dbuck@8280: /*
dbuck@8280:  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
dbuck@8280:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
dbuck@8280:  *
dbuck@8280:  * This code is free software; you can redistribute it and/or modify it
dbuck@8280:  * under the terms of the GNU General Public License version 2 only, as
dbuck@8280:  * published by the Free Software Foundation.
dbuck@8280:  *
dbuck@8280:  * This code is distributed in the hope that it will be useful, but WITHOUT
dbuck@8280:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
dbuck@8280:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
dbuck@8280:  * version 2 for more details (a copy is included in the LICENSE file that
dbuck@8280:  * accompanied this code).
dbuck@8280:  *
dbuck@8280:  * You should have received a copy of the GNU General Public License version
dbuck@8280:  * 2 along with this work; if not, write to the Free Software Foundation,
dbuck@8280:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
dbuck@8280:  *
dbuck@8280:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
dbuck@8280:  * or visit www.oracle.com if you need additional information or have any
dbuck@8280:  * questions.
dbuck@8280:  */
dbuck@8280: 
dbuck@8280: /*
dbuck@8280:  * @test TestNoEagerReclaimOfHumongousRegions
dbuck@8280:  * @bug 8139424
dbuck@8280:  * @summary Test to check that a live humongous object is not eagerly reclaimed. This is a regression test for
dbuck@8280:  *          8139424 and the test will crash if an eager reclaim occur. The test is not 100% deterministic and
dbuck@8280:  *          might pass even if there are problems in the code, but it will never crash unless there is a problem.
dbuck@8280:  * @requires vm.gc=="G1" | vm.gc=="null"
dbuck@8280:  * @key gc
dbuck@8280:  * @library /testlibrary /testlibrary/whitebox
dbuck@8280:  * @modules java.base/sun.misc
dbuck@8280:  * @build TestNoEagerReclaimOfHumongousRegions
dbuck@8280:  * @run main ClassFileInstaller sun.hotspot.WhiteBox
dbuck@8280:  *                              sun.hotspot.WhiteBox$WhiteBoxPermission
dbuck@8280:  * @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
dbuck@8280:  */
dbuck@8280: 
dbuck@8280: import java.util.LinkedList;
dbuck@8280: 
dbuck@8280: import sun.hotspot.WhiteBox;
dbuck@8280: 
dbuck@8280: public class TestNoEagerReclaimOfHumongousRegions {
dbuck@8280:     // Helper class to keep reference to humongous byte[].
dbuck@8280:     static class LargeRef {
dbuck@8280:         private byte[] _ref;
dbuck@8280: 
dbuck@8280:         LargeRef(byte[] ref) {
dbuck@8280:             _ref = ref;
dbuck@8280:         }
dbuck@8280: 
dbuck@8280:         byte[] ref() { return _ref; }
dbuck@8280:     }
dbuck@8280: 
dbuck@8280:     static LargeRef humongous_reference_holder;
dbuck@8280: 
dbuck@8280:     public static void main(String[] args) throws InterruptedException{
dbuck@8280:         WhiteBox wb = WhiteBox.getWhiteBox();
dbuck@8280:         LinkedList<Object> garbageAndRefList = new LinkedList<Object>();
dbuck@8280:         // Creating a 1M large byte array. Since the test specifies the heap
dbuck@8280:         // region size to be 1m this will be a humongous object. We then
dbuck@8280:         // store a pointer to the array in the static object to keep it live
dbuck@8280:         // during the whole test.
dbuck@8280:         humongous_reference_holder = new LargeRef(new byte[1 * 1024 * 1024]);
dbuck@8280: 
dbuck@8280:         // Create some garbage and a reference to the humongous object each round.
dbuck@8280:         for (int i = 0; i < 32; i++) {
dbuck@8280:             garbageAndRefList.add(new byte[400*1000]);
dbuck@8280:             garbageAndRefList.add(new LargeRef(humongous_reference_holder.ref()));
dbuck@8280: 
dbuck@8280:             // Promote to old, goal is to get rem-set entries for the humongous
dbuck@8280:             // object from different regions. The test specifies MaxTenuringThreshold=0,
dbuck@8280:             // this will make sure we get objects promoted to old at once.
dbuck@8280:             wb.youngGC();
dbuck@8280:         }
dbuck@8280:         // Clear the garbage and reference list.
dbuck@8280:         garbageAndRefList.clear();
dbuck@8280: 
dbuck@8280:         // Run a concurrent mark cycle to mark all references but the static one as dead.
dbuck@8280:         wb.g1StartConcMarkCycle();
dbuck@8280:         while (wb.g1InConcurrentMark()) {
dbuck@8280:             Thread.sleep(100);
dbuck@8280:         }
dbuck@8280: 
dbuck@8280:         // Run a young collection to make sure humongous object still can't be eagerly reclaimed.
dbuck@8280:         wb.youngGC();
dbuck@8280:         // Will crash/assert if humongous object has been reclaimed.
dbuck@8280:         wb.fullGC();
dbuck@8280:     }
dbuck@8280: }