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Diffstat (limited to 'java/broker/src/main/java/org/apache/qpid/server/transport/ThreadPoolFilter.java')
| -rw-r--r-- | java/broker/src/main/java/org/apache/qpid/server/transport/ThreadPoolFilter.java | 705 |
1 files changed, 705 insertions, 0 deletions
diff --git a/java/broker/src/main/java/org/apache/qpid/server/transport/ThreadPoolFilter.java b/java/broker/src/main/java/org/apache/qpid/server/transport/ThreadPoolFilter.java new file mode 100644 index 0000000000..bdd27f2d1c --- /dev/null +++ b/java/broker/src/main/java/org/apache/qpid/server/transport/ThreadPoolFilter.java @@ -0,0 +1,705 @@ +/* + * + * 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.qpid.server.transport; + +import java.util.ArrayList; +import java.util.IdentityHashMap; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.Set; + +import org.apache.mina.common.IdleStatus; +import org.apache.mina.common.IoFilterAdapter; +import org.apache.mina.common.IoHandler; +import org.apache.mina.common.IoSession; +import org.apache.mina.util.BlockingQueue; +import org.apache.mina.util.ByteBufferUtil; +import org.apache.mina.util.IdentityHashSet; +import org.apache.mina.util.Queue; +import org.apache.mina.util.Stack; + +/** + * A Thread-pooling filter. This filter forwards {@link IoHandler} events + * to its thread pool. + * <p/> + * This is an implementation of + * <a href="http://deuce.doc.wustl.edu/doc/pspdfs/lf.pdf">Leader/Followers + * thread pool</a> by Douglas C. Schmidt et al. + */ +public class ThreadPoolFilter extends IoFilterAdapter +{ + /** + * Default maximum size of thread pool (2G). + */ + public static final int DEFAULT_MAXIMUM_POOL_SIZE = Integer.MAX_VALUE; + + /** + * Default keep-alive time of thread pool (1 min). + */ + public static final int DEFAULT_KEEP_ALIVE_TIME = 60 * 1000; + + /** + * A queue which contains {@link Integer}s which represents reusable + * thread IDs. {@link Worker} first checks this queue and then + * uses {@link #threadId} when no reusable thread ID is available. + */ + private static final Queue threadIdReuseQueue = new Queue(); + private static int threadId = 0; + + private static int acquireThreadId() + { + synchronized (threadIdReuseQueue) + { + Integer id = (Integer) threadIdReuseQueue.pop(); + if (id == null) + { + return ++ threadId; + } + else + { + return id.intValue(); + } + } + } + + private static void releaseThreadId(int id) + { + synchronized (threadIdReuseQueue) + { + threadIdReuseQueue.push(new Integer(id)); + } + } + + private final String threadNamePrefix; + private final Map buffers = new IdentityHashMap(); + private final BlockingQueue unfetchedSessionBuffers = new BlockingQueue(); + private final Set allSessionBuffers = new IdentityHashSet(); + + private Worker leader; + private final Stack followers = new Stack(); + private final Set allWorkers = new IdentityHashSet(); + + private int maximumPoolSize = DEFAULT_MAXIMUM_POOL_SIZE; + private int keepAliveTime = DEFAULT_KEEP_ALIVE_TIME; + + private boolean shuttingDown; + + private int poolSize; + private final Object poolSizeLock = new Object(); + + /** + * Creates a new instance of this filter with default thread pool settings. + */ + public ThreadPoolFilter() + { + this("IoThreadPool"); + } + + /** + * Creates a new instance of this filter with the specified thread name prefix + * and other default settings. + * + * @param threadNamePrefix the prefix of the thread names this pool will create. + */ + public ThreadPoolFilter(String threadNamePrefix) + { + if (threadNamePrefix == null) + { + throw new NullPointerException("threadNamePrefix"); + } + threadNamePrefix = threadNamePrefix.trim(); + if (threadNamePrefix.length() == 0) + { + throw new