1 /*
   2  * Copyright (c) 2014, 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 WBStackSize
  26  * @summary verify that whitebox functions getThreadFullStackSize() and getThreadRemainingStackSize are working
  27  * @library /testlibrary /testlibrary/whitebox
  28  * @build WBStackSize
  29  * @run main ClassFileInstaller sun.hotspot.WhiteBox
  30  * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xss512k WBStackSize 
  31  */
  32 
  33 import com.sun.management.HotSpotDiagnosticMXBean;
  34 import sun.hotspot.WhiteBox;
  35 
  36 public class WBStackSize {
  37 
  38     static final long K = 1024;
  39 
  40     static final long MIN_STACK_SIZE = 8 * K;
  41     static final long MAX_STACK_SIZE_ALLOCATED_IN_MAIN = 200 * K; // current value is about 130k on 64-bit platforms
  42 
  43     static final WhiteBox wb = WhiteBox.getWhiteBox();
  44 
  45     static long stackSizeOnOverflow = -1;
  46 
  47     static int eatAllStack() {
  48         return eatAllStack() * 2;
  49     }
  50     
  51     static void testStackOverflow() {
  52 
  53         stackSizeOnOverflow = wb.getThreadRemainingStackSize();
  54 
  55         if (stackSizeOnOverflow > MIN_STACK_SIZE) {
  56 
  57             try {
  58                 testStackOverflow();
  59             } catch (StackOverflowError e) {
  60                 // We caught SOE too early. The error will be reported in main()
  61             }
  62 
  63         } else {
  64 
  65             try {
  66                 eatAllStack();
  67                 throw new RuntimeException("Haven't caught StackOverflowError at all");
  68             } catch (StackOverflowError e) {
  69                 // OK: we caught the anticipated error
  70             }
  71         }
  72     }
  73 
  74     public static void main(String[] args) {
  75         HotSpotDiagnosticMXBean bean = sun.management.ManagementFactoryHelper.getDiagnosticMXBean();
  76         long configStackSize = Long.valueOf(bean.getVMOption("ThreadStackSize").getValue()) * K;
  77 
  78         System.out.println("ThreadStackSize VM option: " + configStackSize);
  79 
  80         long actualStackSize = wb.getThreadFullStackSize();
  81         System.out.println("Full stack size: " + actualStackSize);
  82 
  83         if (Math.abs(actualStackSize - configStackSize) > configStackSize * 0.1) {
  84             throw new RuntimeException("getThreadFullStackSize value [" + actualStackSize 
  85                                      + "] should be within 90%..110% of the value returned by HotSpotDiagnosticMXBean");
  86         }
  87 
  88         long remainingStackSize = wb.getThreadRemainingStackSize();
  89         System.out.println("Remaining stack size in main(): " + remainingStackSize);
  90         
  91         // Up to 200k can be already allocated by VM
  92         if (remainingStackSize > configStackSize 
  93                 || (configStackSize > MAX_STACK_SIZE_ALLOCATED_IN_MAIN 
  94                 && remainingStackSize < configStackSize - MAX_STACK_SIZE_ALLOCATED_IN_MAIN)) {
  95 
  96             throw new RuntimeException("getThreadRemainingStackSize value [" + remainingStackSize 
  97                                      + "] should be at least ThreadStackSize value [" + configStackSize + "] minus [" 
  98                                      + MAX_STACK_SIZE_ALLOCATED_IN_MAIN + "]");
  99         }
 100 
 101         testStackOverflow();
 102 
 103         if (stackSizeOnOverflow > MIN_STACK_SIZE) {
 104             throw new RuntimeException("Caught StackOverflowError too early: when there were " 
 105                                      + stackSizeOnOverflow + " bytes in stack");
 106         } else if (stackSizeOnOverflow < 0) {
 107             throw new RuntimeException("Internal test error: stackRemainingSize < 0");
 108         } else {
 109             System.out.println("Caught StackOverflowError as expected");
 110         }
 111     }
 112 }