1 /*
   2  * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 /**
  25  * @test TestMemoryMXBeans
  26  * @key gc
  27  * @requires vm.gc.Epsilon
  28  * @summary Test JMX memory beans
  29  * @modules java.base/jdk.internal.misc
  30  *          java.management
  31  * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC          -Xmx1g TestMemoryMXBeans   -1 1024
  32  * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xms1g   -Xmx1g TestMemoryMXBeans 1024 1024
  33  * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -Xms128m -Xmx1g TestMemoryMXBeans  128 1024
  34  */
  35 
  36 import java.lang.management.*;
  37 import java.util.*;
  38 
  39 public class TestMemoryMXBeans {
  40 
  41     static volatile Object sink;
  42 
  43     public static void main(String[] args) throws Exception {
  44         if (args.length < 2) {
  45             throw new IllegalStateException("Should provide expected heap sizes");
  46         }
  47 
  48         long initSize = 1L * Integer.parseInt(args[0]) * 1024 * 1024;
  49         long maxSize =  1L * Integer.parseInt(args[1]) * 1024 * 1024;
  50 
  51         testMemoryBean(initSize, maxSize);
  52         testAllocs();
  53     }
  54 
  55     public static void testMemoryBean(long initSize, long maxSize) {
  56         MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();
  57         long heapInit = memoryMXBean.getHeapMemoryUsage().getInit();
  58         long heapMax = memoryMXBean.getHeapMemoryUsage().getMax();
  59         long nonHeapInit = memoryMXBean.getNonHeapMemoryUsage().getInit();
  60         long nonHeapMax = memoryMXBean.getNonHeapMemoryUsage().getMax();
  61 
  62         if (initSize > 0 && heapInit != initSize) {
  63             throw new IllegalStateException("Init heap size is wrong: " + heapInit + " vs " + initSize);
  64         }
  65         if (maxSize > 0 && heapMax != maxSize) {
  66             throw new IllegalStateException("Max heap size is wrong: " + heapMax + " vs " + maxSize);
  67         }
  68     }
  69 
  70     public static void testAllocs() {
  71         MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();
  72 
  73         // Do lazy inits first:
  74         long heapUsed1 = memoryMXBean.getHeapMemoryUsage().getUsed();
  75         sink = new int[1024*1024];
  76         long heapUsed2 = memoryMXBean.getHeapMemoryUsage().getUsed();
  77 
  78         // Compute how much we waste during the calls themselves:
  79         heapUsed1 = memoryMXBean.getHeapMemoryUsage().getUsed();
  80         heapUsed2 = memoryMXBean.getHeapMemoryUsage().getUsed();
  81         long adj = heapUsed2 - heapUsed1;
  82 
  83         heapUsed1 = memoryMXBean.getHeapMemoryUsage().getUsed();
  84         sink = new int[1024*1024];
  85         heapUsed2 = memoryMXBean.getHeapMemoryUsage().getUsed();
  86 
  87         long diff = heapUsed2 - heapUsed1 - adj;
  88         long min = 8 + 4*1024*1024;
  89         long max = 16 + 4*1024*1024;
  90         if (!(min <= diff && diff <= max)) {
  91            throw new IllegalStateException("Allocation did not change used space right: " + diff + " should be in [" + min + ", " + max + "]");
  92         }
  93     }
  94 
  95 }