On 13/11/2025 18:45, Akash Goel wrote: > The kernel BOs unnecessarily got added to the external objects list > of drm_gpuvm, when mapping to GPU, which would have resulted in few > extra CPU cycles being spent at the time of job submission as > drm_exec_until_all_locked() loop iterates over all external objects. > > Kernel BOs are private to a VM and so they share the dma_resv object of > the dummy GEM object created for a VM. Use of DRM_EXEC_IGNORE_DUPLICATES > flag ensured the recursive locking of the dummy GEM object was ignored. > Also no extra space got allocated to add fences to the dma_resv object > of dummy GEM object. So no other impact apart from few extra CPU cycles. > > This commit sets the pointer to dma_resv object of GEM object of > kernel BOs before they are mapped to GPU, to prevent them from > being added to external objects list. > > Signed-off-by: Akash Goel <[email protected]>
Reviewed-by: Steven Price <[email protected]> As Boris says it would be good to have a Fixes tag - can you dig out an appropriate commit then I can merge? Thanks, Steve > --- > drivers/gpu/drm/panthor/panthor_gem.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c > b/drivers/gpu/drm/panthor/panthor_gem.c > index f369cc3e2a5f..10d255cccc09 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -145,6 +145,9 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, > struct panthor_vm *vm, > bo = to_panthor_bo(&obj->base); > kbo->obj = &obj->base; > bo->flags = bo_flags; > + bo->exclusive_vm_root_gem = panthor_vm_root_gem(vm); > + drm_gem_object_get(bo->exclusive_vm_root_gem); > + bo->base.base.resv = bo->exclusive_vm_root_gem->resv; > > if (vm == panthor_fw_vm(ptdev)) > debug_flags |= PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED; > @@ -168,9 +171,6 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, > struct panthor_vm *vm, > goto err_free_va; > > kbo->vm = panthor_vm_get(vm); > - bo->exclusive_vm_root_gem = panthor_vm_root_gem(vm); > - drm_gem_object_get(bo->exclusive_vm_root_gem); > - bo->base.base.resv = bo->exclusive_vm_root_gem->resv; > return kbo; > > err_free_va:
