1 /*
   2  * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
   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.g1;
  26 
  27 import java.util.ArrayList;
  28 import java.util.List;
  29 import java.util.Observable;
  30 import java.util.Observer;
  31 import sun.jvm.hotspot.debugger.Address;
  32 import sun.jvm.hotspot.memory.CompactibleSpace;
  33 import sun.jvm.hotspot.memory.MemRegion;
  34 import sun.jvm.hotspot.runtime.VM;
  35 import sun.jvm.hotspot.types.AddressField;
  36 import sun.jvm.hotspot.types.CIntegerField;
  37 import sun.jvm.hotspot.types.Type;
  38 import sun.jvm.hotspot.types.TypeDataBase;
  39 
  40 // Mirror class for HeapRegion. Currently we don't actually include
  41 // any of its fields but only iterate over it.
  42 
  43 public class HeapRegion extends CompactibleSpace {
  44     // static int GrainBytes;
  45     static private CIntegerField grainBytesField;
  46     static private AddressField topField;
  47 
  48     static {
  49         VM.registerVMInitializedObserver(new Observer() {
  50                 public void update(Observable o, Object data) {
  51                     initialize(VM.getVM().getTypeDataBase());
  52                 }
  53             });
  54     }
  55 
  56     static private synchronized void initialize(TypeDataBase db) {
  57         Type type = db.lookupType("HeapRegion");
  58 
  59         grainBytesField = type.getCIntegerField("GrainBytes");
  60         topField = type.getAddressField("_top");
  61 
  62     }
  63 
  64     static public long grainBytes() {
  65         return grainBytesField.getValue();
  66     }
  67 
  68     public HeapRegion(Address addr) {
  69         super(addr);
  70     }
  71 
  72     public Address top() {
  73         return topField.getValue(addr);
  74     }
  75 
  76     @Override
  77     public List getLiveRegions() {
  78         List res = new ArrayList();
  79         res.add(new MemRegion(bottom(), top()));
  80         return res;
  81     }
  82 
  83     @Override
  84     public long used() {
  85         return top().minus(bottom());
  86     }
  87 
  88     @Override
  89     public long free() {
  90         return end().minus(top());
  91     }
  92 }