1 /*
2 * Copyright (c) 2011, 2016, 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 /* @test
25 * @bug 4243978
26 * @summary Test if Reference.enqueue() works properly with pending references
27 */
28 import java.lang.ref.*;
29
30 public class ReferenceEnqueuePending {
31 static class NumberedWeakReference extends WeakReference<Integer> {
32 // Add an integer to identify the weak reference object.
33 int number;
34
35 NumberedWeakReference(Integer referent, ReferenceQueue<Integer> q, int i) {
36 super(referent, q);
37 number = i;
38 }
39 }
40
41 static final boolean debug = System.getProperty("test.debug") != null;
42 static final int iterations = 1000;
43 static final int gc_trigger = 99;
44 static int[] a = new int[2 * iterations];
45 // Keep all weak references alive with the following array.
46 static NumberedWeakReference[] b = new NumberedWeakReference[iterations];
47
48 public static void main(String[] argv) throws Exception {
49 if (debug) {
50 System.out.println("Starting the test.");
51 }
52 // Raise thread priority to match the referenceHandler
53 // priority, so that they can race also on a uniprocessor.
54 raisePriority();
55
56 ReferenceQueue<Integer> refQueue = new ReferenceQueue<>();
57
58 // Our objective is to let the mutator enqueue
59 // a Reference object that may already be in the
60 // pending state because of having been identified
61 // as weakly reachable at a previous garbage collection.
62 // To this end, we create many Reference objects, each with a
63 // a unique integer object as its referant.
64 // We let the referents become eligible for collection,
65 // while racing with the garbage collector which may
66 // have pended some of these Reference objects.
67 // Finally we check that all of the Reference objects
68 // end up on the their queue. The test was originally
69 // submitted to show that such races could break the
70 // pending list and/or the reference queue, because of sharing
71 // the same link ("next") for maintaining both lists, thus
72 // losing some of the Reference objects on either queue.
73
74 Integer obj = new Integer(0);
75 NumberedWeakReference weaky = new NumberedWeakReference(obj, refQueue, 0);
76 for (int i = 1; i < iterations; i++) {
77 // Create a new object, dropping the onlY strong reference to
78 // the previous Integer object.
79 obj = new Integer(i);
80 // Trigger gc each gc_trigger iterations.
81 if ((i % gc_trigger) == 0) {
82 forceGc(0);
83 }
84 // Enqueue every other weaky.
85 if ((i % 2) == 0) {
86 weaky.enqueue();
87 }
88 // Remember the Reference objects, for testing later.
89 b[i - 1] = weaky;
90 // Get a new weaky for the Integer object just
91 // created, which may be explicitly enqueued in
92 // our next trip around the loop.
93 weaky = new NumberedWeakReference(obj, refQueue, i);
94 }
95
96 // Do a final collection to discover and process all
97 // Reference objects created above, allowing some time
98 // for the ReferenceHandler thread to queue the References.
99 forceGc(100);
100 forceGc(100);
101
102 // Verify that all WeakReference objects ended up queued.
103 checkResult(refQueue, iterations-1);
104
105 // Ensure the final weaky is live but won't be enqueued during
106 // result checking, by ensuring its referent remains live.
107 // This eliminates behavior changes resulting from different
108 // compiler optimizations.
109 Reference.reachabilityFence(weaky);
110 Reference.reachabilityFence(obj);
111
112 System.out.println("Test passed.");
113 }
114
115 private static NumberedWeakReference waitForReference(ReferenceQueue<Integer> queue) {
116 try {
117 return (NumberedWeakReference) queue.remove(30000); // 30sec
118 } catch (InterruptedException ie) {
119 return null;
120 }
121 }
122
123 private static void checkResult(ReferenceQueue<Integer> queue,
124 int expected) {
125 if (debug) {
126 System.out.println("Reading the queue");
127 }
128
129 // Empty the queue and record numbers into a[];
130 NumberedWeakReference weakRead = waitForReference(queue);
131 int length = 0;
132 while (weakRead != null) {
133 a[length++] = weakRead.number;
134 if (length < expected) {
135 weakRead = waitForReference(queue);
136 } else { // Check for unexpected extra entries.
