On Thu, Nov 18, 2021 at 10:26:16AM -0500, Josef Bacik wrote:

+ */
+static inline u64 get_max_extent_size(struct btrfs_free_space *entry)
+{
+	if (entry->bitmap && entry->max_extent_size)
+		return entry->max_extent_size;
+	return entry->bytes;
+}
+
+/*
+ * This is indexed in reverse of what we generally do for rb-tree's, the largest
+ * chunks are left most and the smallest are rightmost.  This is so that we can
+ * take advantage of the cached property of the cached rb-tree and simply get
+ * the largest free space chunk right away.
+ */
+static void tree_insert_bytes(struct btrfs_free_space_ctl *ctl,
+			      struct btrfs_free_space *info)
+{
+	struct rb_root_cached *root = &ctl->free_space_bytes;
+	struct rb_node **p = &root->rb_root.rb_node;

Please don't use single letter variables, other than 'i' for indexing.
For tree nodes I've been renaming it to 'node' in any new code.

+	struct rb_node *parent_node = NULL;
+	struct btrfs_free_space *tmp;
+	bool leftmost = true;
+
+	while (*p) {
+		parent_node = *p;
+		tmp = rb_entry(parent_node, struct btrfs_free_space,
+			       bytes_index);
+		if (get_max_extent_size(info) < get_max_extent_size(tmp)) {
+			p = &(*p)->rb_right;
+			leftmost = false;
+		} else {
+			p = &(*p)->rb_left;
+		}
+	}
+
+	rb_link_node(&info->bytes_index, parent_node, p);
+	rb_insert_color_cached(&info->bytes_index, root, leftmost);
+}
+
 /*
  * searches the tree for the given offset.
  *