diff --git a/ChangeLog b/ChangeLog
index 1c12fbe97e..e8e0e37d9c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,8 @@ Changes in version 0.2.0.31 - 2008-08-??
  o Minor bugfixes:
     - Fix a small alignment and memory-wasting bug on buffer chunks.  Spotted
       by rovv.
+    - Recover 3-7 bytes that were wasted per memory chunk.  Fixes bug
+      794; bug spotted by rovv.  Bugfix on 0.2.0.1-alpha.
 
 
 Changes in version 0.2.0.30 - 2008-07-15
diff --git a/src/common/mempool.c b/src/common/mempool.c
index 6a41d220fe..d489cf6550 100644
--- a/src/common/mempool.c
+++ b/src/common/mempool.c
@@ -144,7 +144,7 @@ struct mp_chunk_t {
 };
 
 /** Number of extra bytes needed beyond mem_size to allocate a chunk. */
-#define CHUNK_OVERHEAD (sizeof(mp_chunk_t)-1)
+#define CHUNK_OVERHEAD STRUCT_OFFSET(mp_chunk_t, mem[0])
 
 /** Given a pointer to a mp_allocated_t, return a pointer to the memory
  * item it holds. */