101 lines
3.3 KiB
Java
101 lines
3.3 KiB
Java
/*
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* Copyright (c) 2014, 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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*/
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package rtm;
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import java.util.concurrent.BrokenBarrierException;
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import java.util.concurrent.CyclicBarrier;
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/**
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* To force transactional execution abort due to memory conflict
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* one thread should access memory region from transactional region
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* while another thread should modify the same memory region.
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* Since this scenario is based on the race condition between threads
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* you should not expect some particular amount of aborts.
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*/
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class MemoryConflictProvoker extends AbortProvoker {
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// Following field have to be static in order to avoid escape analysis.
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@SuppressWarnings("UnsuedDeclaration")
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private static int field = 0;
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private static final int INNER_ITERATIONS = 10000;
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private final CyclicBarrier barrier;
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/**
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* This thread will access and modify memory region
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* from outside of the transaction.
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*/
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private final Runnable conflictingThread;
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public MemoryConflictProvoker() {
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this(new Object());
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}
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public MemoryConflictProvoker(Object monitor) {
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super(monitor);
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barrier = new CyclicBarrier(2);
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conflictingThread = () -> {
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try {
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barrier.await();
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} catch (Exception e) {
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throw new RuntimeException(e);
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}
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for (int i = 0; i < MemoryConflictProvoker.INNER_ITERATIONS; i++) {
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MemoryConflictProvoker.field++;
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}
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};
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}
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/**
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* Accesses and modifies memory region from within the transaction.
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*/
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public void transactionalRegion() {
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try {
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barrier.await();
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} catch (InterruptedException | BrokenBarrierException e) {
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throw new RuntimeException(e);
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}
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for (int i = 0; i < MemoryConflictProvoker.INNER_ITERATIONS; i++) {
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synchronized(monitor) {
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MemoryConflictProvoker.field--;
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}
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}
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}
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@Override
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public void forceAbort() {
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try {
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Thread t = new Thread(conflictingThread);
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t.start();
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transactionalRegion();
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t.join();
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} catch (Exception e) {
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throw new RuntimeException(e);
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}
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}
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@Override
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public String getMethodWithLockName() {
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return this.getClass().getName() + "::transactionalRegion";
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}
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}
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