Re: [RFC PATCH 13/19] x86/resctrl: Add PLZA state tracking and context switch handling

[Reinette Chatre]

On 2/19/26 10:12 AM, Luck, Tony wrote:
> On Thu, Feb 19, 2026 at 11:06:14AM +0000, Ben Horgan wrote:
>> If we are going to add more files to resctrl we should perhaps think of
>> a reserved prefix so they won't conflict with the names of user created
>> CTRL_MON groups.
> 
> Good idea. Since these new files/directories are associated with some
> resctrl internals, perhaps the reserved prefix could be "resctrl_".
> 
> Plausibly someone might be naming their CTRL_MON groups with this
> prefix, I'd hope that the redundancy in full pathnames like:
> 
> 	/sys/fs/resctrl/resctrl_xxx
> 
> would have deterred them from such a choice.
> 
> But I'm generally bad at naming things, so other suggestions welcome
> (as long as this doesn't turn into a protracted bike-shedding event :-)

I do not see how we can invent a new prefix after the fact. We cannot
dictate what version of tooling user space will run and we cannot just
retroactively go change the documentation that has been in the kernel for
many versions. Looking at documentation of what user expects today is that
"Resource groups are represented as directories in the resctrl file system".
There is no flexibility here to add directories that mean something else.

Please keep existing user space in mind in proposals. [1] marches forward
ignoring previous comments from this discussion on how existing user space is
impacted without addressing those comments on why such changes are acceptable.

Reinette

[1] https://lore.kernel.org/lkml/aZXsihgl0B-o1DI6@agluck-desk3/