1 /*
   2  * Copyright (c) 2016, 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 /*
  26  * @test HandshakeWalkStackTest
  27  * @library /testlibrary /test/lib
  28  * @build HandshakeWalkStackTest
  29  * @run main ClassFileInstaller sun.hotspot.WhiteBox
  30  *                              sun.hotspot.WhiteBox$WhiteBoxPermission
  31  * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeWalkStackTest
  32  */
  33 
  34 import jdk.test.lib.Asserts;
  35 import sun.hotspot.WhiteBox;
  36 
  37 public class HandshakeWalkStackTest {
  38 
  39     public static void main(String... args) throws Exception {
  40         int iterations = 3;
  41         if (args.length > 0) {
  42             iterations = Integer.parseInt(args[0]);
  43         }
  44         test(iterations);
  45     }
  46 
  47     private static void test(int iterations) throws Exception {
  48         Thread loop_thread  = new Thread(() -> run_loop(create_list()));
  49         Thread alloc_thread = new Thread(() -> run_alloc());
  50         Thread wait_thread  = new Thread(() -> run_wait(new Object() {}));
  51         loop_thread.start();
  52         alloc_thread.start();
  53         wait_thread.start();
  54 
  55         WhiteBox wb = WhiteBox.getWhiteBox();
  56         int walked = 0;
  57         for (int i = 0; i < iterations; i++) {
  58             System.out.println("Iteration " + i);
  59             System.out.flush();
  60             Thread.sleep(200);
  61             walked = wb.handshakeWalkStack(loop_thread, false);
  62             Asserts.assertEQ(walked, 1, "Must have walked one thread stack");
  63             Thread.sleep(200);
  64             walked = wb.handshakeWalkStack(alloc_thread, false);
  65             Asserts.assertEQ(walked, 1, "Must have walked one thread stack");
  66             Thread.sleep(200);
  67             walked = wb.handshakeWalkStack(wait_thread, false);
  68             Asserts.assertEQ(walked, 1, "Must have walked one thread stack");
  69             Thread.sleep(200);
  70             walked = wb.handshakeWalkStack(Thread.currentThread(), false);
  71             Asserts.assertEQ(walked, 1, "Must have walked one thread stack");
  72         }
  73         Thread.sleep(200);
  74         walked = wb.handshakeWalkStack(null, true);
  75         Asserts.assertGT(walked, 4, "Must have walked more than three thread stacks");
  76     }
  77 
  78     static class List {
  79         List next;
  80 
  81         List(List next) {
  82             this.next = next;
  83         }
  84     }
  85 
  86     public static List create_list() {
  87         List head = new List(null);
  88         List elem = new List(head);
  89         List elem2 = new List(elem);
  90         List elem3 = new List(elem2);
  91         List elem4 = new List(elem3);
  92         head.next = elem4;
  93 
  94         return head;
  95     }
  96 
  97     public static void run_loop(List loop) {
  98         while (loop.next != null) {
  99             loop = loop.next;
 100         }
 101     }
 102 
 103     public static byte[] array;
 104 
 105     public static void run_alloc() {
 106         while (true) {
 107             // Write to public static to ensure the byte array escapes.
 108             array = new byte[4096];
 109         }
 110     }
 111 
 112     public static void run_wait(Object lock) {
 113         synchronized (lock) {
 114             try {
 115                 lock.wait();
 116             } catch (InterruptedException ie) {}
 117         }
 118     }
 119 }