1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   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.
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   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
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  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
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  23 
  24 /**
  25  * @test TestDynShrinkHeap
  26  * @key gc
  27  * @bug 8037924
  28  * @summary Verify that heap shrinking after full gc and dynamically changed free ratio
  29  * @author Andrey Zakharov /andrey.x.zakharov@oracle.com/
  30  * @library /testlibrary
  31  * @run main/othervm -XX:+UseAdaptiveSizePolicyWithSystemGC -XX:+UseParallelGC -XX:MinHeapFreeRatio=1
  32  * -XX:MaxHeapFreeRatio=100 -Xloggc:gc.log TestDynShrinkHeap
  33  */
  34 import java.lang.management.ManagementFactory;
  35 import java.lang.management.MemoryUsage;
  36 import java.util.ArrayList;
  37 import com.oracle.java.testlibrary.TestDynamicVMOption;
  38 import com.oracle.java.testlibrary.MemoryUsagePrinter;
  39 
  40 public class TestDynShrinkHeap {
  41 
  42     public static final String MinFreeRatioFlagName = "MinHeapFreeRatio";
  43     public static final String MaxFreeRatioFlagName = "MaxHeapFreeRatio";
  44 
  45     public static ArrayList<byte[]> list = new ArrayList<byte[]>(0);
  46     public static byte[] temp;
  47     public static final int M = 1024 * 1024; // to make heap more manageable by test code
  48 
  49     private final TestDynamicVMOption minRatioOption;
  50     private final TestDynamicVMOption maxRatioOption;
  51     
  52     public final class Labels {
  53         public static final String beforeAllocation = "before allocation";
  54         public static final String arrayHalfed      = "array halfed";
  55         public static final String underPressure    = "under pressure";
  56         public static final String beforeGc         = "before full GC";
  57         public static final String afterGc          = "after full GC";
  58         
  59     }
  60     
  61 
  62     public TestDynShrinkHeap() {
  63         minRatioOption = new TestDynamicVMOption(MinFreeRatioFlagName);
  64         maxRatioOption = new TestDynamicVMOption(MaxFreeRatioFlagName);
  65     }
  66 
  67     public void test() {
  68         int minHeapFreeValue = minRatioOption.getIntValue();
  69         int maxHeapFreeValue = maxRatioOption.getIntValue();
  70 
  71         // with maxHeapFreeRatio = 100 heap will not shrink at all, so
  72         if (maxHeapFreeValue == 100) {
  73             maxHeapFreeValue = 95;
  74             maxRatioOption.setIntValue(maxHeapFreeValue);
  75         }
  76 
  77         MemoryUsagePrinter.printMemoryUsage(Labels.beforeAllocation);
  78 
  79         for (int i = 0; i < M; i++) {
  80             list.add(new byte[1024]);
  81         }
  82 
  83         MemoryUsagePrinter.printMemoryUsage("allocated " + M + " arrays");
  84 
  85         list.subList(0, M / 2).clear();
  86         gc();
  87         MemoryUsagePrinter.printMemoryUsage(Labels.arrayHalfed);
  88         MemoryUsage muFull = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
  89 
  90         maxRatioOption.setIntValue(minHeapFreeValue + 1);
  91         gc();
  92         MemoryUsagePrinter.printMemoryUsage(Labels.underPressure);
  93         MemoryUsage muPressure = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
  94 
  95         if (!(muPressure.getCommitted() < muFull.getCommitted())) {
  96             StringBuilder strb = new StringBuilder("committed heap size under pressure is not less than committed full heap size, heap hasn't been shrunk?");
  97             strb.append(System.getProperty("line.separator"));
  98             strb.append(MinFreeRatioFlagName + " = " + minHeapFreeValue);
  99             strb.append(System.getProperty("line.separator"));
 100             strb.append(MaxFreeRatioFlagName + " = " + maxHeapFreeValue);
 101             throw new RuntimeException(strb.toString());
 102         }
 103     }
 104 
 105     public static void main(String[] args) {
 106         new TestDynShrinkHeap().test();
 107     }
 108 
 109     public static void gc() {
 110         MemoryUsagePrinter.printMemoryUsage(Labels.beforeGc);
 111         System.gc();
 112         MemoryUsagePrinter.printMemoryUsage(Labels.afterGc);
 113     }
 114 
 115 }