[PATCH 1/2] drm/ttm: Don't evict SG BOs

[Christian König]

Am 28.04.21 um 07:33 schrieb Felix Kuehling:
> SG BOs do not occupy space that is managed by TTM. So do not evict them.
>
> This fixes unexpected evictions of KFD's userptr BOs. KFD only expects
> userptr "evictions" in the form of MMU notifiers.

NAK, SG BOs also account for the memory the GPU can currently access.

We can ignore them for the allocated memory, but not for the GTT domain.

Christian.

>
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
> ---
>   drivers/gpu/drm/ttm/ttm_bo.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index de1ec838cf8b..0b953654fdbf 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -655,6 +655,10 @@ int ttm_mem_evict_first(struct ttm_device *bdev,
>   		list_for_each_entry(bo, &man->lru[i], lru) {
>   			bool busy;
>   
> +			/* Don't evict SG BOs */
> +			if (bo->ttm && bo->ttm->sg)
> +				continue;
> +
>   			if (!ttm_bo_evict_swapout_allowable(bo, ctx, &locked,
>   							    &busy)) {
>   				if (busy && !busy_bo && ticket !=