0
|
1 /*
|
|
2 * Copyright 2004-2006 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.runtime;
|
|
26
|
|
27 import sun.jvm.hotspot.debugger.*;
|
|
28 import sun.jvm.hotspot.memory.*;
|
|
29 import sun.jvm.hotspot.oops.*;
|
|
30 import java.io.*;
|
|
31 import java.util.*;
|
|
32 import java.util.Map.Entry;
|
|
33
|
|
34 /** Prints information about Java-level deadlocks in supplied 'tty'. */
|
|
35
|
|
36 public class DeadlockDetector {
|
|
37
|
|
38 public static void print(PrintStream tty) {
|
|
39 print(tty, true);
|
|
40 }
|
|
41
|
|
42 /** prints zero or more deadlocks into 'tty' taking current
|
|
43 snapshot of Java threads and locks */
|
|
44 public static void print(PrintStream tty, boolean concurrentLocks) {
|
|
45 tty.println("Deadlock Detection:");
|
|
46 tty.println();
|
|
47
|
|
48 int globalDfn = 0, thisDfn;
|
|
49 int numberOfDeadlocks = 0;
|
|
50 JavaThread currentThread = null, previousThread = null;
|
|
51 ObjectMonitor waitingToLockMonitor = null;
|
|
52 Oop waitingToLockBlocker = null;
|
|
53
|
|
54 threads = VM.getVM().getThreads();
|
|
55 heap = VM.getVM().getObjectHeap();
|
|
56 createThreadTable();
|
|
57
|
|
58 Iterator i = threadTable.entrySet().iterator();
|
|
59 while (i.hasNext()) {
|
|
60 Entry e = (Entry)i.next();
|
|
61 if (dfn(e) >= 0) {
|
|
62 // this thread was already visited
|
|
63 continue;
|
|
64 }
|
|
65
|
|
66 thisDfn = globalDfn;
|
|
67 JavaThread thread = (JavaThread)e.getKey();
|
|
68 previousThread = thread;
|
|
69
|
|
70 // When there is a deadlock, all the monitors involved in the dependency
|
|
71 // cycle must be contended and heavyweight. So we only care about the
|
|
72 // heavyweight monitor a thread is waiting to lock.
|
|
73 try {
|
|
74 waitingToLockMonitor = thread.getCurrentPendingMonitor();
|
|
75 } catch (RuntimeException re) {
|
|
76 tty.println("This version of HotSpot VM doesn't support deadlock detection.");
|
|
77 return;
|
|
78 }
|
|
79
|
|
80 Klass abstractOwnableSyncKlass = null;
|
|
81 if (concurrentLocks) {
|
|
82 waitingToLockBlocker = thread.getCurrentParkBlocker();
|
|
83 SystemDictionary sysDict = VM.getVM().getSystemDictionary();
|
|
84 abstractOwnableSyncKlass = sysDict.getAbstractOwnableSynchronizerKlass();
|
|
85 }
|
|
86
|
|
87 while (waitingToLockMonitor != null ||
|
|
88 waitingToLockBlocker != null) {
|
|
89 if (waitingToLockMonitor != null) {
|
|
90 currentThread = threads.owningThreadFromMonitor(waitingToLockMonitor);
|
|
91 } else {
|
|
92 if (concurrentLocks) {
|
|
93 if (waitingToLockBlocker.isA(abstractOwnableSyncKlass)) {
|
|
94 Oop threadOop = OopUtilities.abstractOwnableSynchronizerGetOwnerThread(waitingToLockBlocker);
|
|
95 if (threadOop != null) {
|
|
96 currentThread = OopUtilities.threadOopGetJavaThread(threadOop);
|
|
97 }
|
|
98 }
|
|
99 }
|
|
100 }
|
|
101 if (currentThread == null) {
|
|
102 // No dependency on another thread
|
|
103 break;
|
|
104 }
|
|
105 if (dfn(currentThread) < 0) {
|
|
106 // First visit to this thread
|
|
107 threadTable.put(currentThread, new Integer(globalDfn++));
|
|
108 } else if (dfn(currentThread) < thisDfn) {
|
|
109 // Thread already visited, and not on a (new) cycle
|
|
110 break;
|
|
111 } else if (currentThread == previousThread) {
|
|
112 // Self-loop, ignore
|
|
113 break;
|
|
114 } else {
|
|
115 // We have a (new) cycle
|
|
116 numberOfDeadlocks ++;
|
|
117 printOneDeadlock(tty, currentThread, concurrentLocks);
