1 /*
2 * Copyright 2003-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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.oops.*;
31 import sun.jvm.hotspot.runtime.*;
32 import sun.jvm.hotspot.types.*;
33 import sun.jvm.hotspot.utilities.*;
34
35 public class CompactibleFreeListSpace extends CompactibleSpace {
36 private static AddressField collectorField;
37
38 static {
39 VM.registerVMInitializedObserver(new Observer() {
40 public void update(Observable o, Object data) {
41 initialize(VM.getVM().getTypeDataBase());
42 }
43 });
44 }
45
46 private static synchronized void initialize(TypeDataBase db) {
47 long sizeofFreeChunk = db.lookupType("FreeChunk").getSize();
48 VM vm = VM.getVM();
49 MinChunkSizeInBytes = numQuanta(sizeofFreeChunk, vm.getMinObjAlignmentInBytes()) *
50 vm.getMinObjAlignmentInBytes();
51
52 Type type = db.lookupType("CompactibleFreeListSpace");
53 collectorField = type.getAddressField("_collector");
54 }
55
56 public CompactibleFreeListSpace(Address addr) {
57 super(addr);
58 }
59
60 // Accessing block offset table
61 public CMSCollector collector() {
62 return (CMSCollector) VMObjectFactory.newObject(
63 CMSCollector.class,
64 collectorField.getValue(addr));
65 }
66
67 public long used() {
68 List regions = getLiveRegions();
69 long usedSize = 0L;
70 for (Iterator itr = regions.iterator(); itr.hasNext();) {
71 MemRegion mr = (MemRegion) itr.next();
72 usedSize += mr.byteSize();
73 }
74 return usedSize;
75 }
76
77 public long free() {
78 return capacity() - used();
79 }
80
81 public void printOn(PrintStream tty) {
82 tty.print("free-list-space");
83 }
84
85 public Address skipBlockSizeUsingPrintezisBits(Address pos) {
86 CMSCollector collector = collector();
87 long size = 0;
88 Address addr = null;
89
90 if (collector != null) {
91 size = collector.blockSizeUsingPrintezisBits(pos);
92 if (size >= 3) {
93 addr = pos.addOffsetTo(adjustObjectSizeInBytes(size));
94 }
95 }
96 return addr;
97 }
98
99 public List/*<MemRegion>*/ getLiveRegions() {
100 List res = new ArrayList(); // List<MemRegion>
101 VM vm = VM.getVM();
102 Debugger dbg = vm.getDebugger();
103 ObjectHeap heap = vm.getObjectHeap();
104 Address cur = bottom();
105 Address regionStart = cur;
106 Address limit = end();
107 final long addressSize = vm.getAddressSize();
108
109 for (; cur.lessThan(limit);) {
110 Address klassOop = cur.getAddressAt(addressSize);
111 // FIXME: need to do a better job here.
112 // can I use bitMap here?
113 if (klassOop == null) {
114 //Find the object size using Printezis bits and skip over
115 System.err.println("Finding object size using Printezis bits and skipping over...");
116 long size = collector().blockSizeUsingPrintezisBits(cur);
117 if (size == -1) {
118 System.err.println("Printezis bits not set...");
119 break;
120 }
121 cur = cur.addOffsetTo(adjustObjectSizeInBytes(size));
122 }
123
124 if (FreeChunk.secondWordIndicatesFreeChunk(dbg.getAddressValue(klassOop))) {
125 if (! cur.equals(regionStart)) {
126 res.add(new MemRegion(regionStart, cur));
127 }
128 FreeChunk fc = (FreeChunk) VMObjectFactory.newObject(FreeChunk.class, cur);
129 long chunkSize = fc.size();
130 if (Assert.ASSERTS_ENABLED) {
131 Assert.that(chunkSize > 0, "invalid FreeChunk size");
132 }
133 // note that fc.size() gives chunk size in heap words
134 cur = cur.addOffsetTo(chunkSize * addressSize);
135 System.err.println("Free chunk in CMS heap, size="+chunkSize * addressSize);
136 regionStart = cur;
137 } else if (klassOop != null) {
138 Oop obj = heap.newOop(cur.addOffsetToAsOopHandle(0));
139 long objectSize = obj.getObjectSize();
140 cur = cur.addOffsetTo(adjustObjectSizeInBytes(objectSize));
141 }
142 }
143 return res;
144 }
145
146 //-- Internals only below this point
147
148 // Unlike corresponding VM code, we operate on byte size rather than
149 // HeapWord size for convenience.
150
151 private static long numQuanta(long x, long y) {
152 return ((x+y-1)/y);
153 }
154
155 public static long adjustObjectSizeInBytes(long sizeInBytes) {
156 return Oop.alignObjectSize(Math.max(sizeInBytes, MinChunkSizeInBytes));
157 }
158
159 // FIXME: should I read this directly from VM?
160 private static long MinChunkSizeInBytes;
161 }