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 TestDynShrinkHeap
  26  * @bug 8016479
  27  * @summary Verify that heap shrinking after full gc and dynamically changed free ratio
  28  * @library /testlibrary
  29  * @run main/othervm -XX:+UseAdaptiveSizePolicyWithSystemGC -XX:+UseParallelGC -XX:MinHeapFreeRatio=0 -XX:MaxHeapFreeRatio=100 -Xloggc:gc.log TestDynShrinkHeap
  30  */
  31 
  32 import com.oracle.java.testlibrary.TestDynamicVMOption;
  33 import com.oracle.java.testlibrary.gc.MemoryUsagePrinter;
  34 import com.oracle.java.testlibrary.gc.TestShrinkHeap;
  35 import java.util.ArrayList;
  36 
  37 public class TestDynShrinkHeap extends TestShrinkHeap {
  38 
  39     public static ArrayList<byte[]> list = new ArrayList<>(0);
  40     public static final int M = 1024 * 1024; // to make heap more manageable by test code
  41     
  42     private final TestDynamicVMOption maxRatioOption;   
  43     private final TestDynamicVMOption minRatioOption;   
  44 
  45     public TestDynShrinkHeap() {
  46         super();
  47         minRatioOption = new TestDynamicVMOption(MIN_FREE_RATIO_FLAG_NAME);
  48         maxRatioOption = new TestDynamicVMOption(MAX_FREE_RATIO_FLAG_NAME);
  49 
  50         // with maxHeapFreeRatio = 100 heap will not shrink at all, so
  51         if (maxRatioOption.getIntValue() == 100) {
  52             maxRatioOption.setIntValue(95);
  53         }
  54     }
  55     
  56     protected void eat() {
  57         for (int i = 0; i < M; i++) {
  58             list.add(new byte[1024]);
  59         }
  60         MemoryUsagePrinter.printMemoryUsage("allocated " + M + " arrays");
  61         
  62         list.subList(0, M / 2).clear();
  63         System.gc();
  64         MemoryUsagePrinter.printMemoryUsage("array halfed");
  65     }
  66 
  67     protected void free() {  
  68         maxRatioOption.setIntValue(minRatioOption.getIntValue() + 1);
  69         System.gc();
  70         MemoryUsagePrinter.printMemoryUsage("under pressure");
  71     }
  72 
  73     public static void main(String[] args) {
  74         new TestDynShrinkHeap().test();
  75     }
  76 }