1 /*
2 * Copyright (c) 2017, 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 * @test
26 * @bug 8059022
27 * @modules java.base/jdk.internal.misc:+open
28 * @summary Validate barriers after Unsafe getObject, CAS and swap (GetAndSet)
29 * @run main/othervm -XX:+UseZGC -XX:+ZUnmapBadViews -XX:ZCollectionInterval=1 -XX:-CreateCoredumpOnCrash -XX:CompileCommand=dontinline,*::mergeImpl* compiler.gcbarriers.UnsafeIntrinsicsTest
30 */
31
32 package compiler.gcbarriers;
33
34 import java.lang.reflect.Field;
35 import java.util.ArrayList;
36 import java.util.Random;
37 import sun.misc.Unsafe;
38
39 public class UnsafeIntrinsicsTest {
40
41 /*
42 * This test triggers the loadbarriers by allocating a lot, keeping the objects alive and then
43 * letting them die in a way that maximizes fragmentation.
44 *
45 * All subtests (OperationType's) could run in parallel.
46 */
47
48 static int node_count = 133700;
49 static int thread_count = 4;
50 static int time = Integer.getInteger("time", 4); // seconds per subtest
51
52 static Runner r = new Runner(null, 1, 1, Runner.OperationType.CAS);
53
54 static Node first_node;
55 int epoch = 0;
56
57 public static void main(String[] args) {
58 UnsafeIntrinsicsTest t = new UnsafeIntrinsicsTest();
59
60 t.testWithLocalData(Runner.OperationType.CAS);
61 t.testWithLocalData(Runner.OperationType.Weak_CAS);
62 t.testWithLocalData(Runner.OperationType.CMPX);
63
64 t.testWithSharedData(Runner.OperationType.Swap);
65 t.testWithSharedData(Runner.OperationType.Load);
66 }
67
68 public UnsafeIntrinsicsTest() {
69
70 }
71
72 public void testWithLocalData(Runner.OperationType optype) {
73 System.out.println("Testing " + optype.name() + " with " + thread_count +" thread and " + node_count + " nodes");
74
75 // start mutator threads
76 ArrayList<Thread> thread_list = new ArrayList<Thread>();
77 Random r = new Random(System.nanoTime());
78 for (int i = 0; i < thread_count; i++) {
79
80 setup(); // each thread has its own circle of nodes
81 Thread t = new Thread(new Runner(first_node, time, r.nextLong(), optype));
82 t.start();
83 thread_list.add(t);
84 }
85
86 waitForCompletion(thread_list);
87 countNodes();
88 }
89
90 public void testWithSharedData(Runner.OperationType optype) {
91 System.out.println("Testing " + optype.name() + " with " + thread_count +" thread and " + node_count + " nodes");
92
93 setup(); // All nodes are shared between threads
94 ArrayList<Thread> thread_list = new ArrayList<Thread>();
95 Random r = new Random(System.nanoTime());
96 for (int i = 0; i < thread_count; i++) {
97 Thread t = new Thread(new Runner(first_node, time, r.nextLong(), optype));
98 t.start();
99 thread_list.add(t);
100 }
101
102 waitForCompletion(thread_list);
103 countNodes();
104 }
105
106 public void waitForCompletion(ArrayList<Thread> thread_list) {
107 // do some waiting
108 try {
109 Thread.sleep(time*1000);
110 } catch (InterruptedException e) {
111 e.printStackTrace();
112 }
113
114 // wait for all thread to terminate
115 for (int i = 0; i < thread_count; i++) {
116 try {
117 thread_list.get(i).join();
