[PATCH v2 04/10] drm/amdgpu: Simplify AQL queue mapping

Zeng, Oak Oak.Zeng at amd.com
Fri Apr 23 01:33:57 UTC 2021



Regards,
Oak 

 

On 2021-04-21, 9:31 PM, "amd-gfx on behalf of Felix Kuehling" <amd-gfx-bounces at lists.freedesktop.org on behalf of Felix.Kuehling at amd.com> wrote:

    Do AQL queue double-mapping with a single attach call. That will make it
    easier to create per-GPU BOs later, to be shared between the two BO VA
    mappings on the same GPU.

    Freeing the attachments is not necessary if map_to_gpu fails. These will be
    cleaned up when the kdg_mem object is destroyed in
    amdgpu_amdkfd_gpuvm_free_memory_of_gpu.

    Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
    ---
     .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 103 ++++++++----------
     1 file changed, 48 insertions(+), 55 deletions(-)

    diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
    index 34c9a2d0028e..fbd7e786b54e 100644
    --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
    +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
    @@ -486,70 +486,76 @@ static uint64_t get_pte_flags(struct amdgpu_device *adev, struct kgd_mem *mem)
      * 4a.  Validate new page tables and directories
      */
     static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem,
    -		struct amdgpu_vm *vm, bool is_aql,
    -		struct kfd_mem_attachment **p_attachment)
    +		struct amdgpu_vm *vm, bool is_aql)
     {
     	unsigned long bo_size = mem->bo->tbo.base.size;
     	uint64_t va = mem->va;
    -	struct kfd_mem_attachment *attachment;
    -	struct amdgpu_bo *bo;
    -	int ret;
    +	struct kfd_mem_attachment *attachment[2] = {NULL, NULL};
    +	struct amdgpu_bo *bo[2] = {NULL, NULL};
    +	int i, ret;

     	if (!va) {
     		pr_err("Invalid VA when adding BO to VM\n");
     		return -EINVAL;
     	}

    -	if (is_aql)
    -		va += bo_size;
    -
    -	attachment = kzalloc(sizeof(*attachment), GFP_KERNEL);
    -	if (!attachment)
    -		return -ENOMEM;
    +	for (i = 0; i <= is_aql; i++) {
    +		attachment[i] = kzalloc(sizeof(*attachment[i]), GFP_KERNEL);
    +		if (unlikely(!attachment[i])) {
    +			ret = -ENOMEM;
    +			goto unwind;
    +		}

    -	pr_debug("\t add VA 0x%llx - 0x%llx to vm %p\n", va,
    -			va + bo_size, vm);
    +		pr_debug("\t add VA 0x%llx - 0x%llx to vm %p\n", va,
    +			 va + bo_size, vm);

    -	/* FIXME: For now all attachments use the same BO. This is incorrect
    -	 * because one BO can only have one DMA mapping for one GPU. We need
    -	 * one BO per GPU, e.g. a DMABuf import with dynamic attachment. This
    -	 * will be addressed one BO-type at a time in subsequent patches.
    -	 */
    -	bo = mem->bo;
    -	drm_gem_object_get(&bo->tbo.base);
    +		/* FIXME: For now all attachments use the same BO. This is
    +		 * incorrect because one BO can only have one DMA mapping
    +		 * for one GPU. We need one BO per GPU, e.g. a DMABuf
    +		 * import with dynamic attachment. This will be addressed
    +		 * one BO-type at a time in subsequent patches.
    +		 */
    +		bo[i] = mem->bo;
    +		drm_gem_object_get(&bo[i]->tbo.base);

