drm/ttm: simplify memory accounting for ttm user v2

Provide helper function to compute the kernel memory size needed
for each buffer object. Move all the accounting inside ttm, simplifying
driver and avoiding code duplication accross them.

v2 fix accounting of ghost object, one would have thought that i
   would have run into the issue since a longtime but it seems
   ghost object are rare when you have plenty of vram ;)

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -93,6 +93,7 @@ nouveau_bo_new(struct drm_device *dev, int size, int align,
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct nouveau_bo *nvbo;
+	size_t acc_size;
 	int ret;
 
 	nvbo = kzalloc(sizeof(struct nouveau_bo), GFP_KERNEL);
@@ -115,9 +116,12 @@ nouveau_bo_new(struct drm_device *dev, int size, int align,
 	nvbo->bo.mem.num_pages = size >> PAGE_SHIFT;
 	nouveau_bo_placement_set(nvbo, flags, 0);
 
+	acc_size = ttm_bo_dma_acc_size(&dev_priv->ttm.bdev, size,
+				       sizeof(struct nouveau_bo));
+
 	ret = ttm_bo_init(&dev_priv->ttm.bdev, &nvbo->bo, size,
 			  ttm_bo_type_device, &nvbo->placement,
-			  align >> PAGE_SHIFT, 0, false, NULL, size,
+			  align >> PAGE_SHIFT, 0, false, NULL, acc_size,
 			  nouveau_bo_del_ttm);
 	if (ret) {
 		/* ttm will call nouveau_bo_del_ttm if it fails.. */

drivers/gpu/drm/radeon/radeon_object.c

@@ -95,6 +95,7 @@ int radeon_bo_create(struct radeon_device *rdev,
 	enum ttm_bo_type type;
 	unsigned long page_align = roundup(byte_align, PAGE_SIZE) >> PAGE_SHIFT;
 	unsigned long max_size = 0;
+	size_t acc_size;
 	int r;
 
 	size = ALIGN(size, PAGE_SIZE);
@@ -117,6 +118,9 @@ int radeon_bo_create(struct radeon_device *rdev,
 		return -ENOMEM;
 	}
 
+	acc_size = ttm_bo_dma_acc_size(&rdev->mman.bdev, size,
+				       sizeof(struct radeon_bo));
+
 retry:
 	bo = kzalloc(sizeof(struct radeon_bo), GFP_KERNEL);
 	if (bo == NULL)
@@ -134,8 +138,8 @@ int radeon_bo_create(struct radeon_device *rdev,
 	/* Kernel allocation are uninterruptible */
 	mutex_lock(&rdev->vram_mutex);
 	r = ttm_bo_init(&rdev->mman.bdev, &bo->tbo, size, type,
-			&bo->placement, page_align, 0, !kernel, NULL, size,
-			&radeon_ttm_bo_destroy);
+			&bo->placement, page_align, 0, !kernel, NULL,
+			acc_size, &radeon_ttm_bo_destroy);
 	mutex_unlock(&rdev->vram_mutex);
 	if (unlikely(r != 0)) {
 		if (r != -ERESTARTSYS) {

drivers/gpu/drm/ttm/ttm_bo.c

@@ -137,6 +137,7 @@ static void ttm_bo_release_list(struct kref *list_kref)
 	struct ttm_buffer_object *bo =
 	    container_of(list_kref, struct ttm_buffer_object, list_kref);
 	struct ttm_bo_device *bdev = bo->bdev;
+	size_t acc_size = bo->acc_size;
 
 	BUG_ON(atomic_read(&bo->list_kref.refcount));
 	BUG_ON(atomic_read(&bo->kref.refcount));
@@ -152,9 +153,9 @@ static void ttm_bo_release_list(struct kref *list_kref)
 	if (bo->destroy)
 		bo->destroy(bo);
 	else {
-		ttm_mem_global_free(bdev->glob->mem_glob, bo->acc_size);
 		kfree(bo);
 	}
+	ttm_mem_global_free(bdev->glob->mem_glob, acc_size);
 }
 
 int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible)
@@ -1157,6 +1158,17 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 {
 	int ret = 0;
 	unsigned long num_pages;
+	struct ttm_mem_global *mem_glob = bdev->glob->mem_glob;
+
+	ret = ttm_mem_global_alloc(mem_glob, acc_size, false, false);
+	if (ret) {
+		printk(KERN_ERR TTM_PFX "Out of kernel memory.\n");
+		if (destroy)
+			(*destroy)(bo);
+		else
+			kfree(bo);
+		return -ENOMEM;
+	}
 
 	size += buffer_start & ~PAGE_MASK;
 	num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -1227,14 +1239,34 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 }
 EXPORT_SYMBOL(ttm_bo_init);
 
