[Intel-xe] [PATCH 1/2] drm/xe/bo: further limit where CCS pages are needed

[Nirmoy Das]

On 5/25/2023 1:45 PM, Matthew Auld wrote:
> No need to allocate extra pages for this if we know flat-ccs AUX state
> is not even possible, like for normal system memory objects.
>
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das at intel.com>
> ---
>   drivers/gpu/drm/xe/xe_bo.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
> index c82e995df779..f994dbed634b 100644
> --- a/drivers/gpu/drm/xe/xe_bo.c
> +++ b/drivers/gpu/drm/xe/xe_bo.c
> @@ -283,6 +283,7 @@ static struct ttm_tt *xe_ttm_tt_create(struct ttm_buffer_object *ttm_bo,
>   	struct xe_bo *bo = ttm_to_xe_bo(ttm_bo);
>   	struct xe_device *xe = xe_bo_device(bo);
>   	struct xe_ttm_tt *tt;
> +	unsigned long extra_pages;
>   	int err;
>   
>   	tt = kzalloc(sizeof(*tt), GFP_KERNEL);
> @@ -291,12 +292,15 @@ static struct ttm_tt *xe_ttm_tt_create(struct ttm_buffer_object *ttm_bo,
>   
>   	tt->dev = xe->drm.dev;
>   
> +	extra_pages = 0;
> +	if (xe_bo_needs_ccs_pages(bo))
> +		extra_pages = DIV_ROUND_UP(xe_device_ccs_bytes(xe, bo->size),
> +					   PAGE_SIZE);
> +
>   	/* TODO: Select caching mode */
>   	err = ttm_tt_init(&tt->ttm, &bo->ttm, page_flags,
>   			  bo->flags & XE_BO_SCANOUT_BIT ? ttm_write_combined : ttm_cached,
> -			  DIV_ROUND_UP(xe_device_ccs_bytes(xe_bo_device(bo),
> -							   bo->ttm.base.size),
> -				       PAGE_SIZE));
> +			  extra_pages);
>   	if (err) {
>   		kfree(tt);
>   		return NULL;