IllegalArgumentException("threadNamePrefix is empty."); + } + this.threadNamePrefix = threadNamePrefix; + } + + public String getThreadNamePrefix() + { + return threadNamePrefix; + } + + public int getPoolSize() + { + synchronized (poolSizeLock) + { + return poolSize; + } + } + + public int getMaximumPoolSize() + { + return maximumPoolSize; + } + + public int getKeepAliveTime() + { + return keepAliveTime; + } + + public void setMaximumPoolSize(int maximumPoolSize) + { + if (maximumPoolSize <= 0) + { + throw new IllegalArgumentException(); + } + this.maximumPoolSize = maximumPoolSize; + } + + public void setKeepAliveTime(int keepAliveTime) + { + this.keepAliveTime = keepAliveTime; + } + + public void init() + { + shuttingDown = false; + leader = new Worker(); + leader.start(); + leader.lead(); + } + + public void destroy() + { + shuttingDown = true; + int expectedPoolSize = 0; + while (getPoolSize() != expectedPoolSize) + { + List allWorkers; + synchronized (poolSizeLock) + { + allWorkers = new ArrayList(this.allWorkers); + } + + // You may not interrupt the current thread. + if (allWorkers.remove(Thread.currentThread())) + { + expectedPoolSize = 1; + } + + for (Iterator i = allWorkers.iterator(); i.hasNext();) + { + Worker worker = (Worker) i.next(); + while (worker.isAlive()) + { + worker.interrupt(); + try + { + // This timeout will help us from + // infinite lock-up and interrupt workers again. + worker.join(100); + } + catch (InterruptedException e) + { + } + } + } + } + + this.allSessionBuffers.clear(); + this.unfetchedSessionBuffers.clear(); + this.buffers.clear(); + this.followers.clear(); + this.leader = null; + } + + private void increasePoolSize(Worker worker) + { + synchronized (poolSizeLock) + { + poolSize++; + allWorkers.add(worker); + } + } + + private void decreasePoolSize(Worker worker) + { + synchronized (poolSizeLock) + { + poolSize--; + allWorkers.remove(worker); + } + } + + private void fireEvent(NextFilter nextFilter, IoSession session, + EventType type, Object data) + { + final BlockingQueue unfetchedSessionBuffers = this.unfetchedSessionBuffers; + final Set allSessionBuffers = this.allSessionBuffers; + final Event event = new Event(type, nextFilter, data); + + synchronized (unfetchedSessionBuffers) + { + final SessionBuffer buf = getSessionBuffer(session); + final Queue eventQueue = buf.eventQueue; + + synchronized (buf) + { + eventQueue.push(event); + } + + if (!allSessionBuffers.contains(buf)) + { + allSessionBuffers.add(buf); + unfetchedSessionBuffers.push(buf); + } + } + } + + /** + * Implement this method to fetch (or pop) a {@link SessionBuffer} from + * the given <tt>unfetchedSessionBuffers</tt>. The default implementation + * simply pops the buffer from it. You could prioritize the fetch order. + * + * @return A non-null {@link SessionBuffer} + */ + protected SessionBuffer fetchSessionBuffer(Queue unfetchedSessionBuffers) + { + return (SessionBuffer) unfetchedSessionBuffers.pop(); + } + + private SessionBuffer getSessionBuffer(IoSession session) + { + final Map buffers = this.buffers; + SessionBuffer buf = (SessionBuffer) buffers.get(session); + if (buf == null) + { + synchronized (buffers) + { + buf = (SessionBuffer) buffers.get(session); + if (buf == null) + { + buf = new SessionBuffer(session); + buffers.put(session, buf); + } + } + } + return buf; + } + + private void removeSessionBuffer(SessionBuffer buf) + { + final Map buffers = this.buffers; + final IoSession session = buf.session; + synchronized (buffers) + { + buffers.remove(session); + } + } + + protected static class SessionBuffer + { + private final IoSession session; + + private final Queue eventQueue = new Queue(); + + private SessionBuffer(IoSession session) + { + this.session = session; + } + + public IoSession