[PATCH 3/3] drm/amdgpu: Try evicting from CPU visible to invisible VRAM first

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

In exchange, move BOs with the AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED
flag set to CPU visible VRAM with more force.

For other BOs, this gives another chance to stay in VRAM if they
happened to lie in the CPU visible part and another BO needs to go
there.

This should allow BOs to stay in VRAM longer in some cases.

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 19 ++++++++++++++-----
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 27 +++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 41ee353b22c8..d45c2325c61a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -963,11 +963,20 @@ int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
 					 AMDGPU_GEM_DOMAIN_GTT);
 	abo->placements[0].lpfn = adev->mc.visible_vram_size >> PAGE_SHIFT;
 
-	/* Only set GTT as busy placement; if there is no space in CPU visible
-	 * VRAM, move this BO to GTT instead of evicting other BOs
-	 */
-	abo->placement.busy_placement = &abo->placements[1];
-	abo->placement.num_busy_placement = 1;
+	if (abo->flags & AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED) {
+		/* Only set VRAM as normal placement; if there is no space in
+		 * CPU visible VRAM, evict other BOs, only fall back to GTT as
+		 * last resort
+		 */
+		abo->placement.num_placement = 1;
+	} else {
+		/* Only set GTT as busy placement; if there is no space in CPU
+		 * visible VRAM, move this BO to GTT instead of evicting other
+		 * BOs
+		 */
+		abo->placement.busy_placement = &abo->placements[1];
+		abo->placement.num_busy_placement = 1;
+	}
 
 	return ttm_bo_validate(bo, &abo->placement, false, false);
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 57789b860768..d5ed85026542 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -206,7 +206,34 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
 		    adev->mman.buffer_funcs_ring &&
 		    adev->mman.buffer_funcs_ring->ready == false) {
 			amdgpu_ttm_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_CPU);
+		} else if (adev->mc.visible_vram_size < adev->mc.real_vram_size) {
+			unsigned fpfn = adev->mc.visible_vram_size >> PAGE_SHIFT;
+			struct drm_mm_node *node = bo->mem.mm_node;
+			unsigned long pages_left;
+
+			for (pages_left = bo->mem.num_pages;
+			     pages_left;
+			     pages_left -= node->size, node++) {
+				if (node->start < fpfn)
+					break;
+			}
+
+			if (!pages_left)
+				goto gtt;
+
+			/* Try evicting to the CPU inaccessible part of VRAM
+			 * first, but only set GTT as busy placement, so this
+			 * BO will be evicted to GTT rather than causing other
+			 * BOs to be evicted from VRAM
+			 */
+			amdgpu_ttm_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_VRAM |
+							 AMDGPU_GEM_DOMAIN_GTT);
+			abo->placements[0].fpfn = fpfn;
+			abo->placements[0].lpfn = 0;
+			abo->placement.busy_placement = &abo->placements[1];
+			abo->placement.num_busy_placement = 1;
 		} else {
+gtt:
 			amdgpu_ttm_placement_from_domain(abo, AMDGPU_GEM_DOMAIN_GTT);
 			/* Set an upper limit to force directly allocating
 			 * address space for the BO.
-- 
2.11.0