8037925: CMM Testing: an allocated humongous object at the end of the heap should not prevents shrinking the heap
Summary: New test added.
Reviewed-by: ehelin, tschatzl, jwilhelm
Contributed-by: andrey.x.zakharov@oracle.com
--- a/hotspot/test/TEST.groups Mon Apr 14 10:08:10 2014 +0200
+++ b/hotspot/test/TEST.groups Tue Apr 15 18:09:53 2014 +0200
@@ -127,6 +127,7 @@
gc/6581734/Test6581734.java \
gc/7072527/TestFullGCCount.java \
gc/g1/TestHumongousAllocInitialMark.java \
+ gc/g1/TestHumongousShrinkHeap.java \
gc/arguments/TestG1HeapRegionSize.java \
gc/metaspace/TestMetaspaceMemoryPool.java \
gc/arguments/TestDynMinHeapFreeRatio.java \
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/gc/g1/TestHumongousShrinkHeap.java Tue Apr 15 18:09:53 2014 +0200
@@ -0,0 +1,131 @@
+/*
+ * 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 TestHumongousShrinkHeap
+ * @bug 8036025
+ * @summary Verify that heap shrinks after GC in the presence of fragmentation due to humongous objects
+ * @library /testlibrary
+ * @run main/othervm -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=50 -XX:+UseG1GC -XX:G1HeapRegionSize=1M -verbose:gc TestHumongousShrinkHeap
+ */
+
+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.*;
+
+public class TestHumongousShrinkHeap {
+
+ public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio";
+ public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio";
+
+ private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>();
+ private static final int PAGE_SIZE = 1024 * 1024; // 1M
+ private static final int PAGES_NUM = 5;
+
+
+ public static void main(String[] args) {
+ new TestHumongousShrinkHeap().test();
+ }
+
+ private final void test() {
+ System.gc();
+ MemoryUsagePrinter.printMemoryUsage("init");
+
+ eat();
+ MemoryUsagePrinter.printMemoryUsage("eaten");
+ MemoryUsage muFull = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
+
+ free();
+ MemoryUsagePrinter.printMemoryUsage("free");
+ MemoryUsage muFree = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
+
+ assertLessThan(muFree.getCommitted(), muFull.getCommitted(), 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 void eat() {
+ int HumongousObjectSize = Math.round(.9f * PAGE_SIZE);
+ System.out.println("Will allocate objects of size=" +
+ MemoryUsagePrinter.humanReadableByteCount(HumongousObjectSize, true));
+
+ for (int i = 0; i < PAGES_NUM; i++) {
+ ArrayList<byte[]> stuff = new ArrayList<>();
+ eatList(stuff, 100, HumongousObjectSize);
+ MemoryUsagePrinter.printMemoryUsage("eat #" + i);
+ garbage.add(stuff);
+ }
+ }
+
+ 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);
+ stuff.subList(0, stuff.size() - 1).clear();
+ System.gc();
+ }
+
+ private static void eatList(List garbage, int count, int size) {
+ for (int i = 0; i < count; i++) {
+ garbage.add(new byte[size]);
+ }
+ }
+}
+
+/**
+ * Prints memory usage to standard output
+ */
+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(), true),
+ humanReadableByteCount(memusage.getUsed(), true),
+ humanReadableByteCount(memusage.getCommitted(), true),
+ freeratio * 100
+ );
+ }
+}