| /* |
| * Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test TestEagerReclaimHumongousRegionsWithRefs |
| * @bug 8048179 |
| * @summary Test to make sure that eager reclaim of humongous objects that have previously |
| * been referenced by other old gen regions work. We simply try to fill |
| * up the heap with humongous objects and create a remembered set entry from an object by |
| * referencing that we know is in the old gen. After changing this reference, the object |
| * should still be eagerly reclaimable to avoid Full GC. |
| * @key gc |
| * @requires vm.gc.G1 |
| * @library /test/lib |
| * @modules java.base/jdk.internal.misc |
| * java.management |
| */ |
| |
| import java.util.regex.Pattern; |
| import java.util.regex.Matcher; |
| import java.util.LinkedList; |
| |
| import jdk.test.lib.process.OutputAnalyzer; |
| import jdk.test.lib.process.ProcessTools; |
| import static jdk.test.lib.Asserts.*; |
| |
| class RefHolder { |
| Object ref; |
| } |
| |
| class ReclaimRegionFast { |
| |
| public static final int M = 1024*1024; |
| |
| public static LinkedList<Object> garbageList = new LinkedList<Object>(); |
| |
| public static void genGarbage() { |
| for (int i = 0; i < 32*1024; i++) { |
| garbageList.add(new int[100]); |
| } |
| garbageList.clear(); |
| } |
| |
| |
| // A large object referenced by a static. |
| static int[] filler = new int[10 * M]; |
| |
| // Old gen object referencing the large object, generating remembered |
| // set entries. |
| static RefHolder fromOld = new RefHolder(); |
| |
| public static void main(String[] args) { |
| |
| int[] large = new int[M]; |
| |
| Object ref_from_stack = large; |
| |
| for (int i = 0; i < 100; i++) { |
| // A large object that will be reclaimed eagerly. |
| large = new int[6*M]; |
| fromOld.ref = large; |
| genGarbage(); |
| } |
| |
| // Keep the reference to the first object alive. |
| System.out.println(ref_from_stack); |
| } |
| } |
| |
| public class TestEagerReclaimHumongousRegionsWithRefs { |
| |
| public static void main(String[] args) throws Exception { |
| ProcessBuilder pb = ProcessTools.createJavaProcessBuilder( |
| "-XX:+UseG1GC", |
| "-Xms128M", |
| "-Xmx128M", |
| "-Xmn16M", |
| "-Xlog:gc", |
| ReclaimRegionFast.class.getName()); |
| |
| Pattern p = Pattern.compile("Full GC"); |
| |
| OutputAnalyzer output = new OutputAnalyzer(pb.start()); |
| |
| int found = 0; |
| Matcher m = p.matcher(output.getStdout()); |
| while (m.find()) { |
| found++; |
| } |
| System.out.println("Issued " + found + " Full GCs"); |
| |
| assertLessThan(found, 10, "Found that " + found + " Full GCs were issued. This is larger than the bound. Eager reclaim of objects once referenced from old gen seems to not work at all"); |
| output.shouldHaveExitValue(0); |
| } |
| } |
| |