[PATCH v2 11/20] drm/amdgpu: round robin through clear_entities in amdgpu_fill_buffer

Pierre-Eric Pelloux-Prayer
2025-11-13T16:10:32Z

This makes clear of different BOs run in parallel. Partial jobs to
clear a single BO still execute sequentially.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 9 ++++++++-
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 1 +
3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index be3532134e46..33b397107778 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1321,7 +1321,7 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
if (r)
goto out;

- r = amdgpu_fill_buffer(&adev->mman.clear_entities[0], abo, 0, &bo->base._resv,
+ r = amdgpu_fill_buffer(NULL, abo, 0, &bo->base._resv,
&fence, NULL, 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 411997db70eb..486c701d0d5b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -2224,6 +2224,7 @@ u32 amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
adev->mman.clear_entities = kcalloc(num_clear_entities,
sizeof(struct amdgpu_ttm_buffer_entity),
GFP_KERNEL);
+ atomic_set(&adev->mman.next_clear_entity, 0);
if (!adev->mman.clear_entities)
goto error_free_entity;

@@ -2489,7 +2490,7 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
struct dma_fence *fence = NULL;
struct amdgpu_res_cursor dst;
- int r;
+ int r, e;

if (!adev->mman.buffer_funcs_enabled) {
dev_err(adev->dev,
@@ -2497,6 +2498,12 @@ int amdgpu_fill_buffer(struct amdgpu_ttm_buffer_entity *entity,
return -EINVAL;
}

+ if (entity == NULL) {
+ e = atomic_inc_return(&adev->mman.next_clear_entity) %
+ adev->mman.num_clear_entities;
+ entity = &adev->mman.clear_entities[e];
+ }
+
amdgpu_res_first(bo->tbo.resource, 0, amdgpu_bo_size(bo), &dst);

mutex_lock(&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 e8f8165f5bcf..781b0bdca56c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -73,6 +73,7 @@ struct amdgpu_mman {

struct amdgpu_ttm_buffer_entity default_entity; /* has no gart windows */
struct amdgpu_ttm_buffer_entity *clear_entities;
+ atomic_t next_clear_entity;
u32 num_clear_entities;
struct amdgpu_ttm_buffer_entity move_entities[TTM_NUM_MOVE_FENCES];
u32 num_move_entities;
--
2.43.0