/*
* Copyright 2011 The Netty Project
*
* The Netty Project 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.jboss.netty.handler.execution;
import java.lang.reflect.Method;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelState;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.WriteCompletionEvent;
import org.jboss.netty.logging.InternalLogger;
import org.jboss.netty.logging.InternalLoggerFactory;
import org.jboss.netty.util.DefaultObjectSizeEstimator;
import org.jboss.netty.util.ObjectSizeEstimator;
import org.jboss.netty.util.internal.ConcurrentIdentityHashMap;
import org.jboss.netty.util.internal.QueueFactory;
import org.jboss.netty.util.internal.SharedResourceMisuseDetector;
/**
* A {@link ThreadPoolExecutor} which blocks the task submission when there's
* too many tasks in the queue. Both per-{@link Channel} and per-{@link Executor}
* limitation can be applied.
* <p>
* When a task (i.e. {@link Runnable}) is submitted,
* {@link MemoryAwareThreadPoolExecutor} calls {@link ObjectSizeEstimator#estimateSize(Object)}
* to get the estimated size of the task in bytes to calculate the amount of
* memory occupied by the unprocessed tasks.
* <p>
* If the total size of the unprocessed tasks exceeds either per-{@link Channel}
* or per-{@link Executor} threshold, any further {@link #execute(Runnable)}
* call will block until the tasks in the queue are processed so that the total
* size goes under the threshold.
*
* <h3>Using an alternative task size estimation strategy</h3>
*
* Although the default implementation does its best to guess the size of an
* object of unknown type, it is always good idea to to use an alternative
* {@link ObjectSizeEstimator} implementation instead of the
* {@link DefaultObjectSizeEstimator} to avoid incorrect task size calculation,
* especially when:
* <ul>
* <li>you are using {@link MemoryAwareThreadPoolExecutor} independently from
* {@link ExecutionHandler},</li>
* <li>you are submitting a task whose type is not {@link ChannelEventRunnable}, or</li>
* <li>the message type of the {@link MessageEvent} in the {@link ChannelEventRunnable}
* is not {@link ChannelBuffer}.</li>
* </ul>
* Here is an example that demonstrates how to implement an {@link ObjectSizeEstimator}
* which understands a user-defined object:
* <pre>
* public class MyRunnable implements {@link Runnable} {
*
* <b>private final byte[] data;</b>
*
* public MyRunnable(byte[] data) {
* this.data = data;
* }
*
* public void run() {
* // Process 'data' ..
* }
* }
*
* public class MyObjectSizeEstimator extends {@link DefaultObjectSizeEstimator} {
*
* {@literal @Override}
* public int estimateSize(Object o) {
* if (<b>o instanceof MyRunnable</b>) {
* <b>return ((MyRunnable) o).data.length + 8;</b>
* }
* return super.estimateSize(o);
* }
* }
*
* {@link ThreadPoolExecutor} pool = new {@link MemoryAwareThreadPoolExecutor}(
* 16, 65536, 1048576, 30, {@link TimeUnit}.SECONDS,
* <b>new MyObjectSizeEstimator()</b>,
* {@link Executors}.defaultThreadFactory());
*
* <b>pool.execute(new MyRunnable(data));</b>
* </pre>
*
* <h3>Event execution order</h3>
*
* Please note that this executor does not maintain the order of the
* {@link ChannelEvent}s for the same {@link Channel}. For example,
* you can even receive a {@code "channelClosed"} event before a
* {@code "messageReceived"} event, as depicted by the following diagram.
*
* For example, the events can be processed as depicted below:
*
* <pre>
* --------------------------------> Timeline -------------------------------->
*
* Thread X: --- Channel A (Event 2) --- Channel A (Event 1) --------------------------->
*
* Thread Y: --- Channel A (Event 3) --- Channel B (Event 2) --- Channel B (Event 3) --->
*
* Thread Z: --- Channel B (Event 1) --- Channel B (Event 4) --- Channel A (Event 4) --->
* </pre>
*
* To maintain the event order, you must use {@link OrderedMemoryAwareThreadPoolExecutor}.
*
* @apiviz.has org.jboss.netty.util.ObjectSizeEstimator oneway - -
* @apiviz.has org.jboss.netty.handler.execution.ChannelEventRunnable oneway - - executes
*/
public class MemoryAwareThreadPoolExecutor extends ThreadPoolExecutor {
private static final InternalLogger logger =
InternalLoggerFactory.getInstance(MemoryAwareThreadPoolExecutor.class);
private static final SharedResourceMisuseDetector misuseDetector =
new SharedResourceMisuseDetector(MemoryAwareThreadPoolExecutor.class);
private volatile Settings settings;
private final ConcurrentMap<Channel, AtomicLong> channelCounters =
new ConcurrentIdentityHashMap<Channel, AtomicLong>();
private final Limiter totalLimiter;
/**
* Creates a new instance.
*
* @param corePoolSize the maximum number of active threads
* @param maxChannelMemorySize the maximum total size of the queued events per channel.
* Specify {@code 0} to disable.
* @param maxTotalMemorySize the maximum total size of the queued events for this pool
* Specify {@code 0} to disable.
*/
public MemoryAwareThreadPoolExecutor(
int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize) {
this(corePoolSize, maxChannelMemorySize, maxTotalMemorySize, 30, TimeUnit.SECONDS);
}
/**
* Creates a new instance.
*
* @param corePoolSize the maximum number of active threads
* @param maxChannelMemorySize the maximum total size of the queued events per channel.
* Specify {@code 0} to disable.
* @param maxTotalMemorySize the maximum total size of the queued events for this pool
* Specify {@code 0} to disable.
* @param keepAliveTime the amount of time for an inactive thread to shut itself down
* @param unit the {@link TimeUnit} of {@code keepAliveTime}
*/
public MemoryAwareThreadPoolExecutor(
int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize,
long keepAliveTime, TimeUnit unit) {
this(corePoolSize, maxChannelMemorySize, maxTotalMemorySize, keepAliveTime, unit, Executors.defaultThreadFactory());
}
/**
* Creates a new instance.
*
* @param corePoolSize the maximum number of active threads
* @param maxChannelMemorySize the maximum total size of the queued events per channel.
* Specify {@code 0} to disable.
* @param maxTotalMemorySize the maximum total size of the queued events for this pool
* Specify {@code 0} to disable.
* @param keepAliveTime the amount of time for an inactive thread to shut itself down
* @param unit the {@link TimeUnit} of {@code keepAliveTime}
* @param threadFactory the {@link ThreadFactory} of this pool
*/
public MemoryAwareThreadPoolExecutor(
int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize,
long keepAliveTime, TimeUnit unit, ThreadFactory threadFactory) {
this(corePoolSize, maxChannelMemorySize, maxTotalMemorySize, keepAliveTime, unit, new DefaultObjectSizeEstimator(), threadFactory);
}
/**
* Creates a new instance.
*
* @param corePoolSize the maximum number of active threads
* @param maxChannelMemorySize the maximum total size of the queued events per channel.
* Specify {@code 0} to disable.
* @param maxTotalMemorySize the maximum total size of the queued events for this pool
* Specify {@code 0} to disable.
* @param keepAliveTime the amount of time for an inactive thread to shut itself down
* @param unit the {@link TimeUnit} of {@code keepAliveTime}
* @param threadFactory the {@link ThreadFactory} of this pool
* @param objectSizeEstimator the {@link ObjectSizeEstimator} of this pool
*/
public MemoryAwareThreadPoolExecutor(
int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize,
long keepAliveTime, TimeUnit unit, ObjectSizeEstimator objectSizeEstimator,
ThreadFactory threadFactory) {
super(corePoolSize, corePoolSize, keepAliveTime, unit,
QueueFactory.createQueue(Runnable.class), threadFactory, new NewThreadRunsPolicy());
if (objectSizeEstimator == null) {
throw new NullPointerException("objectSizeEstimator");
}
if (maxChannelMemorySize < 0) {
throw new IllegalArgumentException(
"maxChannelMemorySize: " + maxChannelMemorySize);
}
if (maxTotalMemorySize < 0) {
throw new IllegalArgumentException(
"maxTotalMemorySize: " + maxTotalMemorySize);
}
// Call allowCoreThreadTimeOut(true) using reflection
// because it is not supported in Java 5.
try {
Method m = getClass().getMethod("allowCoreThreadTimeOut", new Class[] { boolean.class });
m.invoke(this, Boolean.TRUE);
} catch (Throwable t) {
// Java 5
logger.debug(
"ThreadPoolExecutor.allowCoreThreadTimeOut() is not " +
"supported in this platform.");
}
settings = new Settings(
objectSizeEstimator, maxChannelMemorySize);
if (maxTotalMemorySize == 0) {
totalLimiter = null;
} else {
totalLimiter = new Limiter(maxTotalMemorySize);
}
// Misuse check
misuseDetector.increase();
}
@Override
protected void terminated() {
super.terminated();
misuseDetector.decrease();
}
/**
* Returns the {@link ObjectSizeEstimator} of this pool.
*/
public ObjectSizeEstimator getObjectSizeEstimator() {
return settings.objectSizeEstimator;
}
/**
* Sets the {@link ObjectSizeEstimator} of this pool.
*/
public void setObjectSizeEstimator(ObjectSizeEstimator objectSizeEstimator) {
if (objectSizeEstimator == null) {
throw new NullPointerException("objectSizeEstimator");
}
settings = new Settings(
objectSizeEstimator,
settings.maxChannelMemorySize);
}
/**
* Returns the maximum total size of the queued events per channel.
*/
public long getMaxChannelMemorySize() {
return settings.maxChannelMemorySize;
}
/**
* Sets the maximum total size of the queued events per channel.
* Specify {@code 0} to disable.
*/
public void setMaxChannelMemorySize(long maxChannelMemorySize) {
if (maxChannelMemorySize < 0) {
throw new IllegalArgumentException(
"maxChannelMemorySize: " + maxChannelMemorySize);
}
if (getTaskCount() > 0) {
throw new IllegalStateException(
"can't be changed after a task is executed");
}
settings = new Settings(
settings.objectSizeEstimator,
maxChannelMemorySize);
}
/**
* Returns the maximum total size of the queued events for this pool.
*/
public long getMaxTotalMemorySize() {
return totalLimiter.limit;
}
/**
* @deprecated <tt>maxTotalMemorySize</tt> is not modifiable anymore.
*/
@Deprecated
public void setMaxTotalMemorySize(long maxTotalMemorySize) {
if (maxTotalMemorySize < 0) {
throw new IllegalArgumentException(
"maxTotalMemorySize: " + maxTotalMemorySize);
}
if (getTaskCount() > 0) {
throw new IllegalStateException(
"can't be changed after a task is executed");
}
}
@Override
public void execute(Runnable command) {
if (command instanceof ChannelDownstreamEventRunnable) {
throw new RejectedExecutionException("command must be enclosed with an upstream event.");
}
if (!(command instanceof ChannelEventRunnable)) {
command = new MemoryAwareRunnable(command);
}
increaseCounter(command);
doExecute(command);
}
/**
* Put the actual execution logic here. The default implementation simply
* calls {@link #doUnorderedExecute(Runnable)}.
*/
protected void doExecute(Runnable task) {
doUnorderedExecute(task);
}
/**
* Executes the specified task without maintaining the event order.
*/
protected final void doUnorderedExecute(Runnable task) {
super.execute(task);
}
@Override
public boolean remove(Runnable task) {
boolean removed = super.remove(task);
if (removed) {
decreaseCounter(task);
}
return removed;
}
@Override
protected void beforeExecute(Thread t, Runnable r) {
super.beforeExecute(t, r);
decreaseCounter(r);
}
protected void increaseCounter(Runnable task) {
if (!shouldCount(task)) {
return;
}
Settings settings = this.settings;
long maxChannelMemorySize = settings.maxChannelMemorySize;
int increment = settings.objectSizeEstimator.estimateSize(task);
if (task instanceof ChannelEventRunnable) {
ChannelEventRunnable eventTask = (ChannelEventRunnable) task;
eventTask.estimatedSize = increment;
Channel channel = eventTask.getEvent().getChannel();
long channelCounter = getChannelCounter(channel).addAndGet(increment);
//System.out.println("IC: " + channelCounter + ", " + increment);
if (maxChannelMemorySize != 0 && channelCounter >= maxChannelMemorySize && channel.isOpen()) {
if (channel.isReadable()) {
//System.out.println("UNREADABLE");
ChannelHandlerContext ctx = eventTask.getContext();
if (ctx.getHandler() instanceof ExecutionHandler) {
// readSuspended = true;
ctx.setAttachment(Boolean.TRUE);
}
channel.setReadable(false);
}
}
} else {
((MemoryAwareRunnable) task).estimatedSize = increment;
}
if (totalLimiter != null) {
totalLimiter.increase(increment);
}
}
protected void decreaseCounter(Runnable task) {
if (!shouldCount(task)) {
return;
}
Settings settings = this.settings;
long maxChannelMemorySize = settings.maxChannelMemorySize;
int increment;
if (task instanceof ChannelEventRunnable) {
increment = ((ChannelEventRunnable) task).estimatedSize;
} else {
increment = ((MemoryAwareRunnable) task).estimatedSize;
}
if (totalLimiter != null) {
totalLimiter.decrease(increment);
}
if (task instanceof ChannelEventRunnable) {
ChannelEventRunnable eventTask = (ChannelEventRunnable) task;
Channel channel = eventTask.getEvent().getChannel();
long channelCounter = getChannelCounter(channel).addAndGet(-increment);
//System.out.println("DC: " + channelCounter + ", " + increment);
if (maxChannelMemorySize != 0 && channelCounter < maxChannelMemorySize && channel.isOpen()) {
if (!channel.isReadable()) {
//System.out.println("READABLE");
ChannelHandlerContext ctx = eventTask.getContext();
if (ctx.getHandler() instanceof ExecutionHandler) {
// check if the attachment was set as this means that we suspend the channel from reads. This only works when
// this pool is used with ExecutionHandler but I guess thats good enough for us.
//
// See #215
if (ctx.getAttachment() != null) {
// readSuspended = false;
ctx.setAttachment(null);
channel.setReadable(true);
}
} else {
channel.setReadable(true);
}
}
}
}
}
private AtomicLong getChannelCounter(Channel channel) {
AtomicLong counter = channelCounters.get(channel);
if (counter == null) {
counter = new AtomicLong();
AtomicLong oldCounter = channelCounters.putIfAbsent(channel, counter);
if (oldCounter != null) {
counter = oldCounter;
}
}
// Remove the entry when the channel closes.
if (!channel.isOpen()) {
channelCounters.remove(channel);
}
return counter;
}
/**
* Returns {@code true} if and only if the specified {@code task} should
* be counted to limit the global and per-channel memory consumption.
* To override this method, you must call {@code super.shouldCount()} to
* make sure important tasks are not counted.
*/
protected boolean shouldCount(Runnable task) {
if (task instanceof ChannelUpstreamEventRunnable) {
ChannelUpstreamEventRunnable r = (ChannelUpstreamEventRunnable) task;
ChannelEvent e = r.getEvent();
if (e instanceof WriteCompletionEvent) {
return false;
} else if (e instanceof ChannelStateEvent) {
if (((ChannelStateEvent) e).getState() == ChannelState.INTEREST_OPS) {
return false;
}
}
}
return true;
}
private static final class Settings {
final ObjectSizeEstimator objectSizeEstimator;
final long maxChannelMemorySize;
Settings(ObjectSizeEstimator objectSizeEstimator,
long maxChannelMemorySize) {
this.objectSizeEstimator = objectSizeEstimator;
this.maxChannelMemorySize = maxChannelMemorySize;
}
}
private static final class NewThreadRunsPolicy implements RejectedExecutionHandler {
public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
try {
final Thread t = new Thread(r, "Temporary task executor");
t.start();
} catch (Throwable e) {
throw new RejectedExecutionException(
"Failed to start a new thread", e);
}
}
}
private static final class MemoryAwareRunnable implements Runnable {
final Runnable task;
int estimatedSize;
MemoryAwareRunnable(Runnable task) {
this.task = task;
}
public void run() {
task.run();
}
}
private static class Limiter {
final long limit;
private long counter;
private int waiters;
Limiter(long limit) {
this.limit = limit;
}
synchronized void increase(long amount) {
while (counter >= limit) {
waiters ++;
try {
wait();
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
} finally {
waiters --;
}
}
counter += amount;
}
synchronized void decrease(long amount) {
counter -= amount;
if (counter < limit && waiters > 0) {
notifyAll();
}
}
}
}