afb458ef0e
Push the remembered sets of large objects with few referenced into the dirty card queue at the beginning of the evacuation so that they may end up with zero remembered set entries at the end of the collection, and are potentially reclaimed. Also improve timing measurements of the early reclaim mechanism, and shorten flag names. Reviewed-by: brutisso, jmasa, dfazunen
114 lines
3.7 KiB
Java
114 lines
3.7 KiB
Java
/*
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* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test TestEagerReclaimHumongousRegionsWithRefs
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* @bug 8048179
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* @summary Test to make sure that eager reclaim of humongous objects that have previously
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* been referenced by other old gen regions work. We simply try to fill
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* up the heap with humongous objects and create a remembered set entry from an object by
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* referencing that we know is in the old gen. After changing this reference, the object
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* should still be eagerly reclaimable to avoid Full GC.
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* @key gc
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* @library /testlibrary
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*/
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import java.util.regex.Pattern;
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import java.util.regex.Matcher;
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import java.util.LinkedList;
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import com.oracle.java.testlibrary.OutputAnalyzer;
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import com.oracle.java.testlibrary.ProcessTools;
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import static com.oracle.java.testlibrary.Asserts.*;
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class RefHolder {
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Object ref;
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}
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class ReclaimRegionFast {
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public static final int M = 1024*1024;
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public static LinkedList<Object> garbageList = new LinkedList<Object>();
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public static void genGarbage() {
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for (int i = 0; i < 32*1024; i++) {
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garbageList.add(new int[100]);
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}
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garbageList.clear();
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}
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// A large object referenced by a static.
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static int[] filler = new int[10 * M];
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// Old gen object referencing the large object, generating remembered
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// set entries.
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static RefHolder fromOld = new RefHolder();
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public static void main(String[] args) {
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int[] large = new int[M];
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Object ref_from_stack = large;
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for (int i = 0; i < 100; i++) {
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// A large object that will be reclaimed eagerly.
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large = new int[6*M];
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fromOld.ref = large;
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genGarbage();
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}
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// Keep the reference to the first object alive.
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System.out.println(ref_from_stack);
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}
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}
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public class TestEagerReclaimHumongousRegionsWithRefs {
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public static void main(String[] args) throws Exception {
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ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
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"-XX:+UseG1GC",
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"-Xms128M",
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"-Xmx128M",
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"-Xmn16M",
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"-XX:+PrintGC",
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ReclaimRegionFast.class.getName());
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Pattern p = Pattern.compile("Full GC");
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OutputAnalyzer output = new OutputAnalyzer(pb.start());
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int found = 0;
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Matcher m = p.matcher(output.getStdout());
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while (m.find()) {
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found++;
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}
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System.out.println("Issued " + found + " Full GCs");
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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");
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output.shouldHaveExitValue(0);
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}
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}
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