[Linaro-mm-sig] Re: [PATCH v1 17/20] drm/amdgpu: get rid of amdgpu_ttm_clear_buffer

On 11/4/25 09:35, 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.

Signed-off-by: Pierre-Eric Pelloux-Prayer pierre-eric.pelloux-prayer@amd.com

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 9 +-- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 86 ++++------------------ drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 3 - 3 files changed, 18 insertions(+), 80 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c index 4a69324bb730..410e9b68ff81 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c @@ -723,15 +723,10 @@ int amdgpu_bo_create(struct amdgpu_device *adev, if (bp->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED && 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(NULL, bo, 0, NULL,
  

• 		       NULL, 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 (!bp->resv) amdgpu_bo_unreserve(bo);

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index d88bdb2ac083..1f553c56f31d 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -2412,75 +2412,6 @@ static int amdgpu_ttm_fill_mem(struct amdgpu_ring *ring, return 0; } -/**

• • amdgpu_ttm_clear_buffer - clear memory buffers
• • @bo: amdgpu buffer object
• • @resv: reservation object
• • @fence: dma_fence associated with the operation
• • 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_ring *ring = adev->mman.buffer_funcs_rings[0];
• struct amdgpu_ttm_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->gart_window_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->base,
  

• 			  &bo->tbo, bo->tbo.resource, &cursor,
  

• 			  entity->gart_window_id1, ring, false, &size, &addr,
  

• 			  NULL, NULL);
  

• if (r)
  

• 	goto err;
  

• r = amdgpu_ttm_fill_mem(ring, &entity->base, 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->gart_window_lock);
• return r;

-}

/**

• amdgpu_fill_buffer - fill a buffer with a given value
• @entity: optional entity to use. If NULL, the clearing entities will be

@@ -2508,6 +2439,9 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_entity *entity, struct amdgpu_res_cursor dst; uint64_t cur_size, to; int r, e, n_fences;

• /* The clear flag is only valid directly after allocation. */
• bool consider_clear_flag =

• src_data == 0 && k_job_id == AMDGPU_KERNEL_JOB_ID_TTM_CLEAR_BUFFER;
  

Absolutely clear NAK to that.

Christian.

/* The fences will be either added to the resv object or the last fence * will be returned to the caller. In the latter case, all fill jobs will @@ -2531,6 +2465,11 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_entity *entity, while (dst.remaining) { cur_size = min(dst.size, 256ULL << 20);

• 	if (consider_clear_flag && amdgpu_res_cleared(&dst)) {
  

• 		amdgpu_res_next(&dst, dst.size);
  

• 		continue;
  

• 	}
  

• n_fences += 1;
  amdgpu_res_next(&dst, cur_size);
  

  }

@@ -2550,6 +2489,11 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_entity *entity, amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &dst); while (dst.remaining) {

• if (consider_clear_flag && 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);

@@ -2574,8 +2518,10 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_entity *entity, goto error; }

• r = amdgpu_ttm_fill_mem(ring, &entity->base,

• 			src_data, to, cur_size, resv,
  

• 			src_data, to, cur_size,
  

• 			resv,
  		&fence, true, k_job_id);
  

  if (r) { mutex_unlock(&entity->gart_window_lock);

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h index c059a3d52b57..97e73919cb0c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h @@ -182,9 +182,6 @@ int amdgpu_copy_buffer(struct amdgpu_ring *ring, 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_entity *entity, struct amdgpu_bo *bo, uint32_t src_data,