diff --git a/ChangeLog b/ChangeLog
index a41e9232a4..8c16c1820a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Mar 31 10:28:01 2014  Eric Wong  <e@80x24.org>
+
+	* st.c (st_init_table_with_size): update comment
+	  [Feature #9425]
+
 Sun Mar 30 23:39:26 2014  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.c (rb_w32_accept, open_ifs_socket, socketpair_internal):
diff --git a/st.c b/st.c
index 5a0b62a664..ccf22eef4d 100644
--- a/st.c
+++ b/st.c
@@ -201,7 +201,7 @@ st_init_table_with_size(const struct st_hash_type *type, st_index_t size)
 	size = ST_DEFAULT_PACKED_TABLE_SIZE;
     }
     else {
-	size = new_size(size);	/* round up to prime number */
+	size = new_size(size);	/* round up to power-of-two */
     }
     tbl->num_bins = size;
     tbl->bins = st_alloc_bins(size);