drm/amdgpu: immediately use GTT for new allocations

Only use GTT as a fallback if we already have a backing store. This
prevents evictions when an application constantly allocates and frees new
memory.

Partially fixes
https://gitlab.freedesktop.org/drm/amd/-/issues/3844#note_2833985.

Signed-off-by: Christian König <[email protected]>
Fixes: 216c128 ("drm/amdgpu: use GTT only as fallback for VRAM|GTT")
Acked-by: Alex Deucher <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Cc: [email protected]

Author: ChristianKoenigAMD

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

@@ -163,8 +163,8 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		 * When GTT is just an alternative to VRAM make sure that we
 		 * only use it as fallback and still try to fill up VRAM first.
 		 */
-		if (domain & abo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM &&
-		    !(adev->flags & AMD_IS_APU))
+		if (abo->tbo.resource && !(adev->flags & AMD_IS_APU) &&
+		    domain & abo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM)
 			places[c].flags |= TTM_PL_FLAG_FALLBACK;
 		c++;
 	}