[PATCH v3 4/4] drm/xe: Implement clear VRAM on free
Matthew Brost
matthew.brost at intel.com
Mon Jun 23 15:19:29 UTC 2025
Clearing on free should hide latency of BO clears on new user BO
allocations.
Implemented via calling xe_migrate_clear in release notify and updating
iterator in xe_migrate_clear to skip cleared buddy blocks. Only user BOs
cleared in release notify as kernel BOs could still be in use (e.g., PT
BOs need to wait for dma-resv to be idle).
v2:
- Update to new xe_migrate_clear arguments (Thomas)
- Wait on BOOKKEEP slots for clear onn free (Thomas)
- s/XE_MIGRATE_CLEAR_NON_DIRTY/XE_MIGRATE_CLEAR_FLAG_ON_FREE
- Do not requested clear memory in VRAM manager if BO as TT data (Auld)
Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
drivers/gpu/drm/xe/xe_bo.c | 48 ++++++++++++++++++++++++++++
drivers/gpu/drm/xe/xe_migrate.c | 31 ++++++++++++------
drivers/gpu/drm/xe/xe_migrate.h | 1 +
drivers/gpu/drm/xe/xe_res_cursor.h | 26 +++++++++++++++
drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 6 +++-
drivers/gpu/drm/xe/xe_ttm_vram_mgr.h | 6 ++++
6 files changed, 108 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 7a412121477e..900f67deef9d 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -1453,6 +1453,52 @@ static bool xe_ttm_bo_lock_in_destructor(struct ttm_buffer_object *ttm_bo)
return locked;
}
+static void xe_ttm_bo_release_clear(struct ttm_buffer_object *ttm_bo)
+{
+ struct xe_device *xe = ttm_to_xe_device(ttm_bo->bdev);
+ struct xe_bo *bo = ttm_to_xe_bo(ttm_bo);
+ struct dma_fence *fence;
+ int err, idx;
+
+ xe_bo_assert_held(ttm_to_xe_bo(ttm_bo));
+
+ if (ttm_bo->type != ttm_bo_type_device)
+ return;
+
+ if (xe_device_wedged(xe))
+ return;
+
+ if (!ttm_bo->resource || !mem_type_is_vram(ttm_bo->resource->mem_type))
+ return;
+
+ if (!drm_dev_enter(&xe->drm, &idx))
+ return;
+
+ if (!xe_pm_runtime_get_if_active(xe))
+ goto unbind;
+
+ err = dma_resv_reserve_fences(&ttm_bo->base._resv, 1);
+ if (err)
+ goto put_pm;
+
+ fence = xe_migrate_clear(mem_type_to_migrate(xe, ttm_bo->resource->mem_type),
+ ttm_bo->resource, &ttm_bo->base._resv, NULL,
+ bo->size, XE_MIGRATE_CLEAR_FLAG_FULL |
+ XE_MIGRATE_CLEAR_FLAG_ON_FREE, &bo->ccs_cleared);
+ if (XE_WARN_ON(IS_ERR(fence)))
+ goto put_pm;
+
+ xe_ttm_vram_mgr_resource_set_cleared(ttm_bo->resource);
+ dma_resv_add_fence(&ttm_bo->base._resv, fence,
+ DMA_RESV_USAGE_KERNEL);
+ dma_fence_put(fence);
+
+put_pm:
+ xe_pm_runtime_put(xe);
+unbind:
+ drm_dev_exit(idx);
+}
+
static void xe_ttm_bo_release_notify(struct ttm_buffer_object *ttm_bo)
{
struct dma_resv_iter cursor;
@@ -1497,6 +1543,8 @@ static void xe_ttm_bo_release_notify(struct ttm_buffer_object *ttm_bo)
}
dma_fence_put(replacement);
+ xe_ttm_bo_release_clear(ttm_bo);
+
dma_resv_unlock(ttm_bo->base.resv);
}
diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
index 18030f9613ae..7620f4eb8fb3 100644
--- a/drivers/gpu/drm/xe/xe_migrate.c
+++ b/drivers/gpu/drm/xe/xe_migrate.c
@@ -1067,7 +1067,7 @@ struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
struct xe_gt *gt = m->tile->primary_gt;
struct xe_device *xe = gt_to_xe(gt);
bool clear_only_system_ccs = false;
- struct dma_fence *fence = NULL;
+ struct dma_fence *fence = dma_fence_get_stub();
struct xe_res_cursor src_it;
struct ttm_resource *src = dst;
int err;
@@ -1078,10 +1078,13 @@ struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
if (!clear_bo_data && clear_ccs && !IS_DGFX(xe))
clear_only_system_ccs = true;
- if (!clear_vram)
+ if (!clear_vram) {
xe_res_first_sg(sgt, 0, size, &src_it);
- else
+ } else {
xe_res_first(src, 0, size, &src_it);
+ if (!(clear_flags & XE_MIGRATE_CLEAR_FLAG_ON_FREE))
+ size -= xe_res_next_dirty(&src_it);
+ }
while (size) {
u64 clear_L0_ofs;
@@ -1128,6 +1131,9 @@ struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
emit_pte(m, bb, clear_L0_pt, clear_vram, clear_only_system_ccs,
&src_it, clear_L0, dst);
+ if (clear_vram && !(clear_flags & XE_MIGRATE_CLEAR_FLAG_ON_FREE))
+ size -= xe_res_next_dirty(&src_it);
+
bb->cs[bb->len++] = MI_BATCH_BUFFER_END;
update_idx = bb->len;
@@ -1149,15 +1155,22 @@ struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
}
xe_sched_job_add_migrate_flush(job, flush_flags);
- if (!fence) {
+ if (fence == dma_fence_get_stub()) {
+ enum dma_resv_usage usage =
+ (clear_flags & XE_MIGRATE_CLEAR_FLAG_ON_FREE) ?
