Java example source code file (ageTable.hpp)

This example Java source code file (ageTable.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

perfvariable, share_vm_gc_implementation_shared_agetable_hpp, value_obj_class_spec, vmstructs

The ageTable.hpp Java example source code

/*
 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP

#include "oops/markOop.hpp"
#include "oops/oop.hpp"
#include "runtime/perfData.hpp"

/* Copyright (c) 1992-2009 Oracle and/or its affiliates, and Stanford University.
   See the LICENSE file for license information. */

// Age table for adaptive feedback-mediated tenuring (scavenging)
//
// Note: all sizes are in oops

class ageTable VALUE_OBJ_CLASS_SPEC {
  friend class VMStructs;

 public:
  // constants
  enum { table_size = markOopDesc::max_age + 1 };

  // instance variables
  size_t sizes[table_size];

  // constructor.  "global" indicates that this is the global age table
  // (as opposed to gc-thread-local)
  ageTable(bool global = true);

  // clear table
  void clear();

  // add entry
  void add(oop p, size_t oop_size) {
    uint age = p->age();
    assert(age > 0 && age < table_size, "invalid age of object");
    sizes[age] += oop_size;
  }

  // Merge another age table with the current one.  Used
  // for parallel young generation gc.
  void merge(ageTable* subTable);
  void merge_par(ageTable* subTable);

  // calculate new tenuring threshold based on age information
  uint compute_tenuring_threshold(size_t survivor_capacity);

 private:
  PerfVariable* _perf_sizes[table_size];
};

#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_AGETABLE_HPP