Manually GC direct ByteBuffer that is used by the Worker's on releaseExternalResources() to free up memory asap. See #638

src/main/java/org/jboss/netty/channel/socket/nio/AbstractNioWorker.java

@@ -49,10 +49,11 @@ import org.jboss.netty.channel.socket.Worker;
 import org.jboss.netty.channel.socket.nio.SocketSendBufferPool.SendBuffer;
 import org.jboss.netty.logging.InternalLogger;
 import org.jboss.netty.logging.InternalLoggerFactory;
+import org.jboss.netty.util.ExternalResourceReleasable;
 import org.jboss.netty.util.ThreadRenamingRunnable;
 import org.jboss.netty.util.internal.DeadLockProofWorker;
 
-abstract class AbstractNioWorker implements Worker {
+abstract class AbstractNioWorker implements Worker, ExternalResourceReleasable {
 
 
     private static final AtomicInteger nextId = new AtomicInteger();
@@ -902,6 +903,11 @@ abstract class AbstractNioWorker implements Worker {
         }
     }
 
+
+    public void releaseExternalResources() {
+        sendBufferPool.releaseExternalResources();
+    }
+
     /**
      * Read is called when a Selector has been notified that the underlying channel
      * was something to be read. The channel would previously have registered its interest

src/main/java/org/jboss/netty/channel/socket/nio/AbstractNioWorkerPool.java

@@ -75,6 +75,9 @@ public abstract class AbstractNioWorkerPool<E extends AbstractNioWorker>
 
     public void releaseExternalResources() {
         ExecutorUtil.terminate(workerExecutor);
+        for (AbstractNioWorker worker: workers) {
+            worker.releaseExternalResources();
+        }
     }
 
 }

src/main/java/org/jboss/netty/channel/socket/nio/NioDatagramWorker.java

@@ -110,6 +110,12 @@ public class NioDatagramWorker extends AbstractNioWorker {
     }
 
 
+    @Override
+    public void releaseExternalResources() {
+        super.releaseExternalResources();
+        bufferAllocator.releaseExternalResources();
+    }
+
     @Override
     protected boolean scheduleWriteIfNecessary(final AbstractNioChannel<?> channel) {
         final Thread workerThread = thread;

src/main/java/org/jboss/netty/channel/socket/nio/NioWorker.java

@@ -130,6 +130,12 @@ public class NioWorker extends AbstractNioWorker {
         return false;
     }
 
+    @Override
+    public void releaseExternalResources() {
+        super.releaseExternalResources();
+        recvBufferPool.releaseExternalResources();
+    }
+
     @Override
     protected Runnable createRegisterTask(AbstractNioChannel<?> channel, ChannelFuture future) {
         boolean server = !(channel instanceof NioClientSocketChannel);

src/main/java/org/jboss/netty/channel/socket/nio/SocketReceiveBufferAllocator.java

@@ -17,9 +17,10 @@ package org.jboss.netty.channel.socket.nio;
 
 import java.nio.ByteBuffer;
 
+import org.jboss.netty.util.ExternalResourceReleasable;
 import org.jboss.netty.util.internal.ByteBufferUtil;
 
-final class SocketReceiveBufferAllocator {
+final class SocketReceiveBufferAllocator implements ExternalResourceReleasable {
 
     private ByteBuffer buf;
     private int exceedCount;
@@ -72,4 +73,10 @@ final class SocketReceiveBufferAllocator {
         }
         return q << 10;
     }
+
+    public void releaseExternalResources() {
+        if (buf != null) {
+            ByteBufferUtil.destroy(buf);
+        }
+    }
 }

src/main/java/org/jboss/netty/channel/socket/nio/SocketSendBufferPool.java

@@ -27,8 +27,10 @@ import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.CompositeChannelBuffer;
 import org.jboss.netty.channel.DefaultFileRegion;
 import org.jboss.netty.channel.FileRegion;
+import org.jboss.netty.util.ExternalResourceReleasable;
+import org.jboss.netty.util.internal.ByteBufferUtil;
 
-final class SocketSendBufferPool {
+final class SocketSendBufferPool implements ExternalResourceReleasable {
 
     private static final SendBuffer EMPTY_BUFFER = new EmptySendBuffer();
 
@@ -383,4 +385,10 @@ final class SocketSendBufferPool {
             // Unpooled.
         }
     }
+
+    public void releaseExternalResources() {
+        if (current.buffer != null) {
+            ByteBufferUtil.destroy(current.buffer);
+        }
+    }
 }