Re: [PATCH v2 29/35] fs/resctrl: Add boiler plate for external resctrl code

[James Morse <james.morse@arm.com>]

Hi Dave,

On 26/04/2024 16:08, Dave Martin wrote:
> From: James Morse <james.morse@arm.com>
> 
> Add Makefile and Kconfig for fs/resctrl. Add ARCH_HAS_CPU_RESCTRL
> for the common parts of the resctrl interface and make X86_CPU_RESCTRL
> depend on this.


> FYI: Dave Martin, James Morse (et al.):
> 
>  * Review the new Kconfig RESCTRL_FS help text.
> 
>  * Because RESCTRL_FS combines a userspace interface and a kernel
>    library providing services to its own backends, there is a circular
>    dependency between this option and the arch-specific options
>    (CONFIG_X86_RESCTRL and eventually CONFIG_ARM64_MPAM) that
>    nastifies the presentation of these options in Kconfig.
> 
>    Can this be improved?
> 
>    The current situation works, but is not very user-friendly for
>    menuconfig users.

I don't follow what the circular dependency is - Kconfig would bark if there was one.

I agree its odd that you can't disable the filesystem under the filesystem menu - but that
is so that the existing Kconfig symbol name remains the switch for this. It's possible
no-one cares about that...

A more obvious approach would be a switch for the arch hardware feature, that when enabled
allows the filesystem to be selected. This seems overkill as there is only one user.


Thanks,

James