Rewrote DirectBufferPool using preallocation strategy (like DirectChannelBufferFactory does)

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

@@ -15,7 +15,6 @@
  */
 package org.jboss.netty.channel.socket.nio;
 
-import java.lang.ref.SoftReference;
 import java.nio.ByteBuffer;
 
 import org.jboss.netty.buffer.ChannelBuffer;
@@ -27,10 +26,9 @@ import org.jboss.netty.buffer.ChannelBuffer;
  */
 final class DirectBufferPool {
 
-    private static final int POOL_SIZE = 4;
+    private static final int preallocatedBufferCapacity = 128 * 1024;
 
-    @SuppressWarnings("unchecked")
+    private ByteBuffer preallocatedBuffer;
-    private final SoftReference<ByteBuffer>[] pool = new SoftReference[POOL_SIZE];
 
     DirectBufferPool() {
         super();
@@ -38,70 +36,43 @@ final class DirectBufferPool {
 
     final ByteBuffer acquire(ChannelBuffer src) {
         ByteBuffer dst = acquire(src.readableBytes());
+        dst.mark();
         src.getBytes(src.readerIndex(), dst);
-        dst.rewind();
+        dst.reset();
         return dst;
     }
 
     final ByteBuffer acquire(int size) {
-        for (int i = 0; i < POOL_SIZE; i ++) {
+        ByteBuffer preallocatedBuffer = this.preallocatedBuffer;
-            SoftReference<ByteBuffer> ref = pool[i];
+        if (preallocatedBuffer == null) {
-            if (ref == null) {
+            if (size < preallocatedBufferCapacity) {
-                continue;
+                return preallocateAndAcquire(size);
-            }
+            } else {
-
+                return ByteBuffer.allocateDirect(size);
-            ByteBuffer buf = ref.get();
-            if (buf == null) {
-                pool[i] = null;
-                continue;
-            }
-
-            if (buf.capacity() < size) {
-                continue;
-            }
-
-            pool[i] = null;
-
-            buf.rewind();
-            buf.limit(size);
-            return buf;
-        }
-
-        ByteBuffer buf = ByteBuffer.allocateDirect(normalizeCapacity(size));
-        buf.limit(size);
-        return buf;
-    }
-
-    final void release(ByteBuffer buffer) {
-        for (int i = 0; i < POOL_SIZE; i ++) {
-            SoftReference<ByteBuffer> ref = pool[i];
-            if (ref == null || ref.get() == null) {
-                pool[i] = new SoftReference<ByteBuffer>(buffer);
-                return;
             }
         }
 
-        // pool is full - replace one
+        if (preallocatedBuffer.remaining() < size) {
-        final int capacity = buffer.capacity();
+            if (size > preallocatedBufferCapacity) {
-        for (int i = 0; i< POOL_SIZE; i ++) {
+                return ByteBuffer.allocateDirect(size);
-            SoftReference<ByteBuffer> ref = pool[i];
+            } else {
-            ByteBuffer pooled = ref.get();
+                return preallocateAndAcquire(size);
-            if (pooled == null) {
-                pool[i] = null;
-                continue;
-            }
-
-            if (pooled.capacity() < capacity) {
-                pool[i] = new SoftReference<ByteBuffer>(buffer);
-                return;
             }
+        } else {
+            int nextPos = preallocatedBuffer.position() + size;
+            ByteBuffer x = preallocatedBuffer.duplicate();
+            preallocatedBuffer.position(nextPos);
+            x.limit(nextPos);
+            return x;
         }
     }
 
-    private static final int normalizeCapacity(int capacity) {
+    private final ByteBuffer preallocateAndAcquire(int size) {
-        // Normalize to multiple of 4096.
+        ByteBuffer preallocatedBuffer = this.preallocatedBuffer =
-        // Strictly speaking, 4096 should be normalized to 4096,
+            ByteBuffer.allocateDirect(preallocatedBufferCapacity);
-        // but it becomes 8192 to keep the calculation simplistic.
+        ByteBuffer x = preallocatedBuffer.duplicate();
-        return (capacity & 0xfffff000) + 0x1000;
+        x.limit(size);
+        preallocatedBuffer.position(size);
+        return x;
     }
 }

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

@@ -109,7 +109,6 @@ class NioDatagramChannel extends AbstractChannel
      */
     MessageEvent currentWriteEvent;
     ByteBuffer currentWriteBuffer;
-    boolean currentWriteBufferIsPooled;
 
     /**
      * Boolean that indicates that write operation is in progress.

