Remove request limit throttle. Move to middleware later.

src/Microsoft.AspNet.Server.WebListener/AwaitableThrottle.cs

@@ -1,89 +0,0 @@
-using System.Collections.Generic;
-using System.Diagnostics.Contracts;
-using System.Runtime.CompilerServices;
-using System.Threading.Tasks;
-
-namespace Microsoft.AspNet.Server.WebListener
-{
-    /// <summary>
-    /// AwaitableThrottle is an awaitable object that acts like a semaphore. The object would wait if more than maxConcurrent number of clients waits on it.
-    /// </summary>
-    internal class AwaitableThrottle
-    {
-        private static readonly TaskAwaiter<bool> CompletedAwaiter = Task.FromResult(true).GetAwaiter();
-
-        private int _maxConcurrent;
-        private readonly object _thislock;
-        private readonly Queue<TaskCompletionSource<bool>> _awaiters;
-
-        private int _count;
-
-        // <param name="maxConcurrent">Maximum number of clients that can wait on this object at the same time.</param>
-        public AwaitableThrottle(int maxConcurrent)
-        {
-            _thislock = new object();
-            _awaiters = new Queue<TaskCompletionSource<bool>>();
-            _maxConcurrent = maxConcurrent;
-        }
-
-        public int MaxConcurrent
-        {
-            get
-            {
-                return _maxConcurrent;
-            }
-            set
-            {
-                Contract.Assert(_maxConcurrent >= 0,
-                    "Behavior of this class is undefined for negative value");
-                // Note:
-                // 1. This setter is non-thread safe. We assumed it doesnt need to be for simplicity sake.
-                // 2. Behavior of this class is not well defined if a negative value is passed in. If it 
-                //    is awaited before any Release() is called, the subsequent Relese() would eagerly
-                //    unblock awaiting thread instead of waiting for _count to reach the negative value specified.
-                _maxConcurrent = value;
-            }
-        }
-
-        public TaskAwaiter<bool> GetAwaiter()
-        {
-            TaskCompletionSource<bool> awaiter;
-
-            lock (_thislock)
-            {
-                if (_count < _maxConcurrent)
-                {
-                    _count++;
-                    return CompletedAwaiter;
-                }
-
-                awaiter = new TaskCompletionSource<bool>();
-                _awaiters.Enqueue(awaiter);
-            }
-
-            return awaiter.Task.GetAwaiter();
-        }
-
-        public void Release()
-        {
-            TaskCompletionSource<bool> completion = null;
-
-            lock (_thislock)
-            {
-                if (_awaiters.Count > 0)
-                {
-                    completion = _awaiters.Dequeue();
-                }
-                else
-                {
-                    _count--;
-                }
-            }
-
-            if (completion != null)
-            {
-                completion.SetResult(true);
-            }
-        }
-    }  
-}

src/Microsoft.AspNet.Server.WebListener/PumpLimits.cs

@@ -18,13 +18,11 @@ namespace Microsoft.AspNet.Server.WebListener
 {
     internal struct PumpLimits
     {
-        internal PumpLimits(int maxAccepts, int maxRequests)
+        internal PumpLimits(int maxAccepts)
         {
             MaxOutstandingAccepts = maxAccepts;
-            MaxOutstandingRequests = maxRequests;
         }
 
         internal readonly int MaxOutstandingAccepts;
-        internal readonly int MaxOutstandingRequests;
     }
 }

src/Microsoft.AspNet.Server.WebListener/WebListenerWrapper.cs

@@ -15,7 +15,6 @@ namespace Microsoft.AspNet.Server.WebListener
     public class WebListenerWrapper : IDisposable
     {
         private static readonly int DefaultMaxAccepts = 5 * Environment.ProcessorCount;
-        private static readonly int DefaultMaxRequests = Int32.MaxValue;
 
         private OwinWebListener _listener;
         private AppFunc _appFunc;
@@ -24,7 +23,6 @@ namespace Microsoft.AspNet.Server.WebListener
         private PumpLimits _pumpLimits;
         private int _acceptorCounts;
         private Action<object> _processRequest;
-        private readonly AwaitableThrottle _requestProcessingThrottle;
 
