diff --git a/include/xo/alloc2/padding.hpp b/include/xo/alloc2/padding.hpp
deleted file mode 100644
index 10d03b8..0000000
--- a/include/xo/alloc2/padding.hpp
+++ /dev/null
@@ -1,60 +0,0 @@
-/** @file padding.hpp
- *
- *  @author Roland Conybeare, Dec 2025
- **/
-
-#pragma once
-
-#include <memory>
-#include <cstdint>
-
-namespace xo {
-    namespace mm {
-
-        struct padding {
-            /** word size for alignment**/
-            static constexpr std::size_t c_alloc_alignment = sizeof(std::uintptr_t);
-
-            static inline std::size_t is_aligned(std::size_t n,
-                                                 std::size_t align = c_alloc_alignment) {
-                return n % align == 0;
-            }
-
-            /** how much to add to @p z to get a multiple of
-             *  @ref c_alloc_alignment
-             **/
-            static inline std::size_t alloc_padding(std::size_t z,
-                                                    std::size_t align = c_alloc_alignment)
-                {
-
-                    /* round up to multiple of c_bpw, but map 0 -> 0
-                     * (table assuming c_bpw==8)
-                     *
-                     *   z%c_bpw   dz
-                     *   ------------
-                     *         0    0
-                     *         1    7
-                     *         2    6
-                     *        ..   ..
-                     *         7    1
-                     */
-                    std::size_t dz = (align - (z % align)) % align;
-
-                    return dz;
-                }
-
-            /** @p z rounded up to an exact multiple
-             *  of @ref c_alloc_alignment
-             **/
-            static inline
-            std::size_t with_padding(std::size_t z,
-                                     std::size_t align = c_alloc_alignment)
-                {
-                    return z + alloc_padding(z, align);
-                }
-        };
-
-    } /*namespace mm*/
-} /*namespace xo*/
-
-/* end padding.hpp */
diff --git a/src/alloc2/DArena.cpp b/src/alloc2/DArena.cpp
index 82557e4..c20d34b 100644
--- a/src/alloc2/DArena.cpp
+++ b/src/alloc2/DArena.cpp
@@ -6,9 +6,9 @@
 #include "alloc/AAllocator.hpp"
 #include "arena/DArena.hpp"
 #include "arena/DArenaIterator.hpp"
-#include "xo/alloc2/padding.hpp"
-#include "xo/indentlog/scope.hpp"
-#include "xo/indentlog/print/tag.hpp"
+#include <xo/arena/padding.hpp>
+#include <xo/indentlog/scope.hpp>
+#include <xo/indentlog/print/tag.hpp>
 #include <cassert>
 #include <sys/mman.h> // for ::munmap()
 #include <unistd.h> // for ::getpagesize()
diff --git a/utest/arena.test.cpp b/utest/arena.test.cpp
index 6c3278b..9bd8720 100644
--- a/utest/arena.test.cpp
+++ b/utest/arena.test.cpp
@@ -5,11 +5,9 @@
 
 #include "xo/alloc2/Allocator.hpp"
 #include "xo/alloc2/alloc/IAllocator_Xfer.hpp"
-//#include "xo/alloc2/DArena.hpp"
 #include "xo/alloc2/arena/IAllocator_DArena.hpp"
-//#include "xo/alloc2/alloc/RAllocator.hpp"
 #include "xo/alloc2/print.hpp"
-#include "xo/alloc2/padding.hpp"
+#include "xo/arena/padding.hpp"
 #include <xo/facet/obj.hpp>
 #include <xo/indentlog/scope.hpp>
 #include <catch2/catch.hpp>