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So far the DRM GPUVA manager offers common infrastructure to track GPU VA allocations and mappings, generically connect GPU VA mappings to their backing buffers and perform more complex mapping operations on the GPU VA space. However, there are more design patterns commonly used by drivers, which can potentially be generalized in order to make the DRM GPUVA manager represent a basic GPU-VM

...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 g...

...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 goo...

...oyed. >>> >>> Certainly, that would be possible. However, thinking about it, this >>> might call for >>> huge trouble. >>> >>> First of all, we'd still need to reference count a GPUVM and take a >>> reference for each >>> VM_BO, as we do already. Now instead of simply increasing the >>> reference count for each >>> mapping as well, we'd need a *mandatory* driver callback that is >>> called when the GPUVM >>> reference count drops to zero. Maybe something like vm_destroy(). >&gt...

...gt;> Certainly, that would be possible. However, thinking about it, this >>>> might call for >>>> huge trouble. >>>> >>>> First of all, we'd still need to reference count a GPUVM and take a >>>> reference for each >>>> VM_BO, as we do already. Now instead of simply increasing the >>>> reference count for each >>>> mapping as well, we'd need a *mandatory* driver callback that is >>>> called when the GPUVM >>>> reference count drops to zero. Maybe something like vm_de...

...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 stumbl...

...1 insertion(+) diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm/nouveau/nouveau_uvmm.c index ee02cd833c5e..84a36fe7c37d 100644 --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c @@ -1803,6 +1803,7 @@ nouveau_uvmm_bo_validate(struct drm_gpuvm_bo *vm_bo, struct drm_exec *exec) { struct nouveau_bo *nvbo = nouveau_gem_object(vm_bo->obj); + nouveau_bo_placement_set(nvbo, nvbo->valid_domains, 0); return nouveau_bo_validate(nvbo, true, false); } -- 2.45.0

...s = &amdgpu_gem_object_funcs; And this should probably go into amdgpu_gem_object_create(). Apart from that looks like a good idea to me. Christian. > drm_gem_private_object_init(adev->ddev, &bo->tbo.base, size); > INIT_LIST_HEAD(&bo->shadow_list); > bo->vm_bo = NULL;

...struct drm_gpuva_manager *mgr, struct drm_gpuva *va); >>>>>>> void drm_gpuva_remove(struct drm_gpuva *va); >>>>>>> -void drm_gpuva_link(struct drm_gpuva *va); >>>>>>> +void drm_gpuva_link(struct drm_gpuva *va, struct drm_gpuva_gem *vm_bo); >>>>>>> void drm_gpuva_unlink(struct drm_gpuva *va); >>>>>>> struct drm_gpuva *drm_gpuva_find(struct drm_gpuva_manager *mgr, >>>>>>> @@ -240,15 +244,137 @@ struct drm_gpuva_manager { >>>>>>> * @op...

...t from that the patch is Reviewed-by: Christian K?nig <christian.koenig at amd.com>. But I think we need some smoke testing of it. Christian. > drm_gem_private_object_init(adev_to_drm(adev), &bo->tbo.base, size); > INIT_LIST_HEAD(&bo->shadow_list); > bo->vm_bo = NULL;

...uct amdgpu_device *adev, bo = kzalloc(sizeof(struct amdgpu_bo), GFP_KERNEL); if (bo == NULL) return -ENOMEM; + + bo->tbo.base.funcs = &amdgpu_gem_object_funcs; drm_gem_private_object_init(adev->ddev, &bo->tbo.base, size); INIT_LIST_HEAD(&bo->shadow_list); bo->vm_bo = NULL; -- 2.28.0

...allback for the GEM object? Best regards Thomas > > Apart from that looks like a good idea to me. > > Christian. > >> ????? drm_gem_private_object_init(adev->ddev, &bo->tbo.base, size); >> ????? INIT_LIST_HEAD(&bo->shadow_list); >> ????? bo->vm_bo = NULL; > -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 N?rnberg, Germany (HRB 36809, AG N?rnberg) Gesch?ftsf?hrer: Felix Imend?rffer -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc T...

...-561,6 +561,7 @@ static int amdgpu_bo_do_create(struct amdgpu_device *adev, bo = kzalloc(sizeof(struct amdgpu_bo), GFP_KERNEL); if (bo == NULL) return -ENOMEM; + drm_gem_private_object_init(adev_to_drm(adev), &bo->tbo.base, size); INIT_LIST_HEAD(&bo->shadow_list); bo->vm_bo = NULL; -- 2.28.0

The GEM and PRIME related callbacks in struct drm_driver are deprecated in favor of GEM object functions in struct drm_gem_object_funcs. This patchset converts the remaining drivers to object functions and removes most of the obsolete interfaces. Patches #1 to #18 convert DRM drivers to GEM object functions, one by one. Each patch moves existing callbacks from struct drm_driver to an instance of

The GEM and PRIME related callbacks in struct drm_driver are deprecated in favor of GEM object functions in struct drm_gem_object_funcs. This patchset converts the remaining drivers to object functions and removes most of the obsolete interfaces. Patches #1 to #16 and #18 to #19 convert DRM drivers to GEM object functions, one by one. Each patch moves existing callbacks from struct drm_driver to