Re: [PATCH v2 3/3] x86/resctrl: Add "*" shorthand to set minimum io_alloc CBM for all domains

From: Aaron Tomlin
Date: Thu Dec 25 2025 - 17:50:32 EST


On Fri, Dec 19, 2025 at 03:05:34PM -0800, Luck, Tony wrote:
> I still don't see a good reason for the kernel to handle any of this.
>
> Having some resctrl control files accept wildcards while others don't
> seems like a confusing interface. Is there something I'm missing that
> makes io_alloc harder for users to handle than L3 or MB in schemata?
>
> Babu's simpler implementation for io_alloc makes me more comfortable
> with this. But I'm still unconvinced that wildcards must be handled
> in kernel code.

Hi Tony,

I appreciate your reservations regarding where the responsibility for such
abstractions should lie. However, I am of the view that forcing the user to
manually specify every domain for a global policy represents an unnecessary
hurdle that the kernel is uniquely positioned to clear.

I shall indeed employ Babu's suggestion in a follow-up patch for review, as
the resulting simplicity of the implementation should, I hope, alleviate
any concerns regarding the addition of technical debt.


Kind regards,
--
Aaron Tomlin

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