118 } catch (InterruptedException e) {
119 e.printStackTrace();
120 }
121 }
122 }
123
124 void countNodes() {
125 epoch++;
126 int count = 0;
127 Node node = first_node;
128 while (node.number() < epoch) {
129 node.setNumber(epoch);
130 count++;
131 node = node.next();
132 }
133 System.out.println("Program end, found " + count + " nodes");
134 }
135
136 // Create a circular linked list
137 public void setup() {
138 first_node = new Node();
139 Node last_node = first_node;
140 for (int i = 0; i < node_count; i++) {
141 last_node = new Node(last_node);
142 }
143 first_node.setNext(last_node);
144 }
145 }
146
147 class Runner implements Runnable {
148
149 OperationType type;
150 Node current;
151 Random r;
152 long time;
153 long seed;
154
155 long milage = 0;
156 long created = 0;
157 long skipped = 0;
158 int iterations = 0;
159
160 static final jdk.internal.misc.Unsafe UNSAFE;
161 static final long offset;
162
163 public enum OperationType {
164 Load("Load"),
165 Swap("Swap"),
166 CAS("CAS"),
167 Weak_CAS("Weak-CAS"),
168 CMPX("CMPX");
169
170 private String name;
171 private OperationType(String name) { this.name = name; }
172 }
173
174 static {
175 try {
176 Field f = jdk.internal.misc.Unsafe.class.getDeclaredField("theUnsafe");
177 f.setAccessible(true);
178 UNSAFE = (jdk.internal.misc.Unsafe) f.get(null);
179 offset = UNSAFE.objectFieldOffset(Node.class.getDeclaredField("next"));
180 } catch (Exception e) {
181 throw new RuntimeException("Unable to get Unsafe instance.", e);
182 }
183 }
184
185 public Runner(Node start, int testtime, long seed, OperationType type) {
186 current = start;
187 time = testtime*1000000000L;
188 r = new Random(seed);
189 this.type = type;
190 }
191
192 @Override
193 public void run() {
194 long starttime = System.nanoTime();
195 while((System.nanoTime() - starttime) < time) {
196 iterations++;
197 // Run a bit
198 int run_length = r.nextInt() & 0xfff;
199 for (int i = 0; i < run_length; i++) {
200 current = current.next();
201 milage++;
202 }
203 // find a start node
204 Node startNode = current;
205 Node expectedNext = startNode.next;
206
207 // Run a bit more
208 int skip_length = (r.nextInt() & 0xff) + 1;
209 for (int i = 0; i < skip_length; i++) {
210 current = current.next();
211 skipped++;
212 }
213
214 // create a branch
215 int branch_length = (r.nextInt() & 0xff) + 1;
216 created += branch_length;
217 Node head = makeBranch(current, branch_length);
218
219 // complete circle, but continue to run on old path
220 boolean test_fail = ((iterations & 0x1) == 0);
221 Node current = merge(startNode, expectedNext, head, test_fail);
222 }
223 System.out.println("Milage: " + milage + " Skipped: " + skipped + " Created: " + created + " iterations: " + iterations);
224 }
225
226 /*
227 * The reason for the duplicated code that is wrapping the unsafe operations is that we want
228 * to test the operations individually. They must not interfere with each other - checking a field
229 * will heal that reference and no operation after can trigger the barrier.
230 *
231 * All mergeImpl*-method are prevented from being inlined.