137 weakRead = (NumberedWeakReference) queue.poll();
138 }
139 }
140 if (debug) {
141 System.out.println("Reference Queue had " + length + " elements");
142 }
143
144
145 // verify the queued references: all but the last Reference object
146 // should have been in the queue.
147 if (debug) {
148 System.out.println("Start of final check");
149 }
150
151 // Sort the first "length" elements in array "a[]".
152 sort(length);
153
154 boolean fail = (length != expected);
155 for (int i = 0; i < length; i++) {
156 if (a[i] != i) {
157 if (debug) {
158 System.out.println("a[" + i + "] is not " + i + " but " + a[i]);
159 }
160 fail = true;
161 }
162 }
163 if (fail) {
164 printMissingElements(length, expected);
165 throw new RuntimeException("TEST FAILED: only " + length
166 + " reference objects have been queued out of "
167 + expected);
168 }
169 }
170
171 private static void printMissingElements(int length, int expected) {
172 System.out.println("The following numbers were not found in the reference queue: ");
174 int element = 0;
175 for (int i = 0; i < length; i++) {
176 while ((a[i] != element) & (element < expected)) {
177 System.out.print(element + " ");
178 if (missing % 20 == 19) {
179 System.out.println(" ");
180 }
181 missing++;
182 element++;
183 }
184 element++;
185 }
186 System.out.print("\n");
187 }
188
189 private static void forceGc(long millis) throws InterruptedException {
190 Runtime.getRuntime().gc();
191 Thread.sleep(millis);
192 }
193
194 // Bubble sort the first "length" elements in array "a".
195 private static void sort(int length) {
196 int hold;
197 if (debug) {
198 System.out.println("Sorting. Length=" + length);
199 }
200 for (int pass = 1; pass < length; pass++) { // passes over the array
201 for (int i = 0; i < length - pass; i++) { // a single pass
202 if (a[i] > a[i + 1]) { // then swap
203 hold = a[i];
204 a[i] = a[i + 1];
205 a[i + 1] = hold;
206 }
207 } // End of i loop
208 } // End of pass loop
209 }
210
211 // Raise thread priority so as to increase the
212 // probability of the mutator succeeding in enqueueing
213 // an object that is still in the pending state.
214 // This is (probably) only required for a uniprocessor.
215 static void raisePriority() {
216 Thread tr = Thread.currentThread();
217 tr.setPriority(Thread.MAX_PRIORITY);
218 }
219 } // End of class ReferenceEnqueuePending
|
1 /*
2 * Copyright (c) 2011, 2024, 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 /* @test
25 * @bug 4243978 8336671
26 * @summary Test if Reference.enqueue() works properly with pending references
27 */
28 import java.lang.ref.*;
29 import java.util.Arrays;
30
31 public class ReferenceEnqueuePending {
32
33 record Numbered(int number) {}
34
35 static class NumberedWeakReference extends WeakReference<Numbered> {
36 // Add an integer to identify the weak reference object.
37 int number;
38
39 NumberedWeakReference(Numbered referent, ReferenceQueue<Numbered> q, int i) {
40 super(referent, q);
41 number = i;
42 }
43 }
44
45 static final boolean debug = System.getProperty("test.debug") != null;
46 static final int iterations = 1000;
47 static final int gc_trigger = 99;
48 static int[] a = new int[2 * iterations];
49 // Keep all weak references alive with the following array.
50 static NumberedWeakReference[] b = new NumberedWeakReference[iterations];
51
52 public static void main(String[] argv) throws Exception {
53 if (debug) {
54 System.out.println("Starting the test.");
55 }
56 // Raise thread priority to match the referenceHandler
57 // priority, so that they can race also on a uniprocessor.
58 raisePriority();
59
60 ReferenceQueue<Numbered> refQueue = new ReferenceQueue<>();
61
62 // Our objective is to let the mutator enqueue
63 // a Reference object that may already be in the
64 // pending state because of having been identified
65 // as weakly reachable at a previous garbage collection.
66 // To this end, we create many Reference objects, each with
67 // a unique Numbered object as its referant.
68 // We let the referents become eligible for collection,
69 // while racing with the garbage collector which may
70 // have pended some of these Reference objects.
71 // Finally, we check that all of the Reference objects
72 // end up on their queue. The test was originally
73 // submitted to show that such races could break the
74 // pending list and/or the reference queue, because of sharing
75 // the same link ("next") for maintaining both lists, thus
76 // losing some of the Reference objects on either queue.
