V1.1 update (#2)

V1.1 update

Author: Jinhuafei

src/SessionStateModule/AppSettings.cs

@@ -22,6 +22,12 @@ private static void LoadSettings(NameValueCollection appSettings)
             {
                 _requestQueueLimitPerSession = DefaultRequestQueueLimitPerSession;
             }
+
+            //
+            // AllowConcurrentRequests
+            //
+            string allowConcurrentRequestPerSession = appSettings["aspnet:AllowConcurrentRequestsPerSession"];
+            bool.TryParse(allowConcurrentRequestPerSession, out _allowConcurrentRequestsPerSession);
         }
 
         private static void EnsureSettingsLoaded()
@@ -62,5 +68,15 @@ public static int RequestQueueLimitPerSession
                 return _requestQueueLimitPerSession;
             }
         }
+
+        private static bool _allowConcurrentRequestsPerSession = false;
+        public static bool AllowConcurrentRequestsPerSession
+        {
+            get
+            {
+                EnsureSettingsLoaded();
+                return _allowConcurrentRequestsPerSession;
+            }
+        }
     }
 }

src/SessionStateModule/InProcSessionStateStoreAsync.cs

@@ -161,36 +161,7 @@ public override Task RemoveItemAsync(
                 throw new ArgumentException(SR.Session_id_too_long);
             }
 
-            var lockCookie = (int)lockId;
-            var state = (InProcSessionState)s_store.Get(id);
-
-            if(state != null)
-            {
-                bool lockTaken = false;
-
-                try
-                {
-                    state.SpinLock.Enter(ref lockTaken);
-
-                    // Only remove the item if we are the owner
-                    if(!state.Locked || state.LockCookie != lockCookie)
-                    {
-                        return Task.CompletedTask;
-                    }
-
-                    // prevent overwriting when we drop the lock
-                    state.LockCookie = 0;
-                }
-                finally
-                {
-                    if(lockTaken)
-                    {
-                        state.SpinLock.Exit();
-                    }
-                }
-
-                s_store.Remove(id);
-            }
+            s_store.Remove(id);
 
             return Task.CompletedTask;
         }
@@ -253,11 +224,6 @@ public override Task SetAndReleaseItemExclusiveAsync(
                 try
                 {
                     currentState.SpinLock.Enter(ref lockTaken);
-                    // Only set the state if we are the owner
-                    if(!currentState.Locked || currentState.LockCookie != lockCookie)
-                    {
-                        return Task.CompletedTask;
-                    }
 
                     // we can change the state in place if the timeout hasn't changed
                     if(currentState.Timeout == item.Timeout)
@@ -278,14 +244,7 @@ Please note that the item itself should not expire between now and
                            updated its expiry time.
                         */
                         currentState.Flags |= (int)SessionStateItemFlags.IgnoreCacheItemRemoved;
-
-                        /* By setting _lockCookie to 0, we prevent an overwriting by ReleaseExclusive 
-                           when we drop the lock.
-                           The scenario can happen if another request is polling and trying to prempt
-                           the lock we have on the item.
-                        */
                         lockCookieForInsert = lockCookie;
-                        currentState.LockCookie = 0;
                     }
                 }
                 finally
@@ -346,12 +305,7 @@ private Task<GetItemResult> DoGetAsync(HttpContextBase context, string id, bool
             SessionStateActions actionFlags;
 
             var item = DoGet(context, id, exclusive, out locked, out lockAge, out lockId, out actionFlags);
-            GetItemResult result = null;
-
-            if (item != null)
-            {
-                result = new GetItemResult(item, locked, lockAge, lockId, actionFlags);
-            }
+            GetItemResult result = new GetItemResult(item, locked, lockAge, lockId, actionFlags);
 
             return Task.FromResult<GetItemResult>(result);
         }
@@ -472,7 +426,7 @@ private void InsertToCache(string key, InProcSessionState value)
                 RemovedCallback = _callback,
                 Priority = CacheItemPriority.NotRemovable
             };
-            s_store.Add(key, value, cachePolicy);
+            s_store.Set(key, value, cachePolicy);
         }
 
         private SessionStateStoreData CreateLegitStoreData(

src/SessionStateModule/SessionStateModuleAsync.cs

@@ -576,7 +576,11 @@ private async Task CompleteAcquireStateAsync(HttpContext context)
                     OnStart(EventArgs.Empty);
                 }
 
