russell@unturf.com
0a580b313d
Authors: russell@unturf.com · brackishbert@gmail.com · foxhop.net · TimeHexOn.com Patches, unit tests, benchmarks, whitepaper, and outreach briefs. Public domain — no copyright claimed. Use freely.
97 lines
3.6 KiB
Java
97 lines
3.6 KiB
Java
/*
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* Copyright (c) 2025, 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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package gc.z;
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/*
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* @test TestMappedCacheHarvest
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* @requires vm.gc.Z
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* @summary Test ZGC mapped cache harvesting
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* @library /test/lib
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* @run driver gc.z.TestMappedCacheHarvest
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*/
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import java.util.ArrayList;
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import java.lang.instrument.Instrumentation;
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import jdk.test.lib.process.ProcessTools;
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public class TestMappedCacheHarvest {
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static class Test {
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private static int M = 1024 * 1024;
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private static int LARGE = 33 * M;
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private static int MEDIUM = 3 * M;
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public volatile static byte[] tmp;
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private static long freeMem() {
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long currentlyCommitted = Runtime.getRuntime().totalMemory();
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long currentlyFree = Runtime.getRuntime().freeMemory();
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long max = Runtime.getRuntime().maxMemory();
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return max - (currentlyCommitted - currentlyFree);
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}
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public static void main(String[] args) throws Exception {
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int iter = 0;
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ArrayList<byte[]> keep = new ArrayList<>();
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try {
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// Interleave ever growing different sized allocation while
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// keeping the smaller allocations alive until the heap is full
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// and having the larger allocations be transient.
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while (freeMem() > LARGE) {
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tmp = new byte[LARGE];
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keep.add(new byte[MEDIUM]);
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System.gc();
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LARGE += 2*M;
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if (freeMem() < LARGE) {
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// Release the keep to see if we can continue
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keep = new ArrayList<>();
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System.gc();
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MEDIUM += 2*M;
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}
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}
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System.out.println("Last large size: " + LARGE / M + "M (" + iter + ") Free mem: " +
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Runtime.getRuntime().freeMemory() / M + "M" );
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} catch (OutOfMemoryError oome) {
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keep = null;
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System.out.println("Premature OOME: large size: " + LARGE / M + "M (" + iter + ") Free mem: " +
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Runtime.getRuntime().freeMemory() / M + "M" );
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}
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}
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}
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public static void main(String[] args) throws Exception {
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ProcessTools.executeTestJava(
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"-XX:+UseZGC",
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"-Xms128M",
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"-Xmx128M",
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"-Xlog:gc,gc+init,gc+heap=debug",
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Test.class.getName())
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.outputTo(System.out)
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.errorTo(System.out)
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.shouldContain("Mapped Cache Harvested:")
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.shouldNotContain("Out of address space")
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.shouldHaveExitValue(0);
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}
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}
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