    -	/* Add BO to VM internal data structures*/
    -	attachment->bo_va = amdgpu_vm_bo_add(adev, vm, bo);
    -	if (!attachment->bo_va) {
    -		ret = -EINVAL;
    -		pr_err("Failed to add BO object to VM. ret == %d\n",
    -				ret);
    -		goto err_vmadd;
    -	}
    +		/* Add BO to VM internal data structures */
    +		attachment[i]->bo_va = amdgpu_vm_bo_add(adev, vm, bo[i]);
Just for discussion. Are we allowed to add one bo twice to a vm? When I looked at amdgpu_vm_bo_base_init (called by amdgpu_vm_bo_add), line:
bo->vm_bo = base;
when you add the same bo to vm the second time, bo->vm_bo will be overwritten. I am not sure whether this will cause an issue later.
This is not introduced by your code. The original code (calling kfd_mem_attach twice for aql) has the same problem.
    +		if (unlikely(!attachment[i]->bo_va)) {
    +			ret = -ENOMEM;
    +			pr_err("Failed to add BO object to VM. ret == %d\n",
    +			       ret);
    +			goto unwind;
    +		}

    -	attachment->va = va;
    -	attachment->pte_flags = get_pte_flags(adev, mem);
    -	attachment->adev = adev;
    -	list_add(&attachment->list, &mem->attachments);
    +		attachment[i]->va = va;
    +		attachment[i]->pte_flags = get_pte_flags(adev, mem);
    +		attachment[i]->adev = adev;
    +		list_add(&attachment[i]->list, &mem->attachments);

    -	if (p_attachment)
    -		*p_attachment = attachment;
    +		va += bo_size;
    +	}

     	/* Allocate validate page tables if needed */
     	ret = vm_validate_pt_pd_bos(vm);
     	if (unlikely(ret)) {
     		pr_err("validate_pt_pd_bos() failed\n");
    -		goto err_alloc_pts;
    +		goto unwind;
     	}

     	return 0;

    -err_alloc_pts:
    -	amdgpu_vm_bo_rmv(adev, attachment->bo_va);
    -	list_del(&attachment->list);
    -err_vmadd:
    -	drm_gem_object_put(&bo->tbo.base);
    -	kfree(attachment);
    +unwind:
    +	for (; i >= 0; i--) {
    +		if (!attachment[i])
    +			continue;
    +		if (attachment[i]->bo_va) {
    +			amdgpu_vm_bo_rmv(adev, attachment[i]->bo_va);
    +			list_del(&attachment[i]->list);
    +		}
    +		if (bo[i])
    +			drm_gem_object_put(&bo[i]->tbo.base);
    +		kfree(attachment[i]);
    +	}
     	return ret;
     }

    @@ -1382,8 +1388,6 @@ int amdgpu_amdkfd_gpuvm_map_memory_to_gpu(
     	uint32_t domain;
     	struct kfd_mem_attachment *entry;
     	struct bo_vm_reservation_context ctx;
    -	struct kfd_mem_attachment *attachment = NULL;
    -	struct kfd_mem_attachment *attachment_aql = NULL;
     	unsigned long bo_size;
     	bool is_invalid_userptr = false;

    @@ -1433,15 +1437,9 @@ int amdgpu_amdkfd_gpuvm_map_memory_to_gpu(
     		is_invalid_userptr = true;

     	if (!kfd_mem_is_attached(avm, mem)) {
    -		ret = kfd_mem_attach(adev, mem, avm, false, &attachment);
    +		ret = kfd_mem_attach(adev, mem, avm, mem->aql_queue);
     		if (ret)
     			goto attach_failed;
    -		if (mem->aql_queue) {
    -			ret = kfd_mem_attach(adev, mem, avm, true,
    -					     &attachment_aql);
    -			if (ret)
    -				goto attach_failed_aql;
    -		}
     	} else {
     		ret = vm_validate_pt_pd_bos(avm);
     		if (unlikely(ret))
    @@ -1496,11 +1494,6 @@ int amdgpu_amdkfd_gpuvm_map_memory_to_gpu(
     	goto out;

     map_bo_to_gpuvm_failed:
    -	if (attachment_aql)
    -		kfd_mem_detach(attachment_aql);
    -attach_failed_aql:
    -	if (attachment)
    -		kfd_mem_detach(attachment);
     attach_failed:
     	unreserve_bo_and_vms(&ctx, false, false);
     out:
    -- 
    2.31.1

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