-// Generic radix tree implementation. It's only kernel-specific because
-// it uses the kernel page allocator; each node takes up one page. The
-// depth of the tree is dynamically growable (but not currently
-// shrinkable).
+// This is like RadixTree, but it uses the kernel page allocator; each
+// node takes up one page. The depth of the tree is dynamically growable
+// (but not currently shrinkable). It also auto-guesses radix_bits based
+// on the size of T, so as to fit a page.