-                RegisterEnsureStateStoreItemLocked();
+                // lock free session doesn't need this
+                if(!AppSettings.AllowConcurrentRequestsPerSession)
+                {
+                    RegisterEnsureStateStoreItemLocked();
+                }
             }
             finally
             {
@@ -653,7 +657,7 @@ private async Task GetSessionStateItemAsync()
 
                     Debug.Assert(_rqId != null, "_rqId != null");
 
-                    if (_rqReadonly)
+                    if (_rqReadonly || AppSettings.AllowConcurrentRequestsPerSession)
                     {
                         GetItemResult result = await _store.GetItemAsync(_rqContext, _rqId, GetCancellationToken());
                         if (result != null)
@@ -701,7 +705,7 @@ private async Task GetSessionStateItemAsync()
                             QueueRef();
                             isQueued = true;
                         }
-                        // TODO: The retry timeout should be configurable.
+                        
                         if (lockAge >= _rqExecutionTimeout)
                         {
                             /* Release the lock on the item, which is held by another thread*/
@@ -786,15 +790,7 @@ private static void LookUpRegForPollInterval()
                 }
             }
         }
-
-        // Called by OnReleaseState to get the session id.
-        private string ReleaseStateGetSessionId()
-        {
-            Debug.Assert(_rqId != null, "_rqId != null");
-            return _rqId;
-        }
-
-
+        
         // Release session state
         private Task ReleaseStateAsync(HttpApplication application)
         {
@@ -849,15 +845,15 @@ private async Task ReleaseStateAsyncImpl(HttpApplication application)
                     // we need to explicitly call Session_End.
                     if (_supportSessionExpiry)
                     {
-                        _onEndTarget.RaiseSessionOnEnd(ReleaseStateGetSessionId(), _rqItem);
+                        _onEndTarget.RaiseSessionOnEnd(_rqId, _rqItem);
                     }
                 }
                 else
                 {
                     Debug.Assert(_rqItem != null, "_rqItem cannot null if it's not a new session");
 
                     // Remove it from the store because the session is abandoned.
-                    await _store.RemoveItemAsync(_rqContext, ReleaseStateGetSessionId(), _rqLockId, _rqItem, GetCancellationToken());
+                    await _store.RemoveItemAsync(_rqContext, _rqId, _rqLockId, _rqItem, GetCancellationToken());
                 }
             }
             else if (!_rqReadonly ||
@@ -882,8 +878,7 @@ private async Task ReleaseStateAsyncImpl(HttpApplication application)
                     }
 
                     setItemCalled = true;
-                    await
-                        _store.SetAndReleaseItemExclusiveAsync(_rqContext, ReleaseStateGetSessionId(), _rqItem,
+                    await _store.SetAndReleaseItemExclusiveAsync(_rqContext, _rqId, _rqItem,
                             _rqLockId, _rqSessionStateNotFound, GetCancellationToken());
                 }
                 else
@@ -892,8 +887,7 @@ private async Task ReleaseStateAsyncImpl(HttpApplication application)
                     if (!_rqSessionStateNotFound)
                     {
                         Debug.Assert(_rqItem != null, "_rqItem cannot null if it's not a new session");
-                        await
-                            _store.ReleaseItemExclusiveAsync(_rqContext, ReleaseStateGetSessionId(), _rqLockId,
+                        await _store.ReleaseItemExclusiveAsync(_rqContext, _rqId, _rqLockId,
                                 GetCancellationToken());
                     }
                 }