-static inline size_t ttm_bo_size(struct ttm_bo_global *glob,
-				 unsigned long num_pages)
+size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
+		       unsigned long bo_size,
+		       unsigned struct_size)
 {
-	size_t page_array_size = (num_pages * sizeof(void *) + PAGE_SIZE - 1) &
-	    PAGE_MASK;
+	unsigned npages = (PAGE_ALIGN(bo_size)) >> PAGE_SHIFT;
+	size_t size = 0;
 
-	return glob->ttm_bo_size + 2 * page_array_size;
+	size += ttm_round_pot(struct_size);
+	size += PAGE_ALIGN(npages * sizeof(void *));
+	size += ttm_round_pot(sizeof(struct ttm_tt));
+	return size;
 }
+EXPORT_SYMBOL(ttm_bo_acc_size);
+
+size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
+			   unsigned long bo_size,
+			   unsigned struct_size)
+{
+	unsigned npages = (PAGE_ALIGN(bo_size)) >> PAGE_SHIFT;
+	size_t size = 0;
+
+	size += ttm_round_pot(struct_size);
+	size += PAGE_ALIGN(npages * sizeof(void *));
+	size += PAGE_ALIGN(npages * sizeof(dma_addr_t));
+	size += ttm_round_pot(sizeof(struct ttm_dma_tt));
+	return size;
+}
+EXPORT_SYMBOL(ttm_bo_dma_acc_size);
 
 int ttm_bo_create(struct ttm_bo_device *bdev,
 			unsigned long size,
@@ -1248,10 +1280,10 @@ int ttm_bo_create(struct ttm_bo_device *bdev,
 {
 	struct ttm_buffer_object *bo;
 	struct ttm_mem_global *mem_glob = bdev->glob->mem_glob;
+	size_t acc_size;
 	int ret;
 
-	size_t acc_size =
-	    ttm_bo_size(bdev->glob, (size + PAGE_SIZE - 1) >> PAGE_SHIFT);
+	acc_size = ttm_bo_acc_size(bdev, size, sizeof(struct ttm_buffer_object));
 	ret = ttm_mem_global_alloc(mem_glob, acc_size, false, false);
 	if (unlikely(ret != 0))
 		return ret;
@@ -1437,10 +1469,6 @@ int ttm_bo_global_init(struct drm_global_reference *ref)
 		goto out_no_shrink;
 	}
 
-	glob->ttm_bo_extra_size = ttm_round_pot(sizeof(struct ttm_tt));
-	glob->ttm_bo_size = glob->ttm_bo_extra_size +
-		ttm_round_pot(sizeof(struct ttm_buffer_object));
-
 	atomic_set(&glob->bo_count, 0);
 
 	ret = kobject_init_and_add(

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -445,6 +445,7 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 	kref_init(&fbo->list_kref);
 	kref_init(&fbo->kref);
 	fbo->destroy = &ttm_transfered_destroy;
+	fbo->acc_size = 0;
 
 	*new_obj = fbo;
 	return 0;

drivers/gpu/drm/vmwgfx/vmwgfx_resource.c

@@ -1517,29 +1517,10 @@ int vmw_surface_check(struct vmw_private *dev_priv,
 /**
  * Buffer management.
  */
-
-static size_t vmw_dmabuf_acc_size(struct ttm_bo_global *glob,
-				  unsigned long num_pages)
-{
-	static size_t bo_user_size = ~0;
-
-	size_t page_array_size =
-	    (num_pages * sizeof(void *) + PAGE_SIZE - 1) & PAGE_MASK;
-
-	if (unlikely(bo_user_size == ~0)) {
-		bo_user_size = glob->ttm_bo_extra_size +
-		    ttm_round_pot(sizeof(struct vmw_dma_buffer));
-	}
-
-	return bo_user_size + page_array_size;
-}
-
 void vmw_dmabuf_bo_free(struct ttm_buffer_object *bo)
 {
 	struct vmw_dma_buffer *vmw_bo = vmw_dma_buffer(bo);
-	struct ttm_bo_global *glob = bo->glob;
 
