diff --git a/ChangeLog b/ChangeLog
index 7f567b0ce2..9dffbed6f4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Oct  3 05:58:58 2014  Eric Wong  <e@80x24.org>
+
+	* vm_trace.c (rb_tp_t): pack 56 => 48 bytes on 64-bit
+
 Thu Oct  2 18:41:45 2014  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/etc/etc.c (etc_nprocessors): Windows support.
diff --git a/vm_trace.c b/vm_trace.c
index 65a53d4d04..c410be7138 100644
--- a/vm_trace.c
+++ b/vm_trace.c
@@ -640,11 +640,11 @@ static VALUE rb_cTracePoint;
 
 typedef struct rb_tp_struct {
     rb_event_flag_t events;
+    int tracing; /* bool */
     rb_thread_t *target_th;
     void (*func)(VALUE tpval, void *data);
     void *data;
     VALUE proc;
-    int tracing;
     VALUE self;
 } rb_tp_t;