| /* |
| * Copyright (c) 2020, 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. |
| */ |
| |
| package gc.stress; |
| |
| /* |
| * @test TestStressUncommit |
| * @key stress |
| * @summary Stress uncommitting by allocating and releasing memory |
| * @requires vm.gc.G1 |
| * @library /test/lib |
| * @modules java.base/jdk.internal.misc |
| * @run driver/timeout=1300 gc.stress.TestStressG1Uncommit |
| */ |
| |
| import java.lang.management.ManagementFactory; |
| import java.lang.management.MemoryMXBean; |
| import java.time.Duration; |
| import java.time.Instant; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.LinkedList; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.TimeUnit; |
| import com.sun.management.ThreadMXBean; |
| |
| import jdk.test.lib.Asserts; |
| import jdk.test.lib.process.ProcessTools; |
| import jdk.test.lib.process.OutputAnalyzer; |
| |
| public class TestStressG1Uncommit { |
| public static void main(String[] args) throws Exception { |
| ArrayList<String> options = new ArrayList<>(); |
| Collections.addAll(options, |
| "-Xlog:gc,gc+heap+region=debug", |
| "-XX:+UseG1GC", |
| StressUncommit.class.getName() |
| ); |
| ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(options); |
| OutputAnalyzer output = new OutputAnalyzer(pb.start()); |
| output.shouldHaveExitValue(0); |
| output.shouldMatch("Uncommit regions"); |
| output.outputTo(System.out); |
| } |
| } |
| |
| class StressUncommit { |
| private static final long M = 1024 * 1024; |
| private static final long G = 1024 * M; |
| private static final Instant StartTime = Instant.now(); |
| |
| private static final ThreadMXBean threadBean = (ThreadMXBean) ManagementFactory.getThreadMXBean(); |
| private static final MemoryMXBean memoryBean = ManagementFactory.getMemoryMXBean(); |
| private static ConcurrentLinkedQueue<Object> globalKeepAlive; |
| |
| public static void main(String args[]) throws InterruptedException { |
| // Leave 20% head room to try to avoid Full GCs. |
| long allocationSize = (long) (Runtime.getRuntime().maxMemory() * 0.8); |
| |
| // Figure out suitable number of workers (~1 per gig). |
| int gigsOfAllocation = (int) Math.ceil((double) allocationSize / G); |
| int numWorkers = Math.min(gigsOfAllocation, Runtime.getRuntime().availableProcessors()); |
| long workerAllocation = allocationSize / numWorkers; |
| |
| log("Using " + numWorkers + " workers, each allocating: ~" + (workerAllocation / M) + "M"); |
| ExecutorService workers = Executors.newFixedThreadPool(numWorkers); |
| try { |
| int iteration = 1; |
| // Run for 60 seconds. |
| while (uptime() < 60) { |
| log("Interation: " + iteration++); |
| globalKeepAlive = new ConcurrentLinkedQueue<>(); |
| // Submit work to executor. |
| CountDownLatch workersRunning = new CountDownLatch(numWorkers); |
| for (int j = 0; j < numWorkers; j++) { |
| // Submit worker task. |
| workers.submit(() -> { |
| allocateToLimit(workerAllocation); |
| workersRunning.countDown(); |
| }); |
| } |
| |
| // Wait for tasks to complete. |
| workersRunning.await(); |
| |
| // Clear the reference holding all task allocations alive. |
| globalKeepAlive = null; |
| |
| // Do a GC that should shrink the heap. |
| long committedBefore = memoryBean.getHeapMemoryUsage().getCommitted(); |
| System.gc(); |
| long committedAfter = memoryBean.getHeapMemoryUsage().getCommitted(); |
| Asserts.assertLessThan(committedAfter, committedBefore); |
| } |
| } finally { |
| workers.shutdown(); |
| workers.awaitTermination(5, TimeUnit.SECONDS); |
| } |
| } |
| |
| private static void allocateToLimit(long limit) { |
| var localKeepAlive = new LinkedList<byte[]>(); |
| |
| long currentAllocation = threadBean.getCurrentThreadAllocatedBytes(); |
| long allocationLimit = currentAllocation + limit; |
| |
| while (currentAllocation < allocationLimit) { |
| // Check roughly every megabyte. |
| for (long j = 0 ; j < 1000; j++) { |
| localKeepAlive.add(new byte[1024]); |
| } |
| currentAllocation = threadBean.getCurrentThreadAllocatedBytes(); |
| } |
| |
| // Add to globalKeepAlive for realease by main thread. |
| globalKeepAlive.add(localKeepAlive); |
| } |
| |
| private static long uptime() { |
| return Duration.between(StartTime, Instant.now()).getSeconds(); |
| } |
| |
| private static void log(String text) { |
| System.out.println(uptime() + "s: " + text); |
| } |
| } |