1 /* 2 * Copyright (c) 2018, 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 /* 26 * @test HandshakeWalkSuspendExitTest 27 * @summary This test tries to stress the handshakes with new and exiting threads while suspending them. 28 * @library /testlibrary /test/lib 29 * @build HandshakeWalkSuspendExitTest 30 * @run driver ClassFileInstaller sun.hotspot.WhiteBox 31 * sun.hotspot.WhiteBox$WhiteBoxPermission 32 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeWalkSuspendExitTest 33 */ 34 35 import jdk.test.lib.Asserts; 36 import sun.hotspot.WhiteBox; 37 38 public class HandshakeWalkSuspendExitTest implements Runnable { 39 40 static final int _test_threads = 8; 41 static final int _test_exit_threads = 128; 42 static Thread[] _threads = new Thread[_test_threads]; 43 static volatile boolean exit_now = false; 44 static java.util.concurrent.Semaphore _sem = new java.util.concurrent.Semaphore(0); 45 46 @Override 47 public void run() { 48 WhiteBox wb = WhiteBox.getWhiteBox(); 49 while (!exit_now) { 50 _sem.release(); 51 // We only suspend threads on even index and not ourself. 52 // Otherwise we can accidentially suspend all threads. 53 for (int i = 0; i < _threads.length; i += 2) { 54 wb.handshakeWalkStack(null /* ignored */, true /* stackwalk all threads */); 55 if (Thread.currentThread() != _threads[i]) { 56 _threads[i].suspend(); 57 _threads[i].resume(); 58 } 59 } 60 for (int i = 0; i < _threads.length; i += 2) { 61 wb.handshakeWalkStack(_threads[i] /* thread to stackwalk */, false /* stackwalk one thread */); 62 if (Thread.currentThread() != _threads[i]) { 63 _threads[i].suspend(); 64 _threads[i].resume(); 65 } 66 } 67 } 68 } 69 70 public static void main(String... args) throws Exception { 71 HandshakeWalkSuspendExitTest test = new HandshakeWalkSuspendExitTest(); 72 73 for (int i = 0; i < _threads.length; i++) { 74 _threads[i] = new Thread(test); 75 _threads[i].start(); 76 } 77 for (int i = 0; i < _test_threads; i++) { 78 _sem.acquire(); 79 } 80 Thread[] exit_threads = new Thread[_test_exit_threads]; 81 for (int i = 0; i < _test_exit_threads; i++) { 82 exit_threads[i] = new Thread(new Runnable() { public void run() {} }); 83 exit_threads[i].start(); 84 } 85 exit_now = true; 86 for (int i = 0; i < _threads.length; i++) { 87 _threads[i].join(); 88 } 89 for (int i = 0; i < exit_threads.length; i++) { 90 exit_threads[i].join(); 91 } 92 } 93 }