diff --git a/vm_core.h b/vm_core.h
index 88ff913a04..4f6e07d818 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -504,12 +504,14 @@ struct rb_iseq_constant_body {
     const rb_iseq_t *mandatory_only_iseq;
 
 #if USE_MJIT || USE_YJIT
-    /* The following fields are MJIT related info.  */
-    VALUE (*jit_func)(struct rb_execution_context_struct *,
-                      struct rb_control_frame_struct *); /* function pointer for loaded native code */
-    long unsigned total_calls; /* number of total calls with `jit_exec()` */
+    // Function pointer for JIT code
+    VALUE (*jit_func)(struct rb_execution_context_struct *, struct rb_control_frame_struct *);
+    // Number of total calls with jit_exec()
+    long unsigned total_calls;
 #endif
+
 #if USE_MJIT
+    // MJIT stores some data on each iseq.
     struct rb_mjit_unit *mjit_unit;
 #endif