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 8036025 27 * @summary Verify that heap shrinking after GC of hard defragmented by humongous object heap 28 * @library /testlibrary 29 * @run main/othervm -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=50 -XX:+UseG1GC -XX:G1HeapRegionSize=1M -Xloggc:gc_10_50.log TestHumongousShrinkHeap 30 */ 31 32 import com.oracle.java.testlibrary.gc.MemoryUsagePrinter; 33 import com.oracle.java.testlibrary.gc.TestShrinkHeap; 34 import java.util.ArrayList; 35 import java.util.List; 36 37 public class TestHumongousShrinkHeap extends TestShrinkHeap { 38 39 private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>(); 40 private static final int PAGE_SIZE = 1024 * 1024; // 1M 41 private static final int PAGES_NUM = 5; 42 43 public TestHumongousShrinkHeap() { 44 super(); 45 } 46 47 protected void eat() { 48 int HumongousObjectSize = Math.round(.9f * PAGE_SIZE); 49 System.out.println("Will allocate objects of size=" + 50 MemoryUsagePrinter.humanReadableByteCount(HumongousObjectSize, true)); 51 52 for (int i = 0; i < PAGES_NUM; i++) { 53 ArrayList<byte[]> stuff = new ArrayList<>(); 54 eatList(stuff, 100, HumongousObjectSize); 55 MemoryUsagePrinter.printMemoryUsage("eat #" + i); 56 garbage.add(stuff); 57 } 58 } 59 60 protected void free() { 61 // do not free last one list 62 garbage.subList(0, garbage.size() - 1).clear(); 63 64 // do not free last one element from last list 65 ArrayList stuff = garbage.get(garbage.size() - 1); 66 stuff.subList(0, stuff.size() - 1).clear(); 67 System.gc(); 68 } 69 70 public static void main(String[] args) { 71 new TestHumongousShrinkHeap().test(); 72 } 73 74 private static void eatList(List garbage, int count, int size) { 75 for (int i = 0; i < count; i++) { 76 garbage.add(new byte[size]); 77 } 78 } 79 }