--- /dev/null 2017-10-30 10:02:53.732784560 +0100 +++ new/test/hotspot/jtreg/gc/stress/TestReclaimStringsLeaksMemory.java 2017-11-27 16:16:01.981505776 +0100 @@ -0,0 +1,103 @@ +/* + * Copyright (c) 2017, 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 TestReclaimStringsLeaksMemory + * @bug 8180048 + * @summary Ensure that during a Full GC interned string memory is reclaimed completely. + * @requires vm.gc=="null" + * @requires !vm.debug + * @key gc + * @library /test/lib + * @modules java.base/jdk.internal.misc + * @run main/othervm TestReclaimStringsLeaksMemory + * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseSerialGC + * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseParallelGC + * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseParallelGC -XX:-UseParallelOldGC + * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseConcMarkSweepGC + * @run main/othervm TestReclaimStringsLeaksMemory -XX:+UseG1GC + */ + +import java.util.Arrays; +import java.util.ArrayList; +import java.util.regex.Pattern; +import java.util.regex.Matcher; + +import jdk.test.lib.Asserts; +import jdk.test.lib.process.OutputAnalyzer; +import jdk.test.lib.process.ProcessTools; + +public class TestReclaimStringsLeaksMemory { + + // The amount of memory in kB reserved in the "Symbol" category that indicates a memory leak for + // this test. + public static final int ReservedThreshold = 70000; + + public static void main(String[] args) throws Exception { + ArrayList baseargs = new ArrayList(Arrays.asList( "-Xms256M", + "-Xmx256M", + "-Xlog:gc*", + "-XX:NativeMemoryTracking=summary", + "-XX:+UnlockDiagnosticVMOptions", + "-XX:+PrintNMTStatistics" )); + baseargs.addAll(Arrays.asList(args)); + baseargs.add(GCTest.class.getName()); + ProcessBuilder pb_default = + ProcessTools.createJavaProcessBuilder(baseargs.toArray(new String[] {})); + verifySymbolMemoryUsageNotTooHigh(new OutputAnalyzer(pb_default.start())); + } + + private static void verifySymbolMemoryUsageNotTooHigh(OutputAnalyzer output) throws Exception { + String stdout = output.getStdout(); + System.out.println(stdout); + + Pattern p = Pattern.compile("Symbol \\(reserved=(\\d*)"); + Matcher m = p.matcher(stdout); + + if (!m.find()) { + throw new RuntimeException("Could not find Symbol memory usage in NMT output"); + } + + int reserved = Integer.parseInt(m.group(1)); + Asserts.assertLT(reserved, ReservedThreshold, "Reserved memory size is " + reserved + "KB which is higher than " + ReservedThreshold + "KB indicating a memory leak"); + + output.shouldHaveExitValue(0); + } + + static class GCTest { + public static final String BaseName = "SomeRandomBaseString"; + public static volatile String lastString; + + public static void main(String [] args) { + for (int iterations = 0; iterations < 20;) { + for (int i = 0; i < 1000000; i++) { + lastString = (BaseName + i).intern(); + } + if (++iterations % 5 == 0) { + System.gc(); + } + } + } + } +} +