diff --git a/src/page.c b/src/page.c
index 03b24932..9a32b1d3 100644
--- a/src/page.c
+++ b/src/page.c
@@ -740,10 +740,11 @@ void _mi_deferred_free(mi_heap_t* heap, bool force) {
   if (!heap->tld->recurse) {
     heap->tld->recurse = true;
     if (deferred_free != NULL) {
+      // first we invoke global deferred free function (if it is defined).
       deferred_free(force, heap->tld->heartbeat, mi_atomic_load_ptr_relaxed(void,&deferred_arg));
     }
     if (heap->deferred_free != NULL) {
-      // TODO: Should heap->deferred_free_arg be an atomic load? 
+      // invoke deferred free function that is defined to do deferred free on specific heap instance.  
       (heap->deferred_free)(heap, force, heap->tld->heartbeat, heap->deferred_free_arg);
     }
     heap->tld->recurse = false;