[Intel-xe] [PATCH v3 2/4] drm/xe/bo: Avoid creating a system resource when allocating a fresh VRAM bo

[Matthew Auld]

On Mon, 26 Jun 2023 at 19:18, Thomas Hellström
<thomas.hellstrom at linux.intel.com> wrote:
>
> When creating a new bo, on the first move the bo->resource is typically
> NULL. Our move callback rejected that instructing TTM to create a system
> resource. In addition a struct ttm_tt with a page-vector was created,
> although not populated with pages. Similarly when the clearing of VRAM
> was complete, the system resource was put on a ghost object and freed
> using the TTM delayed destroy mechanism.
>
> This is a lot of pointless work. So avoid creating the system resource and
> instead change the code to cope with a NULL bo->resource.
>
> v2:
> - Add some code comments (Matthew Brost)
> v3:
> - Fix a dereference of old_mem which might be NULL.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>