From db7d89a5c960a7a56bb4c7c3b51e8296f066adad Mon Sep 17 00:00:00 2001
From: Simone Bordet <simone.bordet@gmail.com>
Date: Mon, 20 Feb 2017 12:06:08 +0100
Subject: [PATCH] Fixes #1342 - Improve ByteBufferPool scalability.

Replaced Lock+ArrayDeque with ConcurrentLinkedDeque.
---
 .../org/eclipse/jetty/io/ByteBufferPool.java  | 64 +++----------------
 1 file changed, 8 insertions(+), 56 deletions(-)

diff --git a/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java b/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java
index 70fcbb8646c..8f12ee3c8d8 100644
--- a/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java
+++ b/jetty-io/src/main/java/org/eclipse/jetty/io/ByteBufferPool.java
@@ -19,13 +19,11 @@
 package org.eclipse.jetty.io;
 
 import java.nio.ByteBuffer;
-import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Deque;
 import java.util.List;
-import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedDeque;
 import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
 
 import org.eclipse.jetty.util.BufferUtil;
 
@@ -128,8 +126,7 @@ public interface ByteBufferPool
 
     class Bucket
     {
-        private final Lock _lock = new ReentrantLock();
-        private final Queue<ByteBuffer> _queue = new ArrayDeque<>();
+        private final Deque<ByteBuffer> _queue = new ConcurrentLinkedDeque<>();
         private final ByteBufferPool _pool;
         private final int _capacity;
         private final AtomicInteger _space;
@@ -181,72 +178,27 @@ public interface ByteBufferPool
 
         private void queueOffer(ByteBuffer buffer)
         {
-            Lock lock = _lock;
-            lock.lock();
-            try
-            {
-                _queue.offer(buffer);
-            }
-            finally
-            {
-                lock.unlock();
-            }
+            _queue.offerFirst(buffer);
         }
 
         private ByteBuffer queuePoll()
         {
-            Lock lock = _lock;
-            lock.lock();
-            try
-            {
-                return _queue.poll();
-            }
-            finally
-            {
-                lock.unlock();
-            }
+            return _queue.poll();
         }
 
         private void queueClear()
         {
-            Lock lock = _lock;
-            lock.lock();
-            try
-            {
-                _queue.clear();
-            }
-            finally
-            {
-                lock.unlock();
-            }
+            _queue.clear();
         }
 
         boolean isEmpty()
         {
-            Lock lock = _lock;
-            lock.lock();
-            try
-            {
-                return _queue.isEmpty();
-            }
-            finally
-            {
-                lock.unlock();
-            }
+            return _queue.isEmpty();
         }
 
         int size()
         {
-            Lock lock = _lock;
-            lock.lock();
-            try
-            {
-                return _queue.size();
-            }
-            finally
-            {
-                lock.unlock();
-            }
+            return _queue.size();
         }
 
         @Override