+ DMA_RESV_USAGE_BOOKKEEP : DMA_RESV_USAGE_KERNEL;
+
/*
- * There can't be anything userspace related at this
- * point, so we just need to respect any potential move
- * fences, which are always tracked as
+ * For initial clears, there can't be anything userspace
+ * related at this point, so we just need to respect any
+ * potential move fences, which are always tracked as
* DMA_RESV_USAGE_KERNEL.
+ *
+ * For clear on free need to respect all fences as
+ * memory could still be in use by the GPU which is
+ * tracked in DMA_RESV_USAGE_BOOKKEEP.
*/
- err = xe_sched_job_add_deps(job, resv,
- DMA_RESV_USAGE_KERNEL);
+ err = xe_sched_job_add_deps(job, resv, usage);
if (err)
goto err_job;
}
diff --git a/drivers/gpu/drm/xe/xe_migrate.h b/drivers/gpu/drm/xe/xe_migrate.h
index 04b3cd86ba90..104c61812ba1 100644
--- a/drivers/gpu/drm/xe/xe_migrate.h
+++ b/drivers/gpu/drm/xe/xe_migrate.h
@@ -120,6 +120,7 @@ int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo *bo,
#define XE_MIGRATE_CLEAR_FLAG_BO_DATA BIT(0)
#define XE_MIGRATE_CLEAR_FLAG_CCS_DATA BIT(1)
+#define XE_MIGRATE_CLEAR_FLAG_ON_FREE BIT(2)
#define XE_MIGRATE_CLEAR_FLAG_FULL (XE_MIGRATE_CLEAR_FLAG_BO_DATA | \
XE_MIGRATE_CLEAR_FLAG_CCS_DATA)
struct dma_fence *xe_migrate_clear(struct xe_migrate *m,
diff --git a/drivers/gpu/drm/xe/xe_res_cursor.h b/drivers/gpu/drm/xe/xe_res_cursor.h
index d1a403cfb628..630082e809ba 100644
--- a/drivers/gpu/drm/xe/xe_res_cursor.h
+++ b/drivers/gpu/drm/xe/xe_res_cursor.h
@@ -315,6 +315,32 @@ static inline void xe_res_next(struct xe_res_cursor *cur, u64 size)
}
}
+/**
+ * xe_res_next_dirty - advance the cursor to next dirty buddy block
+ *
+ * @cur: the cursor to advance
+ *
+ * Move the cursor until dirty buddy block is found.
+ *
+ * Return: Number of bytes cursor has been advanced
+ */
+static inline u64 xe_res_next_dirty(struct xe_res_cursor *cur)
+{
+ struct drm_buddy_block *block = cur->node;
+ u64 bytes = 0;
+
+ XE_WARN_ON(cur->mem_type != XE_PL_VRAM0 &&
+ cur->mem_type != XE_PL_VRAM1);
+
+ while (cur->remaining && drm_buddy_block_is_clear(block)) {
+ bytes += cur->size;
+ xe_res_next(cur, cur->size);
+ block = cur->node;
+ }
+
+ return bytes;
+}
+
/**
* xe_res_dma - return dma address of cursor at current position
*
diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
index 9e375a40aee9..838739e47815 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
@@ -84,6 +84,10 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
if (place->fpfn || lpfn != man->size >> PAGE_SHIFT)
vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
+ if (tbo->type == ttm_bo_type_device &&
+ !xe_bo_tt_has_data(ttm_to_xe_bo(tbo)))
+ vres->flags |= DRM_BUDDY_CLEAR_ALLOCATION;
+
if (WARN_ON(!vres->base.size)) {
err = -EINVAL;
goto error_fini;
@@ -187,7 +191,7 @@ static void xe_ttm_vram_mgr_del(struct ttm_resource_manager *man,
struct drm_buddy *mm = &mgr->mm;
mutex_lock(&mgr->lock);
- drm_buddy_free_list(mm, &vres->blocks, 0);
+ drm_buddy_free_list(mm, &vres->blocks, vres->flags);
mgr->visible_avail += vres->used_visible_size;
mutex_unlock(&mgr->lock);
diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
index cc76050e376d..dfc0e6890b3c 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
@@ -36,6 +36,12 @@ to_xe_ttm_vram_mgr_resource(struct ttm_resource *res)
return container_of(res, struct xe_ttm_vram_mgr_resource, base);
}
+static inline void
+xe_ttm_vram_mgr_resource_set_cleared(struct ttm_resource *res)
+{
+ to_xe_ttm_vram_mgr_resource(res)->flags |= DRM_BUDDY_CLEARED;
+}
+
static inline struct xe_ttm_vram_mgr *
to_xe_ttm_vram_mgr(struct ttm_resource_manager *man)
{
--
2.34.1
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