[Mesa-dev] [PATCH 1/5] winsys/amdgpu: always allow GTT placements on APUs

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/gallium/winsys/amdgpu/drm/amdgpu_bo.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
index 7740b46b7b9..22b5a73143d 100644
--- a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
+++ b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
@@ -402,28 +402,26 @@ static struct amdgpu_winsys_bo *amdgpu_create_bo(struct amdgpu_winsys *ws,
                           heap);
    }
    request.alloc_size = size;
    request.phys_alignment = alignment;
 
    if (initial_domain & RADEON_DOMAIN_VRAM)
       request.preferred_heap |= AMDGPU_GEM_DOMAIN_VRAM;
    if (initial_domain & RADEON_DOMAIN_GTT)
       request.preferred_heap |= AMDGPU_GEM_DOMAIN_GTT;
 
-   /* If VRAM is just stolen system memory, allow both VRAM and
-    * GTT, whichever has free space. If a buffer is evicted from
-    * VRAM to GTT, it will stay there.
-    *
-    * DRM 3.6.0 has good BO move throttling, so we can allow VRAM-only
-    * placements even with a low amount of stolen VRAM.
+   /* Since VRAM and GTT have almost the same performance on APUs, we could
+    * just set GTT. However, in order to decrease GTT(RAM) usage, which is
+    * shared with the OS, allow VRAM placements too. The idea is not to use
+    * VRAM usefully, but to use it so that it's not unused and wasted.
     */
-   if (!ws->info.has_dedicated_vram && ws->info.drm_minor < 6)
+   if (!ws->info.has_dedicated_vram)
       request.preferred_heap |= AMDGPU_GEM_DOMAIN_GTT;
 
    if (flags & RADEON_FLAG_NO_CPU_ACCESS)
       request.flags |= AMDGPU_GEM_CREATE_NO_CPU_ACCESS;
    if (flags & RADEON_FLAG_GTT_WC)
       request.flags |= AMDGPU_GEM_CREATE_CPU_GTT_USWC;
    if (flags & RADEON_FLAG_NO_INTERPROCESS_SHARING &&
        ws->info.has_local_buffers)
       request.flags |= AMDGPU_GEM_CREATE_VM_ALWAYS_VALID;
 
-- 
2.15.1