search for: vm_bos

...ake on this is that it would be possible to get GPUVM to >>> work both with and without internal refcounting; If with, the driver >>> needs a vm close to resolve cyclic references, if without that's not >>> necessary. If GPUVM is allowed to refcount in mappings and vm_bos, >>> that comes with a slight performance drop but as Danilo pointed out, >>> the VM lifetime problem iterating over a vm_bo's mapping becomes >>> much easier and the code thus becomes easier to maintain moving >>> forward. That convinced me it's a go...

...e possible to get GPUVM to >>>> work both with and without internal refcounting; If with, the >>>> driver needs a vm close to resolve cyclic references, if without >>>> that's not necessary. If GPUVM is allowed to refcount in mappings >>>> and vm_bos, that comes with a slight performance drop but as Danilo >>>> pointed out, the VM lifetime problem iterating over a vm_bo's >>>> mapping becomes much easier and the code thus becomes easier to >>>> maintain moving forward. That convinced me it's a good...

...tion on this? >> >> FWIW, my take on this is that it would be possible to get GPUVM to work both with and without internal refcounting; If with, the driver needs a vm close to resolve cyclic references, if without that's not necessary. If GPUVM is allowed to refcount in mappings and vm_bos, that comes with a slight performance drop but as Danilo pointed out, the VM lifetime problem iterating over a vm_bo's mapping becomes much easier and the code thus becomes easier to maintain moving forward. That convinced me it's a good thing. > > I strongly believe you guys stumble...

...cs.close handling is something like >> asking drm_gpuvm destroying the VM_BO and getting the mappings which >> should be cleared in the page table in return. >> >> In amdgpu we even go a step further and the VM structure keeps track >> of all the mappings of deleted VM_BOs so that higher level can query >> those and clear them later on. >> >> Background is that the drm_gem_object_funcs.close can't fail, but it >> can perfectly be that the app is killed because of an OOM situation >> and we can't do page tables updates in that...

...something >>> like asking drm_gpuvm destroying the VM_BO and getting the mappings >>> which should be cleared in the page table in return. >>> >>> In amdgpu we even go a step further and the VM structure keeps track >>> of all the mappings of deleted VM_BOs so that higher level can query >>> those and clear them later on. >>> >>> Background is that the drm_gem_object_funcs.close can't fail, but it >>> can perfectly be that the app is killed because of an OOM situation >>> and we can't do page tab...