rb_insert_node
int rb_insert_node(struct rbtree __arena *rbtree, struct rbnode __arena *node);
ret = rb_insert_node(rbtree, &nodec->rbnode);
ret = rb_insert_node(rbtree, &nodec->rbnode);
ret = rb_insert_node(rbtree, node);
if (!rb_insert_node(alloc, node))
if (rb_insert_node(noalloc, node))