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/*
* Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/**
* @test
* @bug 8284161 8286788
* @summary Test that a carrier thread waits on a virtual thread
* @requires vm.continuations
* @modules java.base/java.lang:+open
* @run junit CarrierThreadWaits
*/
/**
* @test
* @requires vm.continuations & vm.debug
* @modules java.base/java.lang:+open
* @run junit/othervm -XX:+UnlockExperimentalVMOptions -XX:LockingMode=0 CarrierThreadWaits
*/
import java.lang.management.LockInfo;
import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.util.concurrent.Executor;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class CarrierThreadWaits {
@Test
void testCarrierThreadWaiting() throws Exception {
try (ForkJoinPool pool = new ForkJoinPool(1)) {
var carrierRef = new AtomicReference<Thread>();
var vthreadRef = new AtomicReference<Thread>();
Executor scheduler = task -> {
pool.submit(() -> {
Thread carrier = Thread.currentThread();
carrierRef.set(carrier);
Thread vthread = vthreadRef.get();
System.err.format("%s run task (%s) ...%n", carrier, vthread);
task.run();
System.err.format("%s task done (%s)%n", carrier, vthread);
});
};
// start a virtual thread that spins and remains mounted until "done"
var started = new AtomicBoolean();
var done = new AtomicBoolean();
Thread.Builder builder = ThreadBuilders.virtualThreadBuilder(scheduler);
Thread vthread = builder.unstarted(() -> {
started.set(true);
while (!done.get()) {
Thread.onSpinWait();
}
});
vthreadRef.set(vthread);
vthread.start();
try {
// wait for virtual thread to start
while (!started.get()) {
Thread.sleep(10);
}
Thread carrier = carrierRef.get();
long carrierId = carrier.threadId();
long vthreadId = vthread.threadId();
// carrier thread should be on WAITING on virtual thread
ThreadInfo ti = ManagementFactory.getThreadMXBean().getThreadInfo(carrierId);
Thread.State state = ti.getThreadState();
LockInfo lockInfo = ti.getLockInfo();
assertEquals(Thread.State.WAITING, state);
assertNotNull(lockInfo);
assertEquals(vthread.getClass().getName(), lockInfo.getClassName());
assertEquals(System.identityHashCode(vthread), lockInfo.getIdentityHashCode());
assertEquals(vthreadId, ti.getLockOwnerId());
} finally {
done.set(true);
}
}
}
}
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