1 /*

     2  * @(#)AdaptiveFreeList.java

     3  *

     4  * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

     5  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     6  *

     7  * This code is free software; you can redistribute it and/or modify it

     8  * under the terms of the GNU General Public License version 2 only, as

     9  * published by the Free Software Foundation.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  *

    25  */

    26 

    27 package sun.jvm.hotspot.gc.cms;

    28 

    29 import java.util.Observable;

    30 import java.util.Observer;

    31 

    32 import sun.jvm.hotspot.debugger.Address;

    33 import sun.jvm.hotspot.runtime.VM;

    34 import sun.jvm.hotspot.runtime.VMObject;

    35 import sun.jvm.hotspot.types.CIntegerField;

    36 import sun.jvm.hotspot.types.Type;

    37 import sun.jvm.hotspot.types.TypeDataBase;

    38 

    39 public class AdaptiveFreeList extends VMObject {

    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("AdaptiveFreeList<FreeChunk>");

    50     sizeField = type.getCIntegerField("_size");

    51     countField = type.getCIntegerField("_count");

    52     headerSize = type.getSize();

    53   }

    54 

    55   // Fields

    56   private static CIntegerField sizeField;

    57   private static CIntegerField countField;

    58   private static long          headerSize;

    59 

    60   //Constructor

    61   public AdaptiveFreeList(Address address) {

    62     super(address);

    63   }

    64 

    65   // Accessors

    66   public long size() {

    67     return sizeField.getValue(addr);

    68   }

    69 

    70   public long count() {

    71     return  countField.getValue(addr);

    72   }

    73 

    74   public static long sizeOf() {

    75     return headerSize;

    76   }

    77 }