getSession() + { + return session; + } + + public Queue getEventQueue() + { + return eventQueue; + } + } + + private class Worker extends Thread + { + private final int id; + private final Object promotionLock = new Object(); + private boolean dead; + + private Worker() + { + int id = acquireThreadId(); + this.id = id; + this.setName(threadNamePrefix + '-' + id); + increasePoolSize(this); + } + + public boolean lead() + { + final Object promotionLock = this.promotionLock; + synchronized (promotionLock) + { + if (dead) + { + return false; + } + + leader = this; + promotionLock.notify(); + } + + return true; + } + + public void run() + { + for (; ;) + { + if (!waitForPromotion()) + { + break; + } + + SessionBuffer buf = fetchBuffer(); + giveUpLead(); + if (buf == null) + { + break; + } + + processEvents(buf); + follow(); + releaseBuffer(buf); + } + + decreasePoolSize(this); + releaseThreadId(id); + } + + private SessionBuffer fetchBuffer() + { + BlockingQueue unfetchedSessionBuffers = ThreadPoolFilter.this.unfetchedSessionBuffers; + synchronized (unfetchedSessionBuffers) + { + while (!shuttingDown) + { + try + { + unfetchedSessionBuffers.waitForNewItem(); + } + catch (InterruptedException e) + { + continue; + } + + return ThreadPoolFilter.this.fetchSessionBuffer(unfetchedSessionBuffers); + } + } + + return null; + } + + private void processEvents(SessionBuffer buf) + { + final IoSession session = buf.session; + final Queue eventQueue = buf.eventQueue; + for (; ;) + { + Event event; + synchronized (buf) + { + event = (Event) eventQueue.pop(); + if (event == null) + { + break; + } + } + processEvent(event.getNextFilter(), session, + event.getType(), event.getData()); + } + } + + private void follow() + { + final Object promotionLock = this.promotionLock; + final Stack followers = ThreadPoolFilter.this.followers; + synchronized (promotionLock) + { + if (this != leader) + { + synchronized (followers) + { + followers.push(this); + } + } + } + } + + private void releaseBuffer(SessionBuffer buf) + { + final BlockingQueue unfetchedSessionBuffers = ThreadPoolFilter.this.unfetchedSessionBuffers; + final Set allSessionBuffers = ThreadPoolFilter.this.allSessionBuffers; + final Queue eventQueue = buf.eventQueue; + + synchronized (unfetchedSessionBuffers) + { + if (eventQueue.isEmpty()) + { + allSessionBuffers.remove(buf); + removeSessionBuffer(buf); + } + else + { + unfetchedSessionBuffers.push(buf); + } + } + } + + private boolean waitForPromotion() + { + final Object promotionLock = this.promotionLock; + + long startTime = System.currentTimeMillis(); + long currentTime = System.currentTimeMillis(); + + synchronized (promotionLock) + { + while (this != leader && !shuttingDown) + { + // Calculate remaining keep-alive time + int keepAliveTime = getKeepAliveTime(); + if (keepAliveTime > 0) + { + keepAliveTime -= (currentTime - startTime); + } + else + { + keepAliveTime = Integer.MAX_VALUE; + } + + // Break the loop if there's no remaining keep-alive time. + if (keepAliveTime <= 0) + { + break; + } + + // Wait for promotion + try + { + promotionLock.wait(keepAliveTime); + } + catch (InterruptedException e) + { + } + + // Update currentTime for the next iteration + currentTime = System.currentTimeMillis(); + } + + boolean timeToLead = this == leader && !shuttingDown; + + if (!timeToLead) + { + // time to die + synchronized (followers) + { + followers.remove(this); + } + + // Mark as dead explicitly when we've got promotionLock. + dead = true; + } + + return timeToLead; + } + } + + private void giveUpLead() + { + final Stack followers = ThreadPoolFilter.this.followers; + Worker worker; + do + { + synchronized (followers) + { + worker = (Worker) followers.pop(); + } + + if (worker == null) + { + // Increase the number of threads if we + // are not shutting down and we can increase the number. + if (!shuttingDown + && getPoolSize() < getMaximumPoolSize()) + { + worker = new Worker(); + worker.lead(); + worker.start(); + } + + // This loop should end because: + // 1) lead() is called already, + // 2) or it is shutting down and there's no more threads left. + break; + } + } + while (!worker.lead()); + } + } + + protected static class EventType + { + public static final EventType OPENED = new EventType("OPENED"); + + public static final EventType CLOSED = new EventType("CLOSED"); + + public static final EventType READ = new EventType("READ"); + + public static final EventType WRITTEN = new EventType("WRITTEN"); + + public static final EventType RECEIVED = new EventType("RECEIVED"); + + public static final EventType SENT = new EventType("SENT"); + + public static final EventType IDLE = new EventType("IDLE"); + + public static final EventType EXCEPTION = new EventType("EXCEPTION"); + + private final String value; + + private EventType(String value) + { + this.value = value; + } + + public String toString() + { + return value; + } + } + + protected static class Event + { + private final EventType type; + private final NextFilter nextFilter; + private final Object data; + + public Event(EventType type, NextFilter nextFilter, Object data) + { + this.type = type; + this.nextFilter = nextFilter; + this.data = data; + } + + public Object getData() + { + return data; + } + + + public NextFilter getNextFilter() + { + return nextFilter; + } + + + public EventType getType() + { + return type; + } + } + + public void sessionCreated(NextFilter nextFilter, IoSession session) + { + nextFilter.sessionCreated(session); + } + + public void sessionOpened(NextFilter nextFilter, + IoSession session) + { + fireEvent(nextFilter, session, EventType.OPENED, null); + } + + public void sessionClosed(NextFilter nextFilter, + IoSession session) + { + fireEvent(nextFilter, session, EventType.CLOSED, null); + } + + public void sessionIdle(NextFilter nextFilter, + IoSession session, IdleStatus status) + { + fireEvent(nextFilter, session, EventType.IDLE, status); + } + + public void exceptionCaught(NextFilter nextFilter, + IoSession session, Throwable cause) + { + fireEvent(nextFilter, session, EventType.EXCEPTION, cause); + } + + public void messageReceived(NextFilter nextFilter, + IoSession session, Object message) + { + ByteBufferUtil.acquireIfPossible(message); + fireEvent(nextFilter, session, EventType.RECEIVED, message); + } + + public void messageSent(NextFilter nextFilter, + IoSession session, Object message) + { + ByteBufferUtil.acquireIfPossible(message); + fireEvent(nextFilter, session, EventType.SENT, message); + } + + protected void processEvent(NextFilter nextFilter, + IoSession session, EventType type, + Object data) + { + if (type == EventType.RECEIVED) + { + nextFilter.messageReceived(session, data); + ByteBufferUtil.releaseIfPossible(data); + } + else if (type == EventType.SENT) + { + nextFilter.messageSent(session, data); + ByteBufferUtil.releaseIfPossible(data); + } + else if (type == EventType.EXCEPTION) + { + nextFilter.exceptionCaught(session, (Throwable) data); + } + else if (type == EventType.IDLE) + { + nextFilter.sessionIdle(session, (IdleStatus) data); + } + else if (type == EventType.OPENED) + { + nextFilter.sessionOpened(session); + } + else if (type == EventType.CLOSED) + { + nextFilter.sessionClosed(session); + } + } + + public void filterWrite(NextFilter nextFilter, IoSession session, WriteRequest writeRequest) + { + nextFilter.filterWrite(session, writeRequest); + } + + public void filterClose(NextFilter nextFilter, IoSession session) throws Exception + { + nextFilter.filterClose(session); + } +} |