77
78 Numbered obj = new Numbered(0);
79 NumberedWeakReference weaky = new NumberedWeakReference(obj, refQueue, 0);
80 for (int i = 1; i < iterations; i++) {
81 // Create a new object, dropping the only strong reference to
82 // the previous Numbered object.
83 obj = new Numbered(i);
84 // Trigger gc each gc_trigger iterations.
85 if ((i % gc_trigger) == 0) {
86 forceGc(0);
87 }
88 // Enqueue every other weaky.
89 if ((i % 2) == 0) {
90 weaky.enqueue();
91 }
92 // Remember the Reference objects, for testing later.
93 b[i - 1] = weaky;
94 // Get a new weaky for the Numbered object just
95 // created, which may be explicitly enqueued in
96 // our next trip around the loop.
97 weaky = new NumberedWeakReference(obj, refQueue, i);
98 }
99
100 // Do a final collection to discover and process all
101 // Reference objects created above, allowing some time
102 // for the ReferenceHandler thread to queue the References.
103 forceGc(100);
104 forceGc(100);
105
106 // Verify that all WeakReference objects ended up queued.
107 checkResult(refQueue, iterations-1);
108
109 // Ensure the final weaky is live but won't be enqueued during
110 // result checking, by ensuring its referent remains live.
111 // This eliminates behavior changes resulting from different
112 // compiler optimizations.
113 Reference.reachabilityFence(weaky);
114 Reference.reachabilityFence(obj);
115
116 System.out.println("Test passed.");
117 }
118
119 private static NumberedWeakReference waitForReference(ReferenceQueue<Numbered> queue) {
120 try {
121 return (NumberedWeakReference) queue.remove(30000); // 30sec
122 } catch (InterruptedException ie) {
123 return null;
124 }
125 }
126
127 private static void checkResult(ReferenceQueue<Numbered> queue,
128 int expected) {
129 if (debug) {
130 System.out.println("Reading the queue");
131 }
132
133 // Empty the queue and record numbers into a[];
134 NumberedWeakReference weakRead = waitForReference(queue);
135 int length = 0;
136 while (weakRead != null) {
137 a[length++] = weakRead.number;
138 if (length < expected) {
139 weakRead = waitForReference(queue);
140 } else { // Check for unexpected extra entries.
141 weakRead = (NumberedWeakReference) queue.poll();
142 }
143 }
144 if (debug) {
145 System.out.println("Reference Queue had " + length + " elements");
146 }
147
148
149 // verify the queued references: all but the last Reference object
150 // should have been in the queue.
151 if (debug) {
152 System.out.println("Start of final check");
153 }
154
155 // Sort the first "length" elements in array "a[]".
156 Arrays.sort(a, 0, length);
157
158 boolean fail = (length != expected);
159 for (int i = 0; i < length; i++) {
160 if (a[i] != i) {
161 if (debug) {
162 System.out.println("a[" + i + "] is not " + i + " but " + a[i]);
163 }
164 fail = true;
165 }
166 }
167 if (fail) {
168 printMissingElements(length, expected);
169 throw new RuntimeException("TEST FAILED: only " + length
170 + " reference objects have been queued out of "
171 + expected);
172 }
173 }
174
175 private static void printMissingElements(int length, int expected) {
176 System.out.println("The following numbers were not found in the reference queue: ");
178 int element = 0;
179 for (int i = 0; i < length; i++) {
180 while ((a[i] != element) & (element < expected)) {
181 System.out.print(element + " ");
182 if (missing % 20 == 19) {
183 System.out.println(" ");
184 }
185 missing++;
186 element++;
187 }
188 element++;
189 }
190 System.out.print("\n");
191 }
192
193 private static void forceGc(long millis) throws InterruptedException {
194 Runtime.getRuntime().gc();
195 Thread.sleep(millis);
196 }
197
198 // Raise thread priority so as to increase the
199 // probability of the mutator succeeding in enqueueing
200 // an object that is still in the pending state.
201 // This is (probably) only required for a uniprocessor.
202 static void raisePriority() {
203 Thread tr = Thread.currentThread();
204 tr.setPriority(Thread.MAX_PRIORITY);
205 }
206 } // End of class ReferenceEnqueuePending
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