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.*;
  31 import sun.jvm.hotspot.code.*;
  32 import sun.jvm.hotspot.debugger.*;
  33 import sun.jvm.hotspot.runtime.*;
  34 import sun.jvm.hotspot.types.*;
  35 import sun.jvm.hotspot.memory.*;
  36 
  37 public class EpsilonHeap extends CollectedHeap {
  38 
  39   private static AddressField spaceField;
  40   private static Field virtualSpaceField;
  41   private ContiguousSpace space;
  42   private VirtualSpace virtualSpace;
  43 
  44   static {
  45     VM.registerVMInitializedObserver(new Observer() {
  46         public void update(Observable o, Object data) {
  47           initialize(VM.getVM().getTypeDataBase());
  48         }
  49       });
  50   }
  51 
  52   private static void initialize(TypeDataBase db) {
  53     Type type = db.lookupType("EpsilonHeap");
  54     spaceField = type.getAddressField("_space");
  55     virtualSpaceField = type.getField("_virtual_space");
  56   }
  57 
  58   public EpsilonHeap(Address addr) {
  59     super(addr);
  60     space = new ContiguousSpace(spaceField.getValue(addr));
  61     virtualSpace = new VirtualSpace(addr.addOffsetTo(virtualSpaceField.getOffset()));
  62   }
  63 
  64   @Override
  65   public CollectedHeapName kind() {
  66     return CollectedHeapName.EPSILON;
  67   }
  68 
  69   @Override
  70   public long capacity() {
  71     return space.capacity();
  72   }
  73 
  74   @Override
  75   public long used() {
  76     return space.used();
  77   }
  78 
  79   public ContiguousSpace space() {
  80     return space;
  81   }
  82 
  83   @Override
  84   public void printOn(PrintStream tty) {
  85      MemRegion mr = reservedRegion();
  86      tty.println("Epsilon heap");
  87      tty.println(" reserved:  [" + mr.start() + ", " + mr.end() + "]");
  88      tty.println(" committed: [" + virtualSpace.low() + ", " + virtualSpace.high() + "]");
  89      tty.println(" used:      [" + space.bottom() + ", " + space.top() + "]");
  90   }
  91 
  92 }