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 import sun.hotspot.WhiteBox;
  25 
  26 class AllocateBeyondMetaspaceSize {
  27   public static Object dummy;
  28 
  29   public static void main(String [] args) {
  30     if (args.length != 2) {
  31       throw new IllegalArgumentException("Usage: <MetaspaceSize> <YoungGenSize>");
  32     }
  33 
  34     long metaspaceSize = Long.parseLong(args[0]);
  35     long youngGenSize = Long.parseLong(args[1]);
  36 
  37     run(metaspaceSize, youngGenSize);
  38   }
  39 
  40   private static void run(long metaspaceSize, long youngGenSize) {
  41     WhiteBox wb = WhiteBox.getWhiteBox();
  42 
  43     long allocationBeyondMetaspaceSize  = metaspaceSize * 2;
  44     long metaspace = wb.allocateMetaspace(null, allocationBeyondMetaspaceSize);
  45 
  46     triggerYoungGC(youngGenSize);
  47 
  48     wb.freeMetaspace(null, metaspace, metaspace);
  49   }
  50 
  51   private static void triggerYoungGC(long youngGenSize) {
  52     long approxAllocSize = 32 * 1024;
  53     long numAllocations  = 2 * youngGenSize / approxAllocSize;
  54 
  55     for (long i = 0; i < numAllocations; i++) {
  56       dummy = new byte[(int)approxAllocSize];
  57     }
  58   }
  59 }