1 /*
   2  * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.gc.epsilon;
  26 
  27 import java.io.*;
  28 import java.util.*;
  29 
  30 import sun.jvm.hotspot.gc.shared.CollectedHeap;
  31 import sun.jvm.hotspot.gc.shared.CollectedHeapName;
  32 import sun.jvm.hotspot.code.*;
  33 import sun.jvm.hotspot.debugger.*;
  34 import sun.jvm.hotspot.runtime.*;
  35 import sun.jvm.hotspot.types.*;
  36 import sun.jvm.hotspot.memory.*;
  37 
  38 public class EpsilonHeap extends CollectedHeap {
  39 
  40   private static Field spaceField;
  41   private VirtualSpace space;
  42 
  43   static {
  44     VM.registerVMInitializedObserver(new Observer() {
  45         public void update(Observable o, Object data) {
  46           initialize(VM.getVM().getTypeDataBase());
  47         }
  48       });
  49   }
  50 
  51   private static void initialize(TypeDataBase db) {
  52     Type type = db.lookupType("EpsilonHeap");
  53     spaceField = type.getField("_virtual_space");
  54   }
  55 
  56   public EpsilonHeap(Address addr) {
  57     super(addr);
  58     space = new VirtualSpace(addr.addOffsetTo(spaceField.getOffset()));
  59   }
  60 
  61   @Override
  62   public CollectedHeapName kind() {
  63     return CollectedHeapName.EPSILON;
  64   }
  65 
  66   public VirtualSpace space() {
  67     return space;
  68   }
  69 
  70   @Override
  71   public void printOn(PrintStream tty) {
  72      MemRegion mr = reservedRegion();
  73      tty.println("Epsilon heap");
  74      tty.println(" reserved: [" + mr.start() + ", " + mr.end() + "]");
  75      tty.println(" committed: [" + space.low() + ", " + space.high() + "]");
  76   }
  77 
  78 }