Messages in this thread | | | Date | Mon, 11 Sep 2023 20:37:44 +0200 | Subject | Re: [PATCH drm-misc-next v3 5/7] drm/gpuvm: add an abstraction for a VM / BO combination | From | Thomas Hellström <> |
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On 9/11/23 19:49, Danilo Krummrich wrote: > 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.
Ah OK. Thanks, I'll take a deeper look.
/Thomas
> > - Danilo > >> >> Thanks, >> >> Thomas >> >> >
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