| /* |
| * Copyright (c) 2015, 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 TestNoEagerReclaimOfHumongousRegions |
| * @bug 8139424 |
| * @summary Test to check that a live humongous object is not eagerly reclaimed. This is a regression test for |
| * 8139424 and the test will crash if an eager reclaim occur. The test is not 100% deterministic and |
| * might pass even if there are problems in the code, but it will never crash unless there is a problem. |
| * @requires vm.gc=="G1" | vm.gc=="null" |
| * @key gc |
| * @library /testlibrary /testlibrary/whitebox |
| * @modules java.base/sun.misc |
| * @build TestNoEagerReclaimOfHumongousRegions |
| * @run main ClassFileInstaller sun.hotspot.WhiteBox |
| * sun.hotspot.WhiteBox$WhiteBoxPermission |
| * @run main/othervm -Xbootclasspath/a:. -XX:+PrintGC -XX:+UseG1GC -XX:MaxTenuringThreshold=0 -XX:G1RSetSparseRegionEntries=32 -XX:G1HeapRegionSize=1m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:+UnlockExperimentalVMOptions -XX:+G1TraceEagerReclaimHumongousObjects TestNoEagerReclaimOfHumongousRegions |
| */ |
| |
| import java.util.LinkedList; |
| |
| import sun.hotspot.WhiteBox; |
| |
| public class TestNoEagerReclaimOfHumongousRegions { |
| // Helper class to keep reference to humongous byte[]. |
| static class LargeRef { |
| private byte[] _ref; |
| |
| LargeRef(byte[] ref) { |
| _ref = ref; |
| } |
| |
| byte[] ref() { return _ref; } |
| } |
| |
| static LargeRef humongous_reference_holder; |
| |
| public static void main(String[] args) throws InterruptedException{ |
| WhiteBox wb = WhiteBox.getWhiteBox(); |
| LinkedList<Object> garbageAndRefList = new LinkedList<Object>(); |
| // Creating a 1M large byte array. Since the test specifies the heap |
| // region size to be 1m this will be a humongous object. We then |
| // store a pointer to the array in the static object to keep it live |
| // during the whole test. |
| humongous_reference_holder = new LargeRef(new byte[1 * 1024 * 1024]); |
| |
| // Create some garbage and a reference to the humongous object each round. |
| for (int i = 0; i < 32; i++) { |
| garbageAndRefList.add(new byte[400*1000]); |
| garbageAndRefList.add(new LargeRef(humongous_reference_holder.ref())); |
| |
| // Promote to old, goal is to get rem-set entries for the humongous |
| // object from different regions. The test specifies MaxTenuringThreshold=0, |
| // this will make sure we get objects promoted to old at once. |
| wb.youngGC(); |
| } |
| // Clear the garbage and reference list. |
| garbageAndRefList.clear(); |
| |
| // Run a concurrent mark cycle to mark all references but the static one as dead. |
| wb.g1StartConcMarkCycle(); |
| while (wb.g1InConcurrentMark()) { |
| Thread.sleep(100); |
| } |
| |
| // Run a young collection to make sure humongous object still can't be eagerly reclaimed. |
| wb.youngGC(); |
| // Will crash/assert if humongous object has been reclaimed. |
| wb.fullGC(); |
| } |
| } |