diff -r c97db0855565 -r 758c07667682 src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp
--- a/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Tue Feb 04 17:38:01 2020 +0800
+++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp	Tue Feb 04 18:13:14 2020 +0800
@@ -133,7 +133,11 @@
   SizerKind _sizer_kind;
   uint _min_desired_young_length;
   uint _max_desired_young_length;
+
+  // False when using a fixed young generation size due to command-line options,
+  // true otherwise.
   bool _adaptive_size;
+
   uint calculate_default_min_length(uint new_number_of_heap_regions);
   uint calculate_default_max_length(uint new_number_of_heap_regions);