232 */
233
234 private Node merge(Node startNode, Node expectedNext, Node head, boolean test_fail) {
235 switch (type) {
236 case Load:
237 return mergeImplLoad(startNode, expectedNext, head);
238 case Swap:
239 return mergeImplSwap(startNode, expectedNext, head);
240 case CAS:
241 if (test_fail) {
242 return mergeImplCASFail(startNode, expectedNext, head);
243 } else {
244 return mergeImplCAS(startNode, expectedNext, head);
245 }
246 case Weak_CAS:
247 if (test_fail) {
248 return mergeImplWeakCASFail(startNode, expectedNext, head);
249 } else {
250 return mergeImplWeakCAS(startNode, expectedNext, head);
251 }
252 case CMPX:
253 if (test_fail) {
254 return mergeImplCMPXFail(startNode, expectedNext, head);
255 } else {
256 return mergeImplCMPX(startNode, expectedNext, head);
257 }
258 default:
259 throw new Error("Unimplemented");
260 }
261 }
262
263 private Node mergeImplLoad(Node startNode, Node expectedNext, Node head) {
264 // Atomic load version
265 Node temp = (Node) UNSAFE.getObject(startNode, offset);
266 startNode.setNext(head);
267 return temp;
268 }
269
270 private Node mergeImplSwap(Node startNode, Node expectedNext, Node head) {
271 // Swap version
272 return (Node) UNSAFE.getAndSetObject(startNode, offset, head);
273 }
274
275 private Node mergeImplCAS(Node startNode, Node expectedNext, Node head) {
276 // CAS - should always be true within a single thread - no other thread can have overwritten
277 if (!UNSAFE.compareAndSwapObject(startNode, offset, expectedNext, head)) {
278 throw new Error("CAS should always succeed on thread local objects, check you barrier implementation");
279 }
280 return expectedNext; // continue on old circle
281 }
282
283 private Node mergeImplCASFail(Node startNode, Node expectedNext, Node head) {
284 // Force a fail
285 if (UNSAFE.compareAndSwapObject(startNode, offset, "fail", head)) {
286 throw new Error("This CAS should always fail, check you barrier implementation");
287 }
288 if (startNode.next() != expectedNext) {
289 throw new Error("Shouldn't have changed");
290 }
291 return current;
292 }
293
294 private Node mergeImplWeakCAS(Node startNode, Node expectedNext, Node head) {
295 // Weak CAS - should always be true within a single thread - no other thread can have overwritten
296 if (!UNSAFE.weakCompareAndSwapObject(startNode, offset, expectedNext, head)) {
297 throw new Error("Weak CAS should always succeed on thread local objects, check you barrier implementation");
298 }
299 return expectedNext; // continue on old circle
300 }
301
302 private Node mergeImplWeakCASFail(Node startNode, Node expectedNext, Node head) {
303 // Force a fail
304 if (UNSAFE.weakCompareAndSwapObject(startNode, offset, "fail", head)) {
305 throw new Error("This weak CAS should always fail, check you barrier implementation");
306 }
307 if (startNode.next() != expectedNext) {
308 throw new Error("Shouldn't have changed");
309 }
310 return current;
311 }
312
313 private Node mergeImplCMPX(Node startNode, Node expectedNext, Node head) {
314 // CmpX - should always be true within a single thread - no other thread can have overwritten
315 Object res = UNSAFE.compareAndExchangeObjectVolatile(startNode, offset, expectedNext, head);
316 if (!res.equals(expectedNext)) {
317 throw new Error("Fail CmpX should always succeed on thread local objects, check you barrier implementation");
318 }
319 return expectedNext; // continue on old circle
320 }
321
322 private Node mergeImplCMPXFail(Node startNode, Node expectedNext, Node head) {
323 Object res = UNSAFE.compareAndExchangeObjectVolatile(startNode, offset, head, head);
324 if (startNode.next() != expectedNext) {
325 throw new Error("Shouldn't have changed");
326 }
327 if (head == expectedNext) {
328 throw new Error("Test malfunction");
329 }
330 if (!res.equals(expectedNext)) {
331 throw new Error("This CmpX should have returned 'expectedNext' when it failed");
332 }
333 if (res.equals(head)) {
334 throw new Error("This CmpX shouldn't have returned head when it failed. count: "+ iterations);
335 }
336
337 return current;
338 }
339
340 // Create a new branch that will replace a part of the circle
341 public Node makeBranch(Node end_node, int count) {
342 Node head = end_node;
343 for (int i = 0; i < count; i++) {
344 head = new Node(head);
345 }
346 return head;
347 }
348 }
349
350 class Node {
351 Node next;
352 int number = 0;
353
354 public int number() {
355 return number;
356 }
357
358 public void setNumber(int v) {
359 number = v;
360 }
361
362 public Node() {
363 }
364
365 public Node(Node link) {
366 next = link;
367 }
368
369 public void setNext(Node next) {
370 this.next = next;
371 }
372 public Node next() {
373 return next;
374 }
375 }