         // TODO: private IDictionary<string, object> _capabilities;
 
@@ -34,8 +32,7 @@ namespace Microsoft.AspNet.Server.WebListener
             _listener = listener;
 
             _processRequest = new Action<object>(ProcessRequestAsync);
-            _pumpLimits = new PumpLimits(DefaultMaxAccepts, DefaultMaxRequests);
+            _pumpLimits = new PumpLimits(DefaultMaxAccepts);
-            _requestProcessingThrottle = new AwaitableThrottle(DefaultMaxRequests);
         }
 
         internal void Start(AppFunc app, IList<IDictionary<string, object>> addresses,  LoggerFactoryFunc loggerFactory)
@@ -72,10 +69,9 @@ namespace Microsoft.AspNet.Server.WebListener
         /// This controls how many requests the server attempts to process concurrently.
         /// </summary>
         /// <param name="maxAccepts">The maximum number of pending accepts.</param>
-        /// <param name="maxRequests">The maximum number of outstanding requests.</param>
+        public void SetRequestProcessingLimits(int maxAccepts)
-        public void SetRequestProcessingLimits(int maxAccepts, int maxRequests)
         {
-            _pumpLimits = new PumpLimits(maxAccepts, maxRequests);
+            _pumpLimits = new PumpLimits(maxAccepts);
 
             if (_listener.IsListening)
             {
@@ -85,8 +81,6 @@ namespace Microsoft.AspNet.Server.WebListener
 
         private void ActivateRequestProcessingLimits()
         {
-            _requestProcessingThrottle.MaxConcurrent = _pumpLimits.MaxOutstandingRequests;
-
             for (int i = _acceptorCounts; i < _pumpLimits.MaxOutstandingAccepts; i++)
             {
                 ProcessRequestsWorker();
@@ -97,14 +91,11 @@ namespace Microsoft.AspNet.Server.WebListener
         /// Gets the request processing limits.
         /// </summary>
         /// <param name="maxAccepts">The maximum number of pending accepts.</param>
-        /// <param name="maxRequests">The maximum number of outstanding requests.</param>
         [SuppressMessage("Microsoft.Design", "CA1021:AvoidOutParameters", MessageId = "0#", Justification = "By design")]
-        [SuppressMessage("Microsoft.Design", "CA1021:AvoidOutParameters", MessageId = "1#", Justification = "By design")]
+        public void GetRequestProcessingLimits(out int maxAccepts)
-        public void GetRequestProcessingLimits(out int maxAccepts, out int maxRequests)
         {
             PumpLimits limits = _pumpLimits;
             maxAccepts = limits.MaxOutstandingAccepts;
-            maxRequests = limits.MaxOutstandingRequests;
         }
 
         // The message pump.
@@ -116,8 +107,6 @@ namespace Microsoft.AspNet.Server.WebListener
             int workerIndex = Interlocked.Increment(ref _acceptorCounts);
             while (_listener.IsListening && workerIndex <= _pumpLimits.MaxOutstandingAccepts)
             {
-                await _requestProcessingThrottle;
-
                 // Receive a request
                 RequestContext requestContext;
                 try
@@ -139,7 +128,6 @@ namespace Microsoft.AspNet.Server.WebListener
                     // Request processing failed to be queued in threadpool
                     // Log the error message, release throttle and move on
                     LogHelper.LogException(_logger, "ProcessRequestAsync", ex);
-                    _requestProcessingThrottle.Release();
                 }
             }
             Interlocked.Decrement(ref _acceptorCounts);
@@ -152,7 +140,6 @@ namespace Microsoft.AspNet.Server.WebListener
             {
                 try
                 {
-                    // TODO: Make disconnect registration lazy
                     FeatureContext featureContext = new FeatureContext(requestContext);
                     await _appFunc(featureContext.Features).SupressContext();
                     await requestContext.ProcessResponseAsync().SupressContext();
@@ -178,10 +165,6 @@ namespace Microsoft.AspNet.Server.WebListener
                 requestContext.Abort();
                 requestContext.Dispose();
             }
-            finally
-            {
-                _requestProcessingThrottle.Release();
-            }
         }
 
         public void Dispose()