1 /*
   2  * Copyright (c) 2007, 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.memory;
  26 
  27 import java.io.*;
  28 import java.util.*;
  29 import sun.jvm.hotspot.debugger.*;
  30 import sun.jvm.hotspot.runtime.*;
  31 import sun.jvm.hotspot.types.*;
  32 
  33 public class CMSCollector extends VMObject {
  34   private static long markBitMapFieldOffset;
  35 
  36   public CMSCollector(Address addr) {
  37     super(addr);
  38   }
  39 
  40   static {
  41     VM.registerVMInitializedObserver(new Observer() {
  42         public void update(Observable o, Object data) {
  43           initialize(VM.getVM().getTypeDataBase());
  44         }
  45       });
  46   }
  47 
  48   private static synchronized void initialize(TypeDataBase db) {
  49     Type type = db.lookupType("CMSCollector");
  50     markBitMapFieldOffset = type.getField("_markBitMap").getOffset();
  51   }
  52 
  53   //Accessing mark bitmap
  54   public CMSBitMap markBitMap() {
  55    return (CMSBitMap) VMObjectFactory.newObject(
  56                                 CMSBitMap.class,
  57                                 addr.addOffsetTo(markBitMapFieldOffset));
  58   }
  59 
  60   public long blockSizeUsingPrintezisBits(Address addr) {
  61     CMSBitMap markBitMap = markBitMap();
  62     long addressSize = VM.getVM().getAddressSize();
  63     if ( markBitMap.isMarked(addr) &&  markBitMap.isMarked(addr.addOffsetTo(1*addressSize)) ) {
  64       Address nextOneAddr = markBitMap.getNextMarkedWordAddress(addr.addOffsetTo(2*addressSize));
  65       //return size in bytes
  66       long size =  (nextOneAddr.addOffsetTo(1*addressSize)).minus(addr);
  67       return size;
  68     } else {
  69       //missing Printezis marks
  70       return -1;
  71     }
  72 
  73   }
  74 }