Re: [RFC PATCH V7 05/10] drm/xe: Extend BO purge to handle vram pages as well

[Matthew Brost <matthew.brost@intel.com>]

On Thu, Apr 16, 2026 at 01:19:54PM +0530, Tejas Upadhyay wrote:
> Recent driver update introduce support for purgeable buffer
> objects (BOs), extending the API to include VRAM pages to
> better manage memory pressure and enable memory offlining.
> 
> Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_bo.c | 5 +----
>  drivers/gpu/drm/xe/xe_bo.h | 1 +
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index 5ce60d161e09..04d3b25c7c8e 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -903,7 +903,7 @@ void xe_bo_set_purgeable_state(struct xe_bo *bo,
>   *
>   * Return: 0 on success, negative error code on failure
>   */
> -static int xe_ttm_bo_purge(struct ttm_buffer_object *ttm_bo, struct ttm_operation_ctx *ctx)
> +int xe_ttm_bo_purge(struct ttm_buffer_object *ttm_bo, struct ttm_operation_ctx *ctx)
>  {
>  	struct xe_bo *bo = ttm_to_xe_bo(ttm_bo);
>  	struct ttm_placement place = {};
> @@ -911,9 +911,6 @@ static int xe_ttm_bo_purge(struct ttm_buffer_object *ttm_bo, struct ttm_operatio
>  
>  	xe_bo_assert_held(bo);
>  
> -	if (!ttm_bo->ttm)
> -		return 0;
> -

I think blindly deleting this is fine but I'd run this by Arvind to make
sure in normal purge flow this won't do anything bad but afiak in normal
purge flows ttm_bo->ttm will never be NULL.

If not then adjust the existing call...

@@ -978,7 +978,8 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict,
         * The move_notify callback will handle invalidation asynchronously.
         */
        if (evict && xe_bo_madv_is_dontneed(bo)) {
-               ret = xe_ttm_bo_purge(ttm_bo, ctx);
+               if (ttm_bo->ttm)
+                       ret = xe_ttm_bo_purge(ttm_bo, ctx);
                if (ret)
                        return ret;

Matt 

>  	if (!xe_bo_madv_is_dontneed(bo))
>  		return 0;
>  
> diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
> index 68dea7d25a6b..9f55b3589caf 100644
> --- a/drivers/gpu/drm/xe/xe_bo.h
> +++ b/drivers/gpu/drm/xe/xe_bo.h
> @@ -500,6 +500,7 @@ struct xe_bo_shrink_flags {
>  long xe_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo,
>  		  const struct xe_bo_shrink_flags flags,
>  		  unsigned long *scanned);
> +int xe_ttm_bo_purge(struct ttm_buffer_object *ttm_bo, struct ttm_operation_ctx *ctx);
>  
>  /**
>   * xe_bo_is_mem_type - Whether the bo currently resides in the given
> -- 
> 2.52.0
>