Requirements to merge new heaps in the kernel

[John Stultz]

On Tue, Oct 22, 2024 at 1:38 AM Maxime Ripard <mripard at redhat.com> wrote:
>
> I wanted to follow-up on the discussion we had at Plumbers with John and
> T.J. about (among other things) adding new heaps to the kernel.
>
> I'm still interested in merging a carve-out driver[1], since it seems to be
> in every vendor BSP and got asked again last week.
>
> I remember from our discussion that for new heap types to be merged, we
> needed a kernel use-case. Looking back, I'm not entirely sure how one
> can provide that given that heaps are essentially facilities for
> user-space.
>
> Am I misremembering or missing something? What are the requirements for
> you to consider adding a new heap driver?

It's basically the same as the DRM subsystem rules.
https://docs.kernel.org/gpu/drm-uapi.html#open-source-userspace-requirements
ie: There has to be opensource user for it, and the user has to be
more significant than a "toy" implementation (which can be a bit
subjective and contentious when trying to get out of a chicken and egg
loop).

thanks
-john