[PATCH v3 3/4] drm/xe: Add xe_bo_tt_has_data helper

[Matthew Auld]

On 23/06/2025 16:19, Matthew Brost wrote:
> Add xe_bo_tt_has_data helper which determines if a BO has TT data (i.e.,
> a BO has SRAM or swap backing store).
> 
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
>   drivers/gpu/drm/xe/xe_bo.c | 21 ++++++++++++++++++---
>   drivers/gpu/drm/xe/xe_bo.h |  2 ++
>   2 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index c93381fa4858..7a412121477e 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -766,6 +766,23 @@ static int xe_bo_move_notify(struct xe_bo *bo,
>   	return 0;
>   }
>   
> +/**
> + * xe_bo_tt_has_data() - Xe BO has TT data (i.e., Xe BO has SRAM or swap backing
> + * store)
> + *
> + * Helper to determine if a BO has TT data. Useful to determine if copies or
> + * clears are needed on BO when it is moving.
> + *
> + * Return: True if a BO has TT data, False otherwise
> + */
> +bool xe_bo_tt_has_data(struct xe_bo *bo)
> +{

Maybe add an assert-locked for the bo? I'm pretty sure caller needs the 
lock to check such state?

Reviewed-by: Matthew Auld <matthew.auld at intel.com>


> +	struct ttm_tt *ttm = bo->ttm.ttm;
> +
> +	return ttm && (ttm_tt_is_populated(ttm) ||
> +		       (ttm->page_flags & TTM_TT_FLAG_SWAPPED));
> +}
> +
>   static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
>   		      struct ttm_operation_ctx *ctx,
>   		      struct ttm_resource *new_mem,
> @@ -801,9 +818,7 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
>   		return ret;
>   	}
>   
> -	tt_has_data = ttm && (ttm_tt_is_populated(ttm) ||
> -			      (ttm->page_flags & TTM_TT_FLAG_SWAPPED));
> -
> +	tt_has_data = xe_bo_tt_has_data(bo);
>   	move_lacks_source = !old_mem || (handle_system_ccs ? (!bo->ccs_cleared) :
>   					 (!mem_type_is_vram(old_mem_type) && !tt_has_data));
>   
> diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
> index 02ada1fb8a23..150e98ce6fac 100644
> --- a/drivers/gpu/drm/xe/xe_bo.h
> +++ b/drivers/gpu/drm/xe/xe_bo.h
> @@ -374,6 +374,8 @@ void xe_bo_dev_fini(struct xe_bo_dev *bo_device);
>   
>   struct sg_table *xe_bo_sg(struct xe_bo *bo);
>   
> +bool xe_bo_tt_has_data(struct xe_bo *bo);
> +
>   /*
>    * xe_sg_segment_size() - Provides upper limit for sg segment size.
>    * @dev: device pointer