1 /*
   2  * Copyright (c) 2020, 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 package gc.z;
  25 
  26 /*
  27  * @test TestNoUncommit
  28  * @requires vm.gc.Z & !vm.graal.enabled
  29  * @summary Test ZGC uncommit unused memory disabled
  30  * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+heap=debug,gc+stats=off -Xms512M -Xmx512M -XX:ZUncommitDelay=1 gc.z.TestNoUncommit
  31  * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+heap=debug,gc+stats=off -Xms128M -Xmx512M -XX:ZUncommitDelay=1 -XX:-ZUncommit gc.z.TestNoUncommit
  32  */
  33 
  34 public class TestNoUncommit {
  35     private static final int allocSize = 200 * 1024 * 1024; // 200M
  36     private static volatile Object keepAlive = null;
  37 
  38     private static long capacity() {
  39         return Runtime.getRuntime().totalMemory();
  40     }
  41 
  42     public static void main(String[] args) throws Exception {
  43         System.out.println("Allocating");
  44         keepAlive = new byte[allocSize];
  45         final var afterAlloc = capacity();
  46 
  47         System.out.println("Reclaiming");
  48         keepAlive = null;
  49         System.gc();
  50 
  51         // Wait longer than the uncommit delay (which is 1 second)
  52         Thread.sleep(5 * 1000);
  53 
  54         final var afterDelay = capacity();
  55 
  56         // Verify
  57         if (afterAlloc > afterDelay) {
  58             throw new Exception("Should not uncommit");
  59         }
  60 
  61         System.out.println("Success");
  62     }
  63 }