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 TestHumongousShrinkHeap
  26  * @bug 8037925
  27  * @summary Verify that heap shrinking after GC of hard defragmented by humongous object heap
  28  * @author Andrey Zakharov /andrey.x.zakharov@oracle.com/
  29  * @author Dmitry Fazunenko /dmitry.fazunenko@oracle.com/
  30  * @library /testlibrary
  31  * @run main/othervm -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=50 -XX:+UseG1GC -XX:G1HeapRegionSize=1M -Xloggc:gc_10_50.log TestHumongousShrinkHeap
  32  */
  33 import com.oracle.java.testlibrary.gc.MemoryUsagePrinter;
  34 import com.oracle.java.testlibrary.gc.TestShrinkHeap;
  35 import java.util.ArrayList;
  36 import java.util.List;
  37 
  38 public class TestHumongousShrinkHeap extends TestShrinkHeap {
  39 
  40     private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>();
  41     private static final int PAGE_SIZE = 1024 * 1024; // 1M 
  42     private static final int PAGES_NUM = 5;
  43 
  44     public TestHumongousShrinkHeap() {
  45         super();
  46     }
  47 
  48     public void eat() {
  49         int HumongousObjectSize = Math.round(.9f * PAGE_SIZE);
  50         System.out.println("Will allocate objects of size=" + 
  51                 MemoryUsagePrinter.humanReadableByteCount(HumongousObjectSize, true));
  52         
  53         for (int i = 0; i < PAGES_NUM; i++) {
  54             ArrayList<byte[]> stuff = new ArrayList<>();
  55             eatList(stuff, 100, HumongousObjectSize);
  56             MemoryUsagePrinter.printMemoryUsage("eat #" + i);
  57             garbage.add(stuff);
  58         }
  59     }
  60 
  61     public void free() {
  62         //do not free last one list
  63         garbage.subList(0, garbage.size() - 1).clear();
  64 
  65         // do not free last one element from last list
  66         ArrayList stuff = garbage.get(garbage.size() - 1);
  67         stuff.subList(0, stuff.size() - 1).clear();
  68         System.gc();
  69     }
  70 
  71     public static void main(String[] args) {
  72         new TestHumongousShrinkHeap().test();
  73     }
  74 
  75     private static void eatList(List garbage, int count, int size) {
  76         for (int i = 0; i < count; i++) {
  77             garbage.add(new byte[size]);
  78         }
  79     }
  80 }