src/share/vm/runtime/arguments.hpp

@@ -219,10 +219,21 @@
     arg_too_big    = -1,
     arg_in_range   = 0
   };
 
  private:
+  // should ergenomics be applied to the ClassMetaspaceSize?
+  static bool apply_ergonomics_on_classmetaspacesize();
+
+  // Value of the ergonomically determined ClassMetaspaceSize
+  // 100,000 classes seems like a good size, so 100M assumes around 1K
+  // per klass.   The vtable and oopMap is embedded so we don't have a fixed
+  // size per klass.   Eventually, this will be parameterized because it
+  // would also be useful to determine the optimal size of the
+  // systemDictionary.
+  // Round up to a power of two to avoid losses due to alignment.
+  static const size_t ErgoClassMetaspaceSize = 128 * M;
 
   // an array containing all flags specified in the .hotspotrc file
   static char** _jvm_flags_array;
   static int    _num_jvm_flags;
   // an array containing all jvm arguments specified in the command line

@@ -262,10 +273,13 @@
 
   // Option flags
   static bool   _has_profile;
   static bool   _has_alloc_profile;
   static const char*  _gc_log_filename;
+  // computed value for the maximum heap alignment
+  static size_t  _max_heap_alignment;
+
   static uintx  _min_heap_size;
 
   // -Xrun arguments
   static AgentLibraryList _libraryList;
   static void add_init_library(const char* name, char* options)

@@ -307,10 +321,11 @@
   // UseParallel[Old]GC
   static void set_parallel_gc_flags();
   // Garbage-First (UseG1GC)
   static void set_g1_gc_flags();
   // GC ergonomics
+  static void set_max_heap_alignment();
   static void set_use_compressed_oops();
   static void set_ergonomics_flags();
   static void set_shared_spaces_flags();
   // limits the given memory size by the maximum amount of memory this process is
   // currently allowed to allocate or reserve.

@@ -424,10 +439,14 @@
   // Check stack pages settings
   static bool check_stack_pages();
   // Used by os_solaris
   static bool process_settings_file(const char* file_name, bool should_exist, jboolean ignore_unrecognized);
 
+  static size_t max_heap_alignment()       { return _max_heap_alignment; }
+  // return the maximum size a heap with compressed oops can take
+  static size_t max_heap_for_compressed_oops();
+
   // return a char* array containing all options
   static char** jvm_flags_array()          { return _jvm_flags_array; }
   static char** jvm_args_array()           { return _jvm_args_array; }
   static int num_jvm_flags()               { return _num_jvm_flags; }
   static int num_jvm_args()                { return _num_jvm_args; }