Re: [PATCH 3/6] drm/amdkfd: Improve amdgpu_vm_handle_moved

["Chen, Xiaogang" <xiaogang.chen@xxxxxxx>]

Acked-by: Xiaogang Chen

Regards

Xiaogang

On 1/11/2023 7:31 PM, Felix Kuehling wrote:
> Let amdgpu_vm_handle_moved update all BO VA mappings of BOs reserved by
> the caller. This will be useful for handling extra BO VA mappings in
> KFD VMs that are managed through the render node API.
>
> Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> Reviewed-by: Christian König <christian.koenig@xxxxxxx>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c      |  6 +++++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c |  2 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c      | 18 +++++++++++++-----
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h      |  3 ++-
>   4 files changed, 21 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 275da612cd87..a80d2557edb2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -1121,6 +1121,10 @@ static int amdgpu_cs_vm_handling(struct amdgpu_cs_parser *p)
>   			return r;
>   	}
>   
> +	/* TODO: Is this loop still needed, or could this be handled by
> +	 * amdgpu_vm_handle_moved, now that it can handle all BOs that are
> +	 * reserved under p->ticket?
> +	 */
>   	amdgpu_bo_list_for_each_entry(e, p->bo_list) {
>   		/* ignore duplicates */
>   		bo = ttm_to_amdgpu_bo(e->tv.bo);
> @@ -1140,7 +1144,7 @@ static int amdgpu_cs_vm_handling(struct amdgpu_cs_parser *p)
>   			return r;
>   	}
>   
> -	r = amdgpu_vm_handle_moved(adev, vm);
> +	r = amdgpu_vm_handle_moved(adev, vm, &p->ticket);
>   	if (r)
>   		return r;
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index 271e30e34d93..23a213e4ab2c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -404,7 +404,7 @@ amdgpu_dma_buf_move_notify(struct dma_buf_attachment *attach)
>   
>   		r = amdgpu_vm_clear_freed(adev, vm, NULL);
>   		if (!r)
> -			r = amdgpu_vm_handle_moved(adev, vm);
> +			r = amdgpu_vm_handle_moved(adev, vm, ticket);
>   
>   		if (r && r != -EBUSY)
>   			DRM_ERROR("Failed to invalidate VM page tables (%d))\n",
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index dc379dc22c77..75dae2850e75 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1286,11 +1286,12 @@ int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
>    * PTs have to be reserved!
>    */
>   int amdgpu_vm_handle_moved(struct amdgpu_device *adev,
> -			   struct amdgpu_vm *vm)
> +			   struct amdgpu_vm *vm,
> +			   struct ww_acquire_ctx *ticket)
>   {
>   	struct amdgpu_bo_va *bo_va;
>   	struct dma_resv *resv;
> -	bool clear;
> +	bool clear, unlock;
>   	int r;
>   
>   	spin_lock(&vm->status_lock);
> @@ -1313,17 +1314,24 @@ int amdgpu_vm_handle_moved(struct amdgpu_device *adev,
>   		spin_unlock(&vm->status_lock);
>   
>   		/* Try to reserve the BO to avoid clearing its ptes */
> -		if (!amdgpu_vm_debug && dma_resv_trylock(resv))
> +		if (!amdgpu_vm_debug && dma_resv_trylock(resv)) {
>   			clear = false;
> +			unlock = true;
> +		/* The caller is already holding the reservation lock */
> +		} else if (ticket && dma_resv_locking_ctx(resv) == ticket) {
> +			clear = false;
> +			unlock = false;
>   		/* Somebody else is using the BO right now */
> -		else
> +		} else {
>   			clear = true;
> +			unlock = false;
> +		}
>   
>   		r = amdgpu_vm_bo_update(adev, bo_va, clear);
>   		if (r)
>   			return r;
>   
> -		if (!clear)
> +		if (unlock)
>   			dma_resv_unlock(resv);
>   		spin_lock(&vm->status_lock);
>   	}
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> index 094bb4807303..03a3314e5b43 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -400,7 +400,8 @@ int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
>   			  struct amdgpu_vm *vm,
>   			  struct dma_fence **fence);
>   int amdgpu_vm_handle_moved(struct amdgpu_device *adev,
> -			   struct amdgpu_vm *vm);
> +			   struct amdgpu_vm *vm,
> +			   struct ww_acquire_ctx *ticket);
>   void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
>   			    struct amdgpu_vm *vm, struct amdgpu_bo *bo);
>   int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm,