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Posted to commits@ignite.apache.org by vo...@apache.org on 2016/03/01 10:39:10 UTC
[5/9] ignite git commit: ignite-2333 : Fixed review remarks.
ignite-2333 : Fixed review remarks.
Project: http://git-wip-us.apache.org/repos/asf/ignite/repo
Commit: http://git-wip-us.apache.org/repos/asf/ignite/commit/13b3f4b9
Tree: http://git-wip-us.apache.org/repos/asf/ignite/tree/13b3f4b9
Diff: http://git-wip-us.apache.org/repos/asf/ignite/diff/13b3f4b9
Branch: refs/heads/ignite-2333
Commit: 13b3f4b961c2822cdfc70e1259d0f238d688ab57
Parents: f84d023
Author: Ilya Lantukh <il...@gridgain.com>
Authored: Wed Feb 24 11:42:15 2016 +0300
Committer: Ilya Lantukh <il...@gridgain.com>
Committed: Wed Feb 24 11:42:15 2016 +0300
----------------------------------------------------------------------
.../util/StripedCompositeReadWriteLock.java | 149 ++++++++++++++++---
1 file changed, 130 insertions(+), 19 deletions(-)
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http://git-wip-us.apache.org/repos/asf/ignite/blob/13b3f4b9/modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java
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diff --git a/modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java b/modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java
index ae95f6c..1a8ce2e 100644
--- a/modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java
+++ b/modules/core/src/main/java/org/apache/ignite/internal/util/StripedCompositeReadWriteLock.java
@@ -1,54 +1,140 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
package org.apache.ignite.internal.util;
import org.jetbrains.annotations.NotNull;
import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
- * @author Ilya Lantukh
+ * ReadWriteLock with striping mechanics.
+ * Compared to {@link ReentrantReadWriteLock} it has slightly improved performance of {@link ReadWriteLock#readLock()}
+ * operations at the cost of {@link ReadWriteLock#writeLock()} operations and memory consumption.
+ * It also supports reentrancy semantics like {@link ReentrantReadWriteLock}.
*/
public class StripedCompositeReadWriteLock implements ReadWriteLock {
- private final PaddedReentrantReadWriteLock[] locks;
+ /**
+ * Locks.
+ */
+ private final ReentrantReadWriteLock[] locks;
+ /**
+ * Composite write lock.
+ */
private final CompositeWriteLock compositeWriteLock;
- public StripedCompositeReadWriteLock(int concurrencyLevel) {
- locks = new PaddedReentrantReadWriteLock[concurrencyLevel];
-
- for (int i = 0; i < concurrencyLevel; i++)
+ /**
+ * Atomic field updated for {@link #counter}.
+ */
+ private static final AtomicIntegerFieldUpdater<StripedCompositeReadWriteLock> COUNTER_UPD =
+ AtomicIntegerFieldUpdater.newUpdater(StripedCompositeReadWriteLock.class, "counter");
+
+ /**
+ * Counter of {@link #readLock()} calls.
+ */
+ @SuppressWarnings("UnusedDeclaration")
+ private volatile int counter = 0;
+
+ /**
+ * Creates a new instance with given concurrency level.
+ *
+ * @param concurrencyLvl Number of internal read locks.
+ */
+ public StripedCompositeReadWriteLock(int concurrencyLvl) {
+ locks = new PaddedReentrantReadWriteLock[concurrencyLvl];
+
+ for (int i = 0; i < concurrencyLvl; i++)
locks[i] = new PaddedReentrantReadWriteLock();
compositeWriteLock = new CompositeWriteLock();
}
+ /** {@inheritDoc} */
@NotNull @Override public Lock readLock() {
- int idx = (int)Thread.currentThread().getId() % locks.length;
+ int idx = Math.abs(COUNTER_UPD.getAndIncrement(this) % locks.length);
+
return locks[idx].readLock();
}
+ /** {@inheritDoc} */
@NotNull @Override public Lock writeLock() {
return compositeWriteLock;
}
+ /**
+ * {@inheritDoc}
+ *
+ * Compared to {@link ReentrantReadWriteLock}, this class contains padding to ensure that different instances will
+ * always be located in different CPU cache lines.
