Re: [PATCH v5 5/7] drm/amdgpu: get rid of amdgpu_ttm_clear_buffer

["Christian König" <christian.koenig@amd.com>]

On 4/7/26 12:09, Christian König wrote:
> 
> 
> On 4/3/26 10:35, Pierre-Eric Pelloux-Prayer wrote:
>> It's doing the same thing as amdgpu_fill_buffer(src_data=0), so drop it.
>>
>> The only caveat is that amdgpu_res_cleared() return value is only valid
>> right after allocation.
>>
>> ---
>> v2: introduce new "bool consider_clear_status" arg
>> ---
>>
>> Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 16 ++--
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 88 +++++-----------------
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h    |  6 +-
>>  3 files changed, 32 insertions(+), 78 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index 66c20dd46d12..d0884bbffa75 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -717,13 +717,17 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
>>  	    bo->tbo.resource->mem_type == TTM_PL_VRAM) {
>>  		struct dma_fence *fence;
>>  
>> -		r = amdgpu_ttm_clear_buffer(bo, bo->tbo.base.resv, &fence);
>> +		r = amdgpu_fill_buffer(amdgpu_ttm_next_clear_entity(adev),
>> +				       bo, 0, NULL, &fence,
>> +				       true, AMDGPU_KERNEL_JOB_ID_TTM_CLEAR_BUFFER);
>>  		if (unlikely(r))
>>  			goto fail_unreserve;
>>  
>> -		dma_resv_add_fence(bo->tbo.base.resv, fence,
>> -				   DMA_RESV_USAGE_KERNEL);
>> -		dma_fence_put(fence);
>> +		if (fence) {
>> +			dma_resv_add_fence(bo->tbo.base.resv, fence,
>> +					   DMA_RESV_USAGE_KERNEL);
>> +			dma_fence_put(fence);
>> +		}
>>  	}
>>  	if (!bp->resv)
>>  		amdgpu_bo_unreserve(bo);
>> @@ -1326,8 +1330,8 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
>>  		goto out;
>>  
>>  	r = amdgpu_fill_buffer(amdgpu_ttm_next_clear_entity(adev),
>> -			       abo, 0, &bo->base._resv,
>> -			       &fence, AMDGPU_KERNEL_JOB_ID_CLEAR_ON_RELEASE);
>> +			       abo, 0, &bo->base._resv, &fence,
>> +			       false, AMDGPU_KERNEL_JOB_ID_CLEAR_ON_RELEASE);
>>  	if (WARN_ON(r))
>>  		goto out;
>>  
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index 648ad344e89c..a3d0998b8cec 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -418,7 +418,7 @@ static int amdgpu_move_blit(struct ttm_buffer_object *bo,
>>  	    (abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE)) {
>>  		struct dma_fence *wipe_fence = NULL;
>>  		r = amdgpu_fill_buffer(entity, abo, 0, NULL, &wipe_fence,
>> -				       AMDGPU_KERNEL_JOB_ID_MOVE_BLIT);
>> +				       false, AMDGPU_KERNEL_JOB_ID_MOVE_BLIT);
>>  		if (r) {
>>  			goto error;
>>  		} else if (wipe_fence) {
>> @@ -2572,76 +2572,25 @@ static int amdgpu_ttm_fill_mem(struct amdgpu_device *adev,
>>  }
>>  
>>  /**
>> - * amdgpu_ttm_clear_buffer - clear memory buffers
>> - * @bo: amdgpu buffer object
>> - * @resv: reservation object
>> - * @fence: dma_fence associated with the operation
>> + * amdgpu_fill_buffer - fill a buffer with a given value
>> + * @entity: entity to use
>> + * @bo: the bo to fill
>> + * @src_data: the value to set
>> + * @resv: fences contained in this reservation will be used as dependencies.
>> + * @out_fence: the fence from the last clear will be stored here. It might be
>> + *             NULL if no job was run.
>> + * @dependency: optional input dependency fence.
>> + * @consider_clear_status: true if region reported as cleared by amdgpu_res_cleared()
>> + *                         are skipped.
>> + * @k_job_id: trace id
>>   *
>> - * Clear the memory buffer resource.
>> - *
>> - * Returns:
>> - * 0 for success or a negative error code on failure.
>>   */
>> -int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
>> -			    struct dma_resv *resv,
>> -			    struct dma_fence **fence)
>> -{
>> -	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>> -	struct amdgpu_ttm_buffer_entity *entity;
>> -	struct amdgpu_res_cursor cursor;
>> -	u64 addr;
>> -	int r = 0;
>> -
>> -	if (!adev->mman.buffer_funcs_enabled)
>> -		return -EINVAL;
>> -
>> -	if (!fence)
>> -		return -EINVAL;
>> -	entity = &adev->mman.clear_entities[0];
>> -	*fence = dma_fence_get_stub();
>> -
>> -	amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &cursor);
>> -
>> -	mutex_lock(&entity->lock);
>> -	while (cursor.remaining) {
>> -		struct dma_fence *next = NULL;
>> -		u64 size;
>> -
>> -		if (amdgpu_res_cleared(&cursor)) {
>> -			amdgpu_res_next(&cursor, cursor.size);
>> -			continue;
>> -		}
>> -
>> -		/* Never clear more than 256MiB at once to avoid timeouts */
>> -		size = min(cursor.size, 256ULL << 20);
>> -
>> -		r = amdgpu_ttm_map_buffer(entity, &bo->tbo, bo->tbo.resource, &cursor,
>> -					  0, false, &size, &addr);
>> -		if (r)
>> -			goto err;
>> -
>> -		r = amdgpu_ttm_fill_mem(adev, entity, 0, addr, size, resv,
>> -					&next, true,
>> -					AMDGPU_KERNEL_JOB_ID_TTM_CLEAR_BUFFER);
>> -		if (r)
>> -			goto err;
>> -
>> -		dma_fence_put(*fence);
>> -		*fence = next;
>> -
>> -		amdgpu_res_next(&cursor, size);
>> -	}
>> -err:
>> -	mutex_unlock(&entity->lock);
>> -
>> -	return r;
>> -}
>> -
>>  int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
> 
> We should probably rename the function to amdgpu_ttm_clear_buffer() while doing this.

