src/hotspot/share/gc/z/zArguments.cpp

@@ -68,10 +68,22 @@
 
   if (ConcGCThreads == 0) {
     vm_exit_during_initialization("The flag -XX:+UseZGC can not be combined with -XX:ConcGCThreads=0");
   }
 
+  // Select medium page size so that we can calculate the max reserve
+  ZHeuristics::set_medium_page_size();
+
+  // MinHeapSize/InitialHeapSize must be at least as large as the max reserve
+  const size_t max_reserve = ZHeuristics::max_reserve();
+  if (MinHeapSize < max_reserve) {
+    FLAG_SET_ERGO(MinHeapSize, max_reserve);
+  }
+  if (InitialHeapSize < max_reserve) {
+    FLAG_SET_ERGO(InitialHeapSize, max_reserve);
+  }
+
 #ifdef COMPILER2
   // Enable loop strip mining by default
   if (FLAG_IS_DEFAULT(UseCountedLoopSafepoints)) {
     FLAG_SET_DEFAULT(UseCountedLoopSafepoints, true);
     if (FLAG_IS_DEFAULT(LoopStripMiningIter)) {