1 /*

     2  * Copyright (c) 2007, 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.cms;

    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 }