# HG changeset patch # User jwilhelm # Date 1410438073 -7200 # Node ID df66e3a3c4c296f2e9d018280bdd302e8177f474 # Parent a98dd542cd25a58c26f5d8adbe57f26d4145fc82 8041946: CMM Testing: 8u40 an allocated humongous object at the end of the heap should not prevents shrinking the heap Summary: New test added Reviewed-by: jwilhelm, tschatzl Contributed-by: andrey.x.zakharov@oracle.com diff -r a98dd542cd25 -r df66e3a3c4c2 test/gc/g1/TestShrinkDefragmentedHeap.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/gc/g1/TestShrinkDefragmentedHeap.java Thu Sep 11 14:21:13 2014 +0200 @@ -0,0 +1,188 @@ +/* + * Copyright (c) 2014, 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 TestShrinkDefragmentedHeap + * @bug 8038423 + * @summary Verify that heap shrinks after GC in the presence of fragmentation due to humongous objects + * 1. allocate small objects mixed with humongous ones + * "ssssHssssHssssHssssHssssHssssHssssH" + * 2. release all allocated object except the last humongous one + * "..................................H" + * 3. invoke gc and check that memory returned to the system (amount of committed memory got down) + * + * @library /testlibrary + */ +import java.lang.management.ManagementFactory; +import java.lang.management.MemoryUsage; +import java.util.ArrayList; +import java.util.List; +import sun.management.ManagementFactoryHelper; +import static com.oracle.java.testlibrary.Asserts.*; +import com.oracle.java.testlibrary.ProcessTools; +import com.oracle.java.testlibrary.OutputAnalyzer; + +public class TestShrinkDefragmentedHeap { + // Since we store all the small objects, they become old and old regions are also allocated at the bottom of the heap + // together with humongous regions. So if there are a lot of old regions in the lower part of the heap, + // the humongous regions will be allocated in the upper part of the heap anyway. + // To avoid this the Eden needs to be big enough to fit all the small objects. + private static final int INITIAL_HEAP_SIZE = 200 * 1024 * 1024; + private static final int MINIMAL_YOUNG_SIZE = 190 * 1024 * 1024; + private static final int REGION_SIZE = 1 * 1024 * 1024; + + public static void main(String[] args) throws Exception, Throwable { + ProcessBuilder pb = ProcessTools.createJavaProcessBuilder( + "-XX:InitialHeapSize=" + INITIAL_HEAP_SIZE, + "-Xmn" + MINIMAL_YOUNG_SIZE, + "-XX:MinHeapFreeRatio=10", + "-XX:MaxHeapFreeRatio=11", + "-XX:+UseG1GC", + "-XX:G1HeapRegionSize=" + REGION_SIZE, + "-verbose:gc", + GCTest.class.getName() + ); + + OutputAnalyzer output = ProcessTools.executeProcess(pb); + output.shouldHaveExitValue(0); + } + + static class GCTest { + + private static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio"; + private static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio"; + private static final String NEW_SIZE_FLAG_NAME = "NewSize"; + + private static final ArrayList> garbage = new ArrayList<>(); + + private static final int SMALL_OBJS_SIZE = 10 * 1024; // 10kB + private static final int SMALL_OBJS_COUNT = MINIMAL_YOUNG_SIZE / (SMALL_OBJS_SIZE-1); + private static final int ALLOCATE_COUNT = 3; + // try to put all humongous object into gap between min young size and initial heap size + // to avoid implicit GCs + private static final int HUMONG_OBJS_SIZE = (int) Math.max( + (INITIAL_HEAP_SIZE - MINIMAL_YOUNG_SIZE) / ALLOCATE_COUNT / 4, + REGION_SIZE * 1.1 + ); + + private static final long initialHeapSize = getHeapMemoryUsage().getUsed(); + + public static void main(String[] args) throws InterruptedException { + new GCTest().test(); + } + + private void test() throws InterruptedException { + MemoryUsagePrinter.printMemoryUsage("init"); + + allocate(); + System.gc(); + MemoryUsage muFull = getHeapMemoryUsage(); + MemoryUsagePrinter.printMemoryUsage("allocated"); + + free(); + //Thread.sleep(1000); // sleep before measures due lags in JMX + MemoryUsage muFree = getHeapMemoryUsage(); + MemoryUsagePrinter.printMemoryUsage("free"); + + assertLessThan(muFree.getCommitted(), muFull.getCommitted(), prepareMessageCommittedIsNotLess() ); + } + + private void allocate() { + System.out.format("Will allocate objects of small size = %s and humongous size = %s", + MemoryUsagePrinter.humanReadableByteCount(SMALL_OBJS_SIZE, false), + MemoryUsagePrinter.humanReadableByteCount(HUMONG_OBJS_SIZE, false) + ); + + for (int i = 0; i < ALLOCATE_COUNT; i++) { + ArrayList stuff = new ArrayList<>(); + allocateList(stuff, SMALL_OBJS_COUNT / ALLOCATE_COUNT, SMALL_OBJS_SIZE); + garbage.add(stuff); + + ArrayList humongousStuff = new ArrayList<>(); + allocateList(humongousStuff, 4, HUMONG_OBJS_SIZE); + garbage.add(humongousStuff); + } + } + + private void free() { + // do not free last one list + garbage.subList(0, garbage.size() - 1).clear(); + + // do not free last one element from last list + ArrayList stuff = garbage.get(garbage.size() - 1); + if (stuff.size() > 1) { + stuff.subList(0, stuff.size() - 1).clear(); + } + System.gc(); + } + + private String prepareMessageCommittedIsNotLess() { + return String.format( + "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n" + + "%s = %s%n%s = %s", + MIN_FREE_RATIO_FLAG_NAME, + ManagementFactoryHelper.getDiagnosticMXBean().getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(), + MAX_FREE_RATIO_FLAG_NAME, + ManagementFactoryHelper.getDiagnosticMXBean().getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue() + ); + } + + private static void allocateList(List garbage, int count, int size) { + for (int i = 0; i < count; i++) { + garbage.add(new byte[size]); + } + } + } + + static MemoryUsage getHeapMemoryUsage() { + return ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); + } + + /** + * Prints memory usage to standard output + */ + static class MemoryUsagePrinter { + + public static String humanReadableByteCount(long bytes, boolean si) { + int unit = si ? 1000 : 1024; + if (bytes < unit) { + return bytes + " B"; + } + int exp = (int) (Math.log(bytes) / Math.log(unit)); + String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp - 1) + (si ? "" : "i"); + return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre); + } + + public static void printMemoryUsage(String label) { + MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); + float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted(); + System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n", + label, + humanReadableByteCount(memusage.getInit(), false), + humanReadableByteCount(memusage.getUsed(), false), + humanReadableByteCount(memusage.getCommitted(), false), + freeratio * 100 + ); + } + } +}