrote:
> On Tue, Jun 09, 2026 at 08:28:09AM -0700, Reinette Chatre wrote:
>> - I see that the default of zero for the MIN control can be appropriate. For the
>> usage of resctrl_get_default_ctrlval() when creating a new control group this
>> could be ok as a general setting since the user is expected to, after creating
>> the resource group, adjust control values as required by the workloads it will
>> contain. I need to make sure about this from all architectures and if 0 is not
>> ok then we could use Drew's suggestion of architecture providing a specific reset
>> value.
>
> Unfortunately, 0 will not work for the default value for Reserved
> bandwidth Blocks (Rbwb) in RISC-V CBQRI as it is required by the spec to
> be at least 1.

My mistake, I should not have written a hardcoded 0 but instead mirrored Ben's original
suggestion of using ctrl->membw.min_bw.

Reinette