|
|
118 break;
|
|
119 }
|
|
120 previousThread = currentThread;
|
|
121 waitingToLockMonitor = (ObjectMonitor)currentThread.getCurrentPendingMonitor();
|
|
122 if (concurrentLocks) {
|
|
123 waitingToLockBlocker = currentThread.getCurrentParkBlocker();
|
|
124 }
|
|
125 }
|
|
126 }
|
|
127
|
|
128 switch (numberOfDeadlocks) {
|
|
129 case 0:
|
|
130 tty.println("No deadlocks found.");
|
|
131 break;
|
|
132 case 1:
|
|
133 tty.println("Found a total of 1 deadlock.");
|
|
134 break;
|
|
135 default:
|
|
136 tty.println("Found a total of " + numberOfDeadlocks + " deadlocks.");
|
|
137 break;
|
|
138 }
|
|
139 tty.println();
|
|
140 }
|
|
141
|
|
142 //-- Internals only below this point
|
|
143 private static Threads threads;
|
|
144 private static ObjectHeap heap;
|
|
145 private static HashMap threadTable;
|
|
146
|
|
147 private static void createThreadTable() {
|
|
148 threadTable = new HashMap();
|
|
149 for (JavaThread cur = threads.first(); cur != null; cur = cur.next()) {
|
|
150 // initialize dfn for each thread to -1
|
|
151 threadTable.put(cur, new Integer(-1));
|
|
152 }
|
|
153 }
|
|
154
|
|
155 private static int dfn(JavaThread thread) {
|
|
156 Object obj = threadTable.get(thread);
|
|
157 if (obj != null) {
|
|
158 return ((Integer)obj).intValue();
|
|
159 }
|
|
160 return -1;
|
|
161 }
|
|
162
|
|
163 private static int dfn(Entry e) {
|
|
164 return ((Integer)e.getValue()).intValue();
|
|
165 }
|
|
166
|
|
167 private static void printOneDeadlock(PrintStream tty, JavaThread thread,
|
|
168 boolean concurrentLocks) {
|
|
169 tty.println("Found one Java-level deadlock:");
|
|
170 tty.println("=============================");
|
|
171 ObjectMonitor waitingToLockMonitor = null;
|
|
172 Oop waitingToLockBlocker = null;
|
|
173 JavaThread currentThread = thread;
|
|
174 do {
|
|
175 tty.println();
|
|
176 tty.println("\"" + currentThread.getThreadName() + "\":");
|
|
177 waitingToLockMonitor = currentThread.getCurrentPendingMonitor();
|
|
178 if (waitingToLockMonitor != null) {
|
|
179 tty.print(" waiting to lock Monitor@" + waitingToLockMonitor.getAddress());
|
|
180 OopHandle obj = waitingToLockMonitor.object();
|
|
181 Oop oop = heap.newOop(obj);
|
|
182 if (obj != null) {
|
|
183 tty.print(" (Object@");
|
|
184 Oop.printOopAddressOn(oop, tty);
|
|
185 tty.print(", a " + oop.getKlass().getName().asString() + ")" );
|
|
186 tty.print(",\n which is held by");
|
|
187 } else {
|
|
188 // No Java object associated - a raw monitor
|
|
189 tty.print(" (raw monitor),\n which is held by");
|
|
190 }
|
|
191 currentThread = threads.owningThreadFromMonitor(waitingToLockMonitor);
|
|
192 tty.print(" \"" + currentThread.getThreadName() + "\"");
|
|
193 } else if (concurrentLocks) {
|
|
194 waitingToLockBlocker = currentThread.getCurrentParkBlocker();
|
|
195 tty.print(" waiting for ownable synchronizer ");
|
|
196 Oop.printOopAddressOn(waitingToLockBlocker, tty);
|
|
197 tty.print(", (a " + waitingToLockBlocker.getKlass().getName().asString() + ")" );
|
|
198 Oop threadOop = OopUtilities.abstractOwnableSynchronizerGetOwnerThread(waitingToLockBlocker);
|
|
199 currentThread = OopUtilities.threadOopGetJavaThread(threadOop);
|
|
200 tty.print(",\n which is held by");
|
|
201 tty.print(" \"" + currentThread.getThreadName() + "\"");
|
|
202 }
|
|
203 } while (!currentThread.equals(thread));
|
|
204 tty.println();
|
|
205 tty.println();
|
|
206 }
|
|
207 }
|