1 /* 2 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 package gc.z; 25 26 /* 27 * @test TestPageCacheFlush 28 * @requires vm.gc.Z 29 * @summary Test ZGC page cache flushing 30 * @library /test/lib 31 * @run driver gc.z.TestPageCacheFlush 32 */ 33 34 import java.util.LinkedList; 35 import jdk.test.lib.process.ProcessTools; 36 37 public class TestPageCacheFlush { 38 static class Test { 39 private static final int K = 1024; 40 private static final int M = K * K; 41 private static volatile LinkedList<byte[]> keepAlive; 42 43 public static void fillPageCache(int size) { 44 System.out.println("Begin allocate (" + size + ")"); 45 46 keepAlive = new LinkedList<>(); 47 48 try { 49 for (;;) { 50 keepAlive.add(new byte[size]); 51 } 52 } catch (OutOfMemoryError e) { 53 keepAlive = null; 54 System.gc(); 55 } 56 57 System.out.println("End allocate (" + size + ")"); 58 } 59 60 public static void main(String[] args) throws Exception { 61 // Allocate small objects to fill the page cache with small pages 62 fillPageCache(10 * K); 63 64 // Allocate large objects to provoke page cache flushing to rebuild 65 // cached small pages into large pages 66 fillPageCache(10 * M); 67 } 68 } 69 70 public static void main(String[] args) throws Exception { 71 ProcessTools.executeProcess(ProcessTools.createJavaProcessBuilder( 72 "-XX:+UseZGC", 73 "-Xms128M", 74 "-Xmx128M", 75 "-Xlog:gc,gc+init,gc+heap=debug", 76 Test.class.getName())) 77 .outputTo(System.out) 78 .errorTo(System.out) 79 .shouldContain("Page Cache Flushed:") 80 .shouldHaveExitValue(0); 81 } 82 }