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

@@ -521,10 +521,8 @@ class NioDatagramWorker implements Runnable {
                     ChannelBuffer origBuf = (ChannelBuffer) evt.getMessage();
                     if (origBuf.isDirect()) {
                         channel.currentWriteBuffer = buf = origBuf.toByteBuffer();
-                        channel.currentWriteBufferIsPooled = false;
                     } else {
                         channel.currentWriteBuffer = buf = directBufferPool.acquire(origBuf);
-                        channel.currentWriteBufferIsPooled = true;
                     }
                 } else {
                     buf = channel.currentWriteBuffer;
@@ -554,10 +552,6 @@ class NioDatagramWorker implements Runnable {
 
                     if (localWrittenBytes > 0) {
                         // Successful write - proceed to the next message.
-                        if (channel.currentWriteBufferIsPooled) {
-                            directBufferPool.release(buf);
-                        }
-
                         ChannelFuture future = evt.getFuture();
                         channel.currentWriteEvent = null;
                         channel.currentWriteBuffer = null;
@@ -573,9 +567,6 @@ class NioDatagramWorker implements Runnable {
                 } catch (final AsynchronousCloseException e) {
                     // Doesn't need a user attention - ignore.
                 } catch (final Throwable t) {
-                    if (channel.currentWriteBufferIsPooled) {
-                        directBufferPool.release(buf);
-                    }
                     ChannelFuture future = evt.getFuture();
                     channel.currentWriteEvent = null;
                     channel.currentWriteBuffer = null;
@@ -704,7 +695,6 @@ class NioDatagramWorker implements Runnable {
         // Clean up the stale messages in the write buffer.
         synchronized (channel.writeLock) {
             MessageEvent evt = channel.currentWriteEvent;
-            ByteBuffer buf = channel.currentWriteBuffer;
             if (evt != null) {
                 // Create the exception only once to avoid the excessive overhead
                 // caused by fillStackTrace.
@@ -713,14 +703,10 @@ class NioDatagramWorker implements Runnable {
                 } else {
                     cause = new ClosedChannelException();
                 }
-                if (channel.currentWriteBufferIsPooled) {
-                    directBufferPool.release(buf);
-                }
 
                 ChannelFuture future = evt.getFuture();
                 channel.currentWriteEvent = null;
                 channel.currentWriteBuffer = null;
-                buf = null;
                 evt = null;
                 future.setFailure(cause);
                 fireExceptionCaught = true;

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

@@ -72,7 +72,6 @@ class NioSocketChannel extends AbstractChannel
 
     MessageEvent currentWriteEvent;
     ByteBuffer currentWriteBuffer;
-    boolean currentWriteBufferIsPooled;
 
     public NioSocketChannel(
             Channel parent, ChannelFactory factory,

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

@@ -318,6 +318,7 @@ class NioWorker implements Runnable {
         final boolean fromPool = !buffer.isDirect();
         if (fromPool) {
             directBuffer = directBufferPool.acquire(buffer.writableBytes());
+            directBuffer.mark();
         } else {
             directBuffer = buffer.toByteBuffer();
         }
@@ -339,9 +340,9 @@ class NioWorker implements Runnable {
             fireExceptionCaught(channel, t);
         } finally {
             if (fromPool) {
-                directBuffer.flip();
+                directBuffer.limit(directBuffer.position());
+                directBuffer.reset();
                 buffer.writeBytes(directBuffer);
-                directBufferPool.release(directBuffer);
             } else {
                 // no need to copy: directBuffer is just a view to buffer.
                 buffer.writerIndex(buffer.writerIndex() + readBytes);
@@ -463,10 +464,8 @@ class NioWorker implements Runnable {
                     ChannelBuffer origBuf = (ChannelBuffer) evt.getMessage();
                     if (origBuf.isDirect()) {
                         channel.currentWriteBuffer = buf = origBuf.toByteBuffer();
-                        channel.currentWriteBufferIsPooled = false;
                     } else {
                         channel.currentWriteBuffer = buf = directBufferPool.acquire(origBuf);
-                        channel.currentWriteBufferIsPooled = true;
                     }
                 } else {
                     buf = channel.currentWriteBuffer;
@@ -483,10 +482,6 @@ class NioWorker implements Runnable {
 
                     if (!buf.hasRemaining()) {
                         // Successful write - proceed to the next message.
-                        if (channel.currentWriteBufferIsPooled) {
-                            directBufferPool.release(buf);
-                        }
-
                         ChannelFuture future = evt.getFuture();
                         channel.currentWriteEvent = null;
                         channel.currentWriteBuffer = null;
@@ -502,9 +497,6 @@ class NioWorker implements Runnable {
                 } catch (AsynchronousCloseException e) {
                     // Doesn't need a user attention - ignore.
                 } catch (Throwable t) {
-                    if (channel.currentWriteBufferIsPooled) {
-                        directBufferPool.release(buf);
-                    }
                     ChannelFuture future = evt.getFuture();
                     channel.currentWriteEvent = null;
                     channel.currentWriteBuffer = null;
@@ -624,7 +616,6 @@ class NioWorker implements Runnable {
         // Clean up the stale messages in the write buffer.
         synchronized (channel.writeLock) {
             MessageEvent evt = channel.currentWriteEvent;
-            ByteBuffer buf = channel.currentWriteBuffer;
             if (evt != null) {
                 // Create the exception only once to avoid the excessive overhead
                 // caused by fillStackTrace.
@@ -634,14 +625,9 @@ class NioWorker implements Runnable {
                     cause = new ClosedChannelException();
                 }
 
-                if (channel.currentWriteBufferIsPooled) {
-                    directBufferPool.release(buf);
-                }
-
                 ChannelFuture future = evt.getFuture();
                 channel.currentWriteEvent = null;
                 channel.currentWriteBuffer = null;
-                buf = null;
                 evt = null;
                 future.setFailure(cause);
                 fireExceptionCaught = true;