[PATCH] drm/amdkfd: allocate MMIO/DOORBELL BOs with AMDGPU_GEM_CREATE_PREEMPTIBLE

[Felix Kuehling]

On 2022-05-11 05:44, Lang Yu wrote:
> MMIO/DOORBELL BOs' backing resources(bus address resources that are
> used to talk to the GPU) are not managed by GTT manager, but they
> are counted by GTT manager. That makes no sense.
>
> With AMDGPU_GEM_CREATE_PREEMPTIBLE flag, such BOs will be managed by
> PREEMPT manager(for preemptible contexts, e.g., KFD). Then they won't
> be evicted and don't need to be pinned as well.
>
> But we still leave these BOs pinned to indicate that the underlying
> resource never moves.
>
> Signed-off-by: Lang Yu <Lang.Yu at amd.com>

Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>


> ---
>   .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 32 +++++++++----------
>   1 file changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> index 8b14c55a0793..fada3b149361 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> @@ -1518,26 +1518,26 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
>   	} else if (flags & KFD_IOC_ALLOC_MEM_FLAGS_GTT) {
>   		domain = alloc_domain = AMDGPU_GEM_DOMAIN_GTT;
>   		alloc_flags = 0;
> -	} else if (flags & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
> +	} else {
>   		domain = AMDGPU_GEM_DOMAIN_GTT;
>   		alloc_domain = AMDGPU_GEM_DOMAIN_CPU;
>   		alloc_flags = AMDGPU_GEM_CREATE_PREEMPTIBLE;
> -		if (!offset || !*offset)
> -			return -EINVAL;
> -		user_addr = untagged_addr(*offset);
> -	} else if (flags & (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> -			KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
> -		domain = AMDGPU_GEM_DOMAIN_GTT;
> -		alloc_domain = AMDGPU_GEM_DOMAIN_CPU;
> -		bo_type = ttm_bo_type_sg;
> -		alloc_flags = 0;
> -		if (size > UINT_MAX)
> +
> +		if (flags & KFD_IOC_ALLOC_MEM_FLAGS_USERPTR) {
> +			if (!offset || !*offset)
> +				return -EINVAL;
> +			user_addr = untagged_addr(*offset);
> +		} else if (flags & (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> +				    KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
> +			bo_type = ttm_bo_type_sg;
> +			if (size > UINT_MAX)
> +				return -EINVAL;
> +			sg = create_doorbell_sg(*offset, size);
> +			if (!sg)
> +				return -ENOMEM;
> +		} else {
>   			return -EINVAL;
> -		sg = create_doorbell_sg(*offset, size);
> -		if (!sg)
> -			return -ENOMEM;
> -	} else {
> -		return -EINVAL;
> +		}
>   	}
>   
>   	*mem = kzalloc(sizeof(struct kgd_mem), GFP_KERNEL);