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 TestEagerReclaimHumongousRegions 26 * @bug 8027959 27 * @summary Test to make sure that eager reclaim of humongous objects work. We simply try to fill 28 * up the heap with humongous objects that should be eagerly reclaimable to avoid Full GC. 29 * @key gc 30 * @library /testlibrary 31 */ 32 33 import java.util.regex.Pattern; 34 import java.util.regex.Matcher; 35 import java.util.LinkedList; 36 37 import com.oracle.java.testlibrary.OutputAnalyzer; 38 import com.oracle.java.testlibrary.ProcessTools; 39 import com.oracle.java.testlibrary.Asserts; 40 41 class ReclaimRegionFast { 42 public static final int M = 1024*1024; 43 44 public static LinkedList<Object> garbageList = new LinkedList<Object>(); 45 46 public static void genGarbage() { 47 for (int i = 0; i < 32*1024; i++) { 48 garbageList.add(new int[100]); 49 } 50 garbageList.clear(); 51 } 52 53 // A large object referenced by a static. 54 static int[] filler = new int[10 * M]; 55 56 public static void main(String[] args) { 57 58 int[] large = new int[M]; 59 60 Object ref_from_stack = large; 61 62 for (int i = 0; i < 100; i++) { 63 // A large object that will be reclaimed eagerly. 64 large = new int[6*M]; 65 genGarbage(); 66 // Make sure that the compiler cannot completely remove 67 // the allocation of the large object until here. 68 System.out.println(large); 69 } 70 71 // Keep the reference to the first object alive. 72 System.out.println(ref_from_stack); 73 } 74 } 75 76 public class TestEagerReclaimHumongousRegions { 77 public static void main(String[] args) throws Exception { 78 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder( 79 "-XX:+UseG1GC", 80 "-Xms128M", 81 "-Xmx128M", 82 "-Xmn16M", 83 "-XX:+PrintGC", 84 ReclaimRegionFast.class.getName()); 85 86 Pattern p = Pattern.compile("Full GC"); 87 88 OutputAnalyzer output = new OutputAnalyzer(pb.start()); 89 90 int found = 0; 91 Matcher m = p.matcher(output.getStdout()); 92 while (m.find()) { found++; } 93 System.out.println("Issued " + found + " Full GCs"); 94 Asserts.assertLT(found, 10, "Found that " + found + " Full GCs were issued. This is larger than the bound. Eager reclaim seems to not work at all"); 95 96 output.shouldHaveExitValue(0); 97 } 98 }