Commit 75521e8b authored by Thomas Hellström's avatar Thomas Hellström
Browse files

drm/xe: Perform dma_map when moving system buffer objects to TT 



Currently we dma_map on ttm_tt population and dma_unmap when
the pages are released in ttm_tt unpopulate.

Strictly, the dma_map is not needed until the bo is moved to the
XE_PL_TT placement, so perform the dma_mapping on such moves
instead, and remove the dma_mappig when moving to XE_PL_SYSTEM.

This is desired for the upcoming shrinker series where shrinking
of a ttm_tt might fail. That would lead to an odd construct where
we first dma_unmap, then shrink and if shrinking fails dma_map
again. If dma_mapping instead is performed on move like this,
shrinking does not need to care at all about dma mapping.

Finally, where a ttm_tt is destroyed while bound to a different
memory type than XE_PL_SYSTEM, we keep the dma_unmap in
unpopulate().

v2:
- Don't accidently unmap the dma-buf's sgtable.

Signed-off-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502183251.10170-1-thomas.hellstrom@linux.intel.com
parent 8ad0e181

drivers/gpu/drm/xe/xe_bo.c

+30 −17
Original line number Diff line number Diff line
@@ -302,6 +302,18 @@ static int xe_tt_map_sg(struct ttm_tt *tt) 
	return 0;

}



static void xe_tt_unmap_sg(struct ttm_tt *tt)

{

	struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);



	if (xe_tt->sg) {

		dma_unmap_sgtable(xe_tt->dev, xe_tt->sg,

				  DMA_BIDIRECTIONAL, 0);

		sg_free_table(xe_tt->sg);

		xe_tt->sg = NULL;

	}

}



struct sg_table *xe_bo_sg(struct xe_bo *bo)

{

	struct ttm_tt *tt = bo->ttm.ttm;
@@ -377,27 +389,15 @@ static int xe_ttm_tt_populate(struct ttm_device *ttm_dev, struct ttm_tt *tt, 
	if (err)

		return err;



	/* A follow up may move this xe_bo_move when BO is moved to XE_PL_TT */

	err = xe_tt_map_sg(tt);

	if (err)

		ttm_pool_free(&ttm_dev->pool, tt);



	return err;

}



static void xe_ttm_tt_unpopulate(struct ttm_device *ttm_dev, struct ttm_tt *tt)

{

	struct xe_ttm_tt *xe_tt = container_of(tt, struct xe_ttm_tt, ttm);



	if (tt->page_flags & TTM_TT_FLAG_EXTERNAL)

		return;



	if (xe_tt->sg) {

		dma_unmap_sgtable(xe_tt->dev, xe_tt->sg,

				  DMA_BIDIRECTIONAL, 0);

		sg_free_table(xe_tt->sg);

		xe_tt->sg = NULL;

	}

	xe_tt_unmap_sg(tt);



	return ttm_pool_free(&ttm_dev->pool, tt);

}
@@ -628,17 +628,21 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, 
	bool handle_system_ccs = (!IS_DGFX(xe) && xe_bo_needs_ccs_pages(bo) &&

				  ttm && ttm_tt_is_populated(ttm)) ? true : false;

	int ret = 0;



	/* Bo creation path, moving to system or TT. */

	if ((!old_mem && ttm) && !handle_system_ccs) {

		if (new_mem->mem_type == XE_PL_TT)

			ret = xe_tt_map_sg(ttm);

		if (!ret)

			ttm_bo_move_null(ttm_bo, new_mem);

		return 0;

		goto out;

	}



	if (ttm_bo->type == ttm_bo_type_sg) {

		ret = xe_bo_move_notify(bo, ctx);

		if (!ret)

			ret = xe_bo_move_dmabuf(ttm_bo, new_mem);

		goto out;

		return ret;

	}



	tt_has_data = ttm && (ttm_tt_is_populated(ttm) ||
@@ -650,6 +654,12 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, 
	needs_clear = (ttm && ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC) ||

		(!ttm && ttm_bo->type == ttm_bo_type_device);



	if (new_mem->mem_type == XE_PL_TT) {

		ret = xe_tt_map_sg(ttm);

		if (ret)

			goto out;

	}



	if ((move_lacks_source && !needs_clear)) {

		ttm_bo_move_null(ttm_bo, new_mem);

		goto out;
@@ -786,8 +796,11 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, 
	xe_pm_runtime_put(xe);



out:

	return ret;

	if ((!ttm_bo->resource || ttm_bo->resource->mem_type == XE_PL_SYSTEM) &&

	    ttm_bo->ttm)

		xe_tt_unmap_sg(ttm_bo->ttm);



	return ret;

}



/**