[PATCH libdrm 2/4] amdgpu: add a function to find bo by cpu mapping (v2)

[zhoucm1]

On 2018年08月08日 12:08, Junwei Zhang wrote:
> Userspace needs to know if the user memory is from BO or malloc.
>
> v2: update mutex range and rebase
>
> Signed-off-by: Junwei Zhang <Jerry.Zhang at amd.com>
> ---
>   amdgpu/amdgpu.h    | 23 +++++++++++++++++++++++
>   amdgpu/amdgpu_bo.c | 34 ++++++++++++++++++++++++++++++++++
>   2 files changed, 57 insertions(+)
>
> diff --git a/amdgpu/amdgpu.h b/amdgpu/amdgpu.h
> index be83b45..a8c353c 100644
> --- a/amdgpu/amdgpu.h
> +++ b/amdgpu/amdgpu.h
> @@ -678,6 +678,29 @@ int amdgpu_create_bo_from_user_mem(amdgpu_device_handle dev,
>   				    amdgpu_bo_handle *buf_handle);
>   
>   /**
> + * Validate if the user memory comes from BO
> + *
> + * \param dev - [in] Device handle. See #amdgpu_device_initialize()
> + * \param cpu - [in] CPU address of user allocated memory which we
> + * want to map to GPU address space (make GPU accessible)
> + * (This address must be correctly aligned).
> + * \param size - [in] Size of allocation (must be correctly aligned)
> + * \param buf_handle - [out] Buffer handle for the userptr memory
> + * if the user memory is not from BO, the buf_handle will be NULL.
> + * \param offset_in_bo - [out] offset in this BO for this user memory
> + *
> + *
> + * \return   0 on success\n
> + *          <0 - Negative POSIX Error code
> + *
> +*/
> +int amdgpu_find_bo_by_cpu_mapping(amdgpu_device_handle dev,
> +				  void *cpu,
> +				  uint64_t size,
> +				  amdgpu_bo_handle *buf_handle,
> +				  uint64_t *offset_in_bo);
> +
> +/**
>    * Free previosuly allocated memory
>    *
>    * \param   dev	       - \c [in] Device handle. See #amdgpu_device_initialize()
> diff --git a/amdgpu/amdgpu_bo.c b/amdgpu/amdgpu_bo.c
> index b24e698..a7f0662 100644
> --- a/amdgpu/amdgpu_bo.c
> +++ b/amdgpu/amdgpu_bo.c
> @@ -529,6 +529,40 @@ int amdgpu_bo_wait_for_idle(amdgpu_bo_handle bo,
>   	}
>   }
>   
> +int amdgpu_find_bo_by_cpu_mapping(amdgpu_device_handle dev,
> +				  void *cpu,
> +				  uint64_t size,
> +				  amdgpu_bo_handle *buf_handle,
> +				  uint64_t *offset_in_bo)
> +{
> +	int i;
> +	struct amdgpu_bo *bo;
> +
> +	if (cpu == NULL || size == 0)
> +		return -EINVAL;
> +
> +	pthread_mutex_lock(&dev->bo_table_mutex);
> +	for (i = 0; i < dev->bo_handles.max_key; i++) {
Hi Jerry,

As Christian catched before, iterating all BOs of device will introduce 
much CPU overhead, this isn't good direction.
Since cpu virtual address is per-process, you should go to kernel to 
find them from vm tree, which obviously takes less time.

Regards,
David Zhou
> +		bo = handle_table_lookup(&dev->bo_handles, i);
> +		if (!bo || !bo->cpu_ptr || size > bo->alloc_size)
> +			continue;
> +		if (cpu >= bo->cpu_ptr && cpu < (bo->cpu_ptr + bo->alloc_size))
> +			break;
> +	}
> +
> +	if (i < dev->bo_handles.max_key) {
> +		atomic_inc(&bo->refcount);
> +		*buf_handle = bo;
> +		*offset_in_bo = cpu - bo->cpu_ptr;
> +	} else {
> +		*buf_handle = NULL;
> +		*offset_in_bo = 0;
> +	}
> +	pthread_mutex_unlock(&dev->bo_table_mutex);
> +
> +	return 0;
> +}
> +
>   int amdgpu_create_bo_from_user_mem(amdgpu_device_handle dev,
>   				    void *cpu,
>   				    uint64_t size,