+ */
private static class PaddedReentrantReadWriteLock extends ReentrantReadWriteLock {
+ /**
+ *
+ */
private static final long serialVersionUID = 0L;
- long p0, p1, p2, p3, p4, p5, p6, p7;
+ /**
+ * Padding.
+ */
+ private long p0, p1, p2, p3, p4, p5, p6, p7;
}
+ /**
+ * {@inheritDoc}
+ *
+ * Methods of this class will lock all {@link #locks}.
+ */
private class CompositeWriteLock implements Lock {
+ /** {@inheritDoc} */
@Override public void lock() {
+ try {
+ lock(false);
+ } catch (InterruptedException e) {
+ // This should never happen.
+ throw new RuntimeException(e);
+ }
+ }
+
+ /** {@inheritDoc} */
+ @Override public void lockInterruptibly() throws InterruptedException {
+ lock(true);
+ }
+
+ /**
+ * @param interruptibly true if {@link Thread#interrupt()} should be considered.
+ * @throws InterruptedException
+ */
+ private void lock(boolean interruptibly) throws InterruptedException {
int i = 0;
try {
for (; i < locks.length; i++)
- locks[i].writeLock().lock();
+ if (interruptibly)
+ locks[i].writeLock().lockInterruptibly();
+ else
+ locks[i].writeLock().lock();
}
catch (Throwable e) {
for (i--; i >= 0; i--)
@@ -58,11 +144,18 @@ public class StripedCompositeReadWriteLock implements ReadWriteLock {
}
}
- @Override public void lockInterruptibly() throws InterruptedException {
+ /** {@inheritDoc} */
+ @Override public boolean tryLock() {
int i = 0;
+
+ boolean unlock = false;
+
try {
for (; i < locks.length; i++)
- locks[i].writeLock().lockInterruptibly();
+ if (!locks[i].writeLock().tryLock()) {
+ unlock = true;
+ break;
+ }
}
catch (Throwable e) {
for (i--; i >= 0; i--)
@@ -70,19 +163,38 @@ public class StripedCompositeReadWriteLock implements ReadWriteLock {
throw e;
}
+
+ if (unlock) {
+ for (i--; i >= 0; i--)
+ locks[i].writeLock().unlock();
+
+ return false;
+ }
+
+ return true;
}
- @Override public boolean tryLock() {
+ /** {@inheritDoc} */
+ @Override public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
+ long timeLeft = unit.convert(time, TimeUnit.NANOSECONDS);
+
+ long prevTime = System.nanoTime();
+
int i = 0;
boolean unlock = false;
try {
- for (; i < locks.length; i++)
- if (!locks[i].writeLock().tryLock()) {
+ for (; i < locks.length; i++) {
+ if (timeLeft < 0 || !locks[i].writeLock().tryLock(timeLeft, TimeUnit.NANOSECONDS)) {
unlock = true;
break;
}
+
+ long currentTime = System.nanoTime();
+ timeLeft -= (currentTime - prevTime);
+ prevTime = currentTime;
+ }
}
catch (Throwable e) {
for (i--; i >= 0; i--)
@@ -94,23 +206,22 @@ public class StripedCompositeReadWriteLock implements ReadWriteLock {
if (unlock) {
for (i--; i >= 0; i--)
locks[i].writeLock().unlock();
+
return false;
}
return true;
}
- @Override public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
- throw new RuntimeException("Not supported");
- }
-
+ /** {@inheritDoc} */
@Override public void unlock() {
for (int i = locks.length - 1; i >= 0; i--)
locks[i].writeLock().unlock();
}
+ /** {@inheritDoc} */
@NotNull @Override public Condition newCondition() {
- throw new RuntimeException("Not supported");
+ throw new UnsupportedOperationException();
}
}
}