Messages in this thread | | | Date | Mon, 11 Sep 2023 19:49:04 +0200 | Subject | Re: [PATCH drm-misc-next v3 5/7] drm/gpuvm: add an abstraction for a VM / BO combination | From | Danilo Krummrich <> |
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Hi Thomas,
On 9/11/23 19:19, Thomas Hellström wrote: > Hi, Danilo > > On 9/9/23 17:31, Danilo Krummrich wrote: >> This patch adds an abstraction layer between the drm_gpuva mappings of >> a particular drm_gem_object and this GEM object itself. The abstraction >> represents a combination of a drm_gem_object and drm_gpuvm. The >> drm_gem_object holds a list of drm_gpuvm_bo structures (the structure >> representing this abstraction), while each drm_gpuvm_bo contains list of >> mappings of this GEM object. >> >> This has multiple advantages: >> >> 1) We can use the drm_gpuvm_bo structure to attach it to various lists >> of the drm_gpuvm. This is useful for tracking external and evicted >> objects per VM, which is introduced in subsequent patches. >> >> 2) Finding mappings of a certain drm_gem_object mapped in a certain >> drm_gpuvm becomes much cheaper. >> >> 3) Drivers can derive and extend the structure to easily represent >> driver specific states of a BO for a certain GPUVM. >> >> The idea of this abstraction was taken from amdgpu, hence the credit for >> this idea goes to the developers of amdgpu. >> >> Cc: Christian König <christian.koenig@amd.com> >> Signed-off-by: Danilo Krummrich <dakr@redhat.com> > > Did you consider having the drivers embed the struct drm_gpuvm_bo in their own bo definition? I figure that would mean using the gem bo's refcounting and providing a helper to call from the driver's bo release. Looks like that could potentially save a lot of code? Or is there something that won't work with that approach?
There are drm_gpuvm_ops::vm_bo_alloc and drm_gpuvm_ops::vm_bo_free callback for drivers to register for that purpose.
- Danilo
> > Thanks, > > Thomas > >
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