1 /*
2 * Copyright (c) 2022, 2023, 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 8284161 8286788
27 * @summary Test that a carrier thread waits on a virtual thread
28 * @requires vm.continuations
29 * @modules java.base/java.lang:+open
30 * @run junit CarrierThreadWaits
31 */
32
33 /**
34 * @test
35 * @requires vm.continuations & vm.debug
36 * @modules java.base/java.lang:+open
37 * @run junit/othervm -XX:LockingMode=0 CarrierThreadWaits
38 */
39
40 import java.lang.management.LockInfo;
41 import java.lang.management.ManagementFactory;
42 import java.lang.management.ThreadInfo;
43 import java.util.concurrent.Executor;
44 import java.util.concurrent.ForkJoinPool;
45 import java.util.concurrent.atomic.AtomicBoolean;
46 import java.util.concurrent.atomic.AtomicReference;
47
48 import org.junit.jupiter.api.Test;
49 import static org.junit.jupiter.api.Assertions.*;
50
51 class CarrierThreadWaits {
52
53 @Test
54 void testCarrierThreadWaiting() throws Exception {
55 try (ForkJoinPool pool = new ForkJoinPool(1)) {
56 var carrierRef = new AtomicReference<Thread>();
57 var vthreadRef = new AtomicReference<Thread>();
58
59 Executor scheduler = task -> {
60 pool.submit(() -> {
61 Thread carrier = Thread.currentThread();
62 carrierRef.set(carrier);
63 Thread vthread = vthreadRef.get();
64
65 System.err.format("%s run task (%s) ...%n", carrier, vthread);
66 task.run();
67 System.err.format("%s task done (%s)%n", carrier, vthread);
68 });
69 };
70
71 // start a virtual thread that spins and remains mounted until "done"
72 var started = new AtomicBoolean();
73 var done = new AtomicBoolean();
74 Thread.Builder builder = ThreadBuilders.virtualThreadBuilder(scheduler);
75 Thread vthread = builder.unstarted(() -> {
76 started.set(true);
77 while (!done.get()) {
78 Thread.onSpinWait();
79 }
80 });
81 vthreadRef.set(vthread);
82 vthread.start();
83
84 try {
85 // wait for virtual thread to start
86 while (!started.get()) {
87 Thread.sleep(10);
88 }
89
90 Thread carrier = carrierRef.get();
91
92 long carrierId = carrier.threadId();
93 long vthreadId = vthread.threadId();
94
95 // carrier thread should be on WAITING on virtual thread
96 ThreadInfo ti = ManagementFactory.getThreadMXBean().getThreadInfo(carrierId);
97 Thread.State state = ti.getThreadState();
98 LockInfo lockInfo = ti.getLockInfo();
99 assertEquals(Thread.State.WAITING, state);
100 assertNotNull(lockInfo);
101 assertEquals(vthread.getClass().getName(), lockInfo.getClassName());
102 assertEquals(System.identityHashCode(vthread), lockInfo.getIdentityHashCode());
103 assertEquals(vthreadId, ti.getLockOwnerId());
104 } finally {
105 done.set(true);
106 }
107 }
108 }
109
110 }