Proposal to merge KFD into amdgpu

[Michel Dänzer]

On 2018-07-04 11:36 PM, Felix Kuehling wrote:
> Since KFD is only supported by a single GPU driver now (amdgpu), it
> makes sense to merge the two. This has been raised on the amd-gfx list
> before and I've been putting it off to avoid more churn while I was
> working on upstreaming KFD. Now seems a good time to pick this up again.
> 
> At this stage there are some things that I don't expect to change
> significantly:
> 
>   * Directory structure
>   * KFD function naming conventions
>   * KFD device and sysfs interfaces
> 
> This is a rough overview of the changes I have in mind. We should be
> able to implement these step-by-step and minimize disruption:
> 
> 1. Change the build system to build KFD into amdgpu.ko
> 
> This should make KFD similar to DAL or powerplay. It's still a mostly
> separate code base and Makefile with its own directory, but gets linked
> into amdgpu.ko.
> 
> In the kernel configuration HSA_AMD would become a boolean option under
> DRM_AMDGPU that controls whether KFD functionality gets built into amdgpu.
> 
> Any code inside #if defined(CONFIG_HSA_AMD_MODULE) can be removed.
> 
> 2. Simplify the kfd2kgd and kgd2kfg interfaces
> 
> Function pointers in struct kgd2kfd_calls are no longer needed. These
> functions can be called directly from amdgpu.
> 
> Hardware-independent function pointers in kfd2kgd_calls are no longer
> needed. These function can be called directly from amdkfd. Some of the
> function pointers in kfd2kgd_calls are used for hardware abstraction
> with different implementations for each GFX HW generation. These will
> need to remain function pointers.
> 
> At some later stage, the HW-specific functions could be moved into
> gfx_v*.c and the function pointers added to struct amdgpu_gfx. But at
> this stage I think I'd leave them where they are.
> 
> 3. Reduce duplicate tracking of device and BO structures
> 
> Currently KFD and AMDGPU pretend to not know each other's data
> structures. If both are in the same module, we could allow KFD to access
> some amdgpu structures directly (e.g. amdgpu_device and amdgpu_bo). This
> way some of the duplicate tracking of devices and buffer objects could
> be eliminated.
> 
> This may present opportunities to simplify some functionality that's
> currently split across both modules, such as suspend/resume, memory
> management and evictions.
> 
> Some interfaces that just query information from amdgpu could be removed
> if KFD can access that information directly (e.g. firmware versions, CU
> info, ...).
> 
> Please let me know if you have any objections, suggestions, ideas ...

Thumbs up from me! :)


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer