diff --git a/src/mem/alloc.h b/src/mem/alloc.h
index 38c89d1..096ad47 100644
--- a/src/mem/alloc.h
+++ b/src/mem/alloc.h
@@ -38,7 +38,10 @@ namespace snmalloc
     PMMediumslab = 2
   };
 
-  using SuperslabPagemap = Pagemap<SUPERSLAB_BITS, uint8_t, 0>;
+  using SuperslabPagemap = std::conditional_t<
+    bits::is64(),
+    Pagemap<SUPERSLAB_BITS, uint8_t, 0>,
+    FlatPagemap<SUPERSLAB_BITS, uint8_t>>;
 
   HEADER_GLOBAL SuperslabPagemap global_pagemap;
   /**
@@ -131,7 +134,7 @@ namespace snmalloc
   };
 
   static_assert(
-    SUPERSLAB_SIZE == Pagemap<SUPERSLAB_BITS, size_t, 0>::GRANULARITY,
+    SUPERSLAB_SIZE == SuperslabPagemap::GRANULARITY,
     "The superslab size should be the same as the pagemap granularity");
 
 #ifndef SNMALLOC_DEFAULT_PAGEMAP
diff --git a/src/mem/pagemap.h b/src/mem/pagemap.h
index 20b01e2..e0e73b1 100644
--- a/src/mem/pagemap.h
+++ b/src/mem/pagemap.h
@@ -21,6 +21,10 @@ namespace snmalloc
     static constexpr size_t CONTENT_BITS =
       bits::next_pow2_bits_const(sizeof(T));
 
+    static_assert(
+      PAGEMAP_BITS - CONTENT_BITS < COVERED_BITS,
+      "Should use the FlatPageMap as it does not require a tree");
+
     static constexpr size_t BITS_FOR_LEAF = PAGEMAP_BITS - CONTENT_BITS;
     static constexpr size_t ENTRIES_PER_LEAF = 1 << BITS_FOR_LEAF;
     static constexpr size_t LEAF_MASK = ENTRIES_PER_LEAF - 1;
@@ -224,4 +228,44 @@ namespace snmalloc
       } while (length > 0);
     }
   };
+
+  template<size_t GRANULARITY_BITS, typename T>
+  class FlatPagemap
+  {
+  private:
+    static constexpr size_t COVERED_BITS =
+      bits::ADDRESS_BITS - GRANULARITY_BITS;
+    static constexpr size_t CONTENT_BITS =
+      bits::next_pow2_bits_const(sizeof(T));
+    static constexpr size_t ENTRIES = 1ULL << (COVERED_BITS + CONTENT_BITS);
+    static constexpr size_t SHIFT = GRANULARITY_BITS;
+
+  public:
+    static constexpr size_t GRANULARITY = 1 << GRANULARITY_BITS;
+
+  private:
+    std::atomic<T> top[ENTRIES];
+
+  public:
+    T get(void* p)
+    {
+      return top[(size_t)p >> SHIFT].load(std::memory_order_relaxed);
+    }
+
+    void set(void* p, T x)
+    {
+      top[(size_t)p >> SHIFT].store(x, std::memory_order_relaxed);
+    }
+
+    void set_range(void* p, T x, size_t length)
+    {
+      size_t index = (size_t)p >> SHIFT;
+      do
+      {
+        top[index].store(x, std::memory_order_relaxed);
+        index++;
+        length--;
+      } while (length > 0);
+    }
+  };
 }