[RFC PATCH 03/18] drm/ttm: Implement BO eviction tracking

[Friedrich Vock <friedrich.vock@xxxxxx>]

For each buffer object, remember evictions and try undoing them if
memory pressure gets lower again.

Signed-off-by: Friedrich Vock <friedrich.vock@xxxxxx>
---
 drivers/gpu/drm/ttm/ttm_bo.c      | 28 +++++++++++++++++++++++++++-
 drivers/gpu/drm/ttm/ttm_bo_util.c |  3 +++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 3968b17453569..9a0efbf79316c 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -178,6 +178,12 @@ static void ttm_bo_cleanup_memtype_use(struct ttm_buffer_object *bo)
 {
 	if (bo->bdev->funcs->delete_mem_notify)
 		bo->bdev->funcs->delete_mem_notify(bo);
+	if (bo->evicted_type != TTM_NUM_MEM_TYPES) {
+		spin_lock(&bo->bdev->unevict_lock);
+		list_del_init(&bo->evicted);
+		man->evicted_bytes -= bo->base.size;
+		spin_unlock(&bo->bdev->unevict_lock);
+	}

 	ttm_bo_tt_destroy(bo);
 	ttm_resource_free(bo, &bo->resource);
@@ -429,7 +435,9 @@ static int ttm_bo_bounce_temp_buffer(struct ttm_buffer_object *bo,
 static int ttm_bo_evict(struct ttm_buffer_object *bo,
 			struct ttm_operation_ctx *ctx)
 {
+	int evicted_type = bo->resource->mem_type;
 	struct ttm_device *bdev = bo->bdev;
+	struct ttm_resource_manager *man;
 	struct ttm_resource *evict_mem;
 	struct ttm_placement placement;
 	struct ttm_place hop;
@@ -438,6 +446,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo,
 	memset(&hop, 0, sizeof(hop));

 	dma_resv_assert_held(bo->base.resv);
+	man = ttm_manager_type(bdev, evicted_type);

 	placement.num_placement = 0;
 	placement.num_busy_placement = 0;
@@ -477,6 +486,14 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo,
 		ttm_resource_free(bo, &evict_mem);
 		if (ret != -ERESTARTSYS && ret != -EINTR)
 			pr_err("Buffer eviction failed\n");
+	} else if (bo->evicted_type == TTM_NUM_MEM_TYPES &&
+		   bo->bdev->funcs->uneviction_valuable &&
+		   bo->bdev->funcs->uneviction_valuable(bo)) {
+		bo->evicted_type = evicted_type;
+		spin_lock(&bo->bdev->unevict_lock);
+		list_add_tail(&bo->evicted, &man->evicted);
+		man->evicted_bytes += bo->base.size;
+		spin_unlock(&bo->bdev->unevict_lock);
 	}
 out:
 	return ret;
@@ -845,6 +862,7 @@ static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
 			      struct ttm_placement *placement,
 			      struct ttm_operation_ctx *ctx)
 {
+	struct ttm_resource_manager *man;
 	struct ttm_resource *mem;
 	struct ttm_place hop;
 	int ret;
@@ -873,8 +891,16 @@ static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
 		goto bounce;
 	}
 out:
-	if (ret)
+	if (ret) {
 		ttm_resource_free(bo, &mem);
+	} else if (bo->evicted_type != TTM_NUM_MEM_TYPES) {
+		man = ttm_manager_type(bo->bdev, bo->evicted_type);
+		spin_lock(&bo->bdev->unevict_lock);
+		list_del_init(&bo->evicted);
+		man->evicted_bytes -= bo->base.size;
+		spin_unlock(&bo->bdev->unevict_lock);
+		bo->evicted_type = TTM_NUM_MEM_TYPES;
+	}
 	return ret;
 }

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index fd9fd3d15101c..119291c5ed85e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -262,6 +262,9 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 		fbo->base.bulk_move = NULL;
 	}

+	INIT_LIST_HEAD(&fbo->base.evicted);
+	fbo->base.evicted_type = TTM_NUM_MEM_TYPES;
+
 	ret = dma_resv_reserve_fences(&fbo->base.base._resv, 1);
 	if (ret) {
 		kfree(fbo);
--
2.44.0