-	ttm_mem_global_free(glob->mem_glob, bo->acc_size);
 	kfree(vmw_bo);
 }
 
@@ -1550,24 +1531,12 @@ int vmw_dmabuf_init(struct vmw_private *dev_priv,
 		    void (*bo_free) (struct ttm_buffer_object *bo))
 {
 	struct ttm_bo_device *bdev = &dev_priv->bdev;
-	struct ttm_mem_global *mem_glob = bdev->glob->mem_glob;
 	size_t acc_size;
 	int ret;
 
 	BUG_ON(!bo_free);
 
-	acc_size =
-	    vmw_dmabuf_acc_size(bdev->glob,
-				(size + PAGE_SIZE - 1) >> PAGE_SHIFT);
-
-	ret = ttm_mem_global_alloc(mem_glob, acc_size, false, false);
-	if (unlikely(ret != 0)) {
-		/* we must free the bo here as
-		 * ttm_buffer_object_init does so as well */
-		bo_free(&vmw_bo->base);
-		return ret;
-	}
-
+	acc_size = ttm_bo_acc_size(bdev, size, sizeof(struct vmw_dma_buffer));
 	memset(vmw_bo, 0, sizeof(*vmw_bo));
 
 	INIT_LIST_HEAD(&vmw_bo->validate_list);
@@ -1582,9 +1551,7 @@ int vmw_dmabuf_init(struct vmw_private *dev_priv,
 static void vmw_user_dmabuf_destroy(struct ttm_buffer_object *bo)
 {
 	struct vmw_user_dma_buffer *vmw_user_bo = vmw_user_dma_buffer(bo);
-	struct ttm_bo_global *glob = bo->glob;
 
-	ttm_mem_global_free(glob->mem_glob, bo->acc_size);
 	kfree(vmw_user_bo);
 }
 

include/drm/ttm/ttm_bo_api.h

@@ -429,9 +429,9 @@ extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
  * -EBUSY if the buffer is busy and no_wait is true.
  * -ERESTARTSYS if interrupted by a signal.
  */
-
 extern int
 ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
+
 /**
  * ttm_bo_synccpu_write_release:
  *
@@ -441,6 +441,22 @@ ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
  */
 extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
 
+/**
+ * ttm_bo_acc_size
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @bo_size: size of the buffer object in byte.
+ * @struct_size: size of the structure holding buffer object datas
+ *
+ * Returns size to account for a buffer object
+ */
+size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
+		       unsigned long bo_size,
+		       unsigned struct_size);
+size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
+			   unsigned long bo_size,
+			   unsigned struct_size);
+
 /**
  * ttm_bo_init
  *
@@ -488,6 +504,7 @@ extern int ttm_bo_init(struct ttm_bo_device *bdev,
 			struct file *persistent_swap_storage,
 			size_t acc_size,
 			void (*destroy) (struct ttm_buffer_object *));
+
 /**
  * ttm_bo_synccpu_object_init
  *

include/drm/ttm/ttm_bo_driver.h

@@ -469,9 +469,6 @@ struct ttm_bo_global_ref {
  * @dummy_read_page: Pointer to a dummy page used for mapping requests
  * of unpopulated pages.
  * @shrink: A shrink callback object used for buffer object swap.
- * @ttm_bo_extra_size: Extra size (sizeof(struct ttm_buffer_object) excluded)
- * used by a buffer object. This is excluding page arrays and backing pages.
- * @ttm_bo_size: This is @ttm_bo_extra_size + sizeof(struct ttm_buffer_object).
  * @device_list_mutex: Mutex protecting the device list.
  * This mutex is held while traversing the device list for pm options.
  * @lru_lock: Spinlock protecting the bo subsystem lru lists.
@@ -489,8 +486,6 @@ struct ttm_bo_global {
 	struct ttm_mem_global *mem_glob;
 	struct page *dummy_read_page;
 	struct ttm_mem_shrink shrink;
-	size_t ttm_bo_extra_size;
-	size_t ttm_bo_size;
 	struct mutex device_list_mutex;
 	spinlock_t lru_lock;