--- old/src/hotspot/share/gc/shared/gcVMOperations.hpp	2020-07-09 14:50:44.144351924 +0800
+++ new/src/hotspot/share/gc/shared/gcVMOperations.hpp	2020-07-09 14:50:43.992352408 +0800
@@ -125,10 +125,10 @@
  private:
   outputStream* _out;
   bool _full_gc;
-  size_t _parallel_thread_num;
+  uint _parallel_thread_num;
  public:
   VM_GC_HeapInspection(outputStream* out, bool request_full_gc,
-                       size_t parallel_thread_num = 1) :
+                       uint parallel_thread_num = 1) :
     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
                     GCCause::_heap_inspection /* GC Cause */,
                     0 /* total full collections, dummy, ignored */,