Forget that, I've just seen that patch #6 does exactly that.

Feel free to add Reviewed-by: Christian König <christian.koenig@amd.com>.

Regards,
Christian.

> 
> Apart from that looks good to me.
> 
> Regards,
> Christian.
> 
>>  		       struct amdgpu_bo *bo,
>>  		       uint32_t src_data,
>>  		       struct dma_resv *resv,
>> -		       struct dma_fence **f,
>> +		       struct dma_fence **out_fence,
>> +		       bool consider_clear_status,
>>  		       u64 k_job_id)
>>  {
>>  	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>> @@ -2659,6 +2608,11 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
>>  		struct dma_fence *next;
>>  		uint64_t cur_size, to;
>>  
>> +		if (consider_clear_status && amdgpu_res_cleared(&dst)) {
>> +			amdgpu_res_next(&dst, dst.size);
>> +			continue;
>> +		}
>> +
>>  		/* Never fill more than 256MiB at once to avoid timeouts */
>>  		cur_size = min(dst.size, 256ULL << 20);
>>  
>> @@ -2680,9 +2634,7 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
>>  	}
>>  error:
>>  	mutex_unlock(&entity->lock);
>> -	if (f)
>> -		*f = dma_fence_get(fence);
>> -	dma_fence_put(fence);
>> +	*out_fence = fence;
>>  	return r;
>>  }
>>  
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> index a6249252948b..436a3e09a178 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> @@ -187,14 +187,12 @@ int amdgpu_copy_buffer(struct amdgpu_device *adev,
>>  		       struct dma_resv *resv,
>>  		       struct dma_fence **fence,
>>  		       bool vm_needs_flush, uint32_t copy_flags);
>> -int amdgpu_ttm_clear_buffer(struct amdgpu_bo *bo,
>> -			    struct dma_resv *resv,
>> -			    struct dma_fence **fence);
>>  int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
>>  		       struct amdgpu_bo *bo,
>>  		       uint32_t src_data,
>>  		       struct dma_resv *resv,
>> -		       struct dma_fence **f,
>> +		       struct dma_fence **out_fence,
>> +		       bool consider_clear_status,
>>  		       u64 k_job_id);
>>  struct amdgpu_ttm_buffer_entity *amdgpu_ttm_next_clear_entity(struct amdgpu_device *adev);
>>  
>