diff --git a/ChangeLog b/ChangeLog
index 24dcb1134e..6293fa5395 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Dec 10 06:33:39 2015  Eric Wong  <e@80x24.org>
+
+	* marshal.c (memsize_dump_arg): remove NULL check
+	  (memsize_load_arg): ditto
+
 Thu Dec 10 05:53:18 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* tool/mkconfig.rb: rbconfig must not be fronzen-string-literal to
diff --git a/marshal.c b/marshal.c
index 8bc80194c0..d67ce87145 100644
--- a/marshal.c
+++ b/marshal.c
@@ -207,7 +207,7 @@ free_dump_arg(void *ptr)
 static size_t
 memsize_dump_arg(const void *ptr)
 {
-    return ptr ? sizeof(struct dump_arg) : 0;
+    return sizeof(struct dump_arg);
 }
 
 static const rb_data_type_t dump_arg_data = {
@@ -1091,7 +1091,7 @@ free_load_arg(void *ptr)
 static size_t
 memsize_load_arg(const void *ptr)
 {
-    return ptr ? sizeof(struct load_arg) : 0;
+    return sizeof(struct load_arg);
 }
 
 static const rb_data_type_t load_arg_data = {