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/*
* Copyright (C) 2021 THL A29 Limited, a Tencent company. 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
* @summary Test virtual thread park when scheduler is a fixed thread pool
* @requires vm.continuations
* @modules java.base/java.lang:+open
* @library /test/lib
* @run main ParkWithFixedThreadPool
*/
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.locks.LockSupport;
import jdk.test.lib.thread.VThreadScheduler;
public class ParkWithFixedThreadPool {
public static void main(String[] args) throws Exception {
try (var scheduler = new Scheduler(8)) {
int vthreadCount = 300;
Thread[] vthreads = new Thread[vthreadCount];
Runnable target = new Runnable() {
public void run() {
int myIndex = -1;
for (int i = 0; i < vthreadCount; i++) {
if (vthreads[i] == Thread.currentThread()) {
myIndex = i;
break;
}
}
if (myIndex > 0) {
LockSupport.unpark(vthreads[myIndex - 1]);
}
if (myIndex != (vthreadCount - 1)) {
LockSupport.park();
}
}
};
ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
for (int i = 0; i < vthreadCount; i++) {
vthreads[i] = factory.newThread(target);
}
for (int i = 0; i < vthreadCount; i++) {
vthreads[i].start();
}
for (int i = 0; i < vthreadCount; i++) {
vthreads[i].join();
}
}
}
static class Scheduler implements Executor, AutoCloseable {
private final ExecutorService pool;
Scheduler(int poolSize) {
pool = Executors.newFixedThreadPool(poolSize);
}
@Override
public void execute(Runnable task) {
try {
pool.execute(task);
} finally {
// ExecutorService::execute may consume parking permit
LockSupport.unpark(Thread.currentThread());
}
}
@Override
public void close() {
pool.close();
}
}
}
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