Simple woking finalizer implementation.

dse · dse · commit 32af1f48be87 · 2017-08-29T01:54:57.000+04:00
diff --git a/src/runtime/pyreferencedecrementer.cs b/src/runtime/pyreferencedecrementer.cs
@@ -1,154 +1,61 @@
 using System;
 using System.Collections.Concurrent;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Python.Runtime
 {
     internal class PyReferenceDecrementer: IDisposable
     {
-        private readonly BlockingCollection<IntPtr> _asyncDecRefQueue = new BlockingCollection<IntPtr>();
         private readonly ConcurrentQueue<IntPtr> _decRefQueue = new ConcurrentQueue<IntPtr>();
-        private CancellationTokenSource _cts;
-        private CancellationToken _ct;
-        private Task _backgroundWorkerTask;
-        private bool _multipleThreadsAllowed;
 
-        public void ScheduleDecRef(IntPtr pyRef)
-        {
-            if (_multipleThreadsAllowed)
-            {
-                // ReSharper disable once MethodSupportsCancellation
-                _asyncDecRefQueue.Add(pyRef);
-            }
-            else
-            {
-                _decRefQueue.Enqueue(pyRef);
-            }
-        }
-
-        public void AllowMultipleThreads()
+        public void TryPerformScheduledDecrements()
         {
-            DecReferences();
-            _multipleThreadsAllowed = true;
-            InitDecRefThread();
+            //Trying to not affecting performance.
+            DecReferences(1000);
         }
 
-        public void DisableMultipleThreads()
+        public void ScheduleDecRef(IntPtr pyRef)
         {
-            ShutdownDecRefThread();
-            _multipleThreadsAllowed = false;
-        }
-
-        public void TryPerformScheduledDecrements()
-        {
-            if (!_multipleThreadsAllowed)
-            {
-                DecReferences();
-            }
+            _decRefQueue.Enqueue(pyRef);
         }
 
         public void FlushDecrementQueue()
         {
-            if (_multipleThreadsAllowed)
+            IntPtr gs = PythonEngine.AcquireLock();
+            try
             {
                 DecReferences();
             }
-            else
+            finally
             {
-                ShutdownDecRefThread();
-                InitDecRefThread();
+                PythonEngine.ReleaseLock(gs);
             }
         }
 
-        private void ShutdownDecRefThread()
-        {
-            _cts?.Cancel();
-            try
-            {
-                _backgroundWorkerTask.Wait();
-            }
-            catch
-            {
-                // Just stopping background thread.
-            }
-            _cts = null;
-            _ct = default(CancellationToken);
-
-            _backgroundWorkerTask = null;
-        }
-
-        private void InitDecRefThread()
-        {
-            _cts = new CancellationTokenSource();
-            _ct = _cts.Token;
-            _backgroundWorkerTask = Task.Factory.StartNew(WorkerThread, TaskCreationOptions.LongRunning);
-        }
-
-        private void DecReferences()
+        private void DecReferences(int? maxDecreases = null)
         {
             try
             {
+                int decreasedCount = 0;
                 IntPtr refToDecrease;
                 while (_decRefQueue.TryDequeue(out refToDecrease))
                 {
                     Runtime.XDecref(refToDecrease);
-                }
-            }
-            catch
-            {
-                // Do nothing.
-            }
-        }
-
-        private void WorkerThread()
-        {
-            try
-            {
-                while (true)
-                {
-                    IntPtr refToDecrease;
-
-                    refToDecrease = _asyncDecRefQueue.Take(_ct);
-
-                    try
+                    decreasedCount++;
+                    if (maxDecreases != null && decreasedCount > maxDecreases)
                     {
-                        IntPtr gs = PythonEngine.AcquireLock();
-                        try
-                        {
-                            do
-                            {
-                                Runtime.XDecref(refToDecrease);
-                            } while (_asyncDecRefQueue.TryTake(out refToDecrease));
-                        }
-                        finally
-                        {
-                            PythonEngine.ReleaseLock(gs);
-                        }
-                    }
-                    catch
-                    {
-                        // Nothing to do in this case.
+                        break;
                     }
                 }
             }
-            catch (OperationCanceledException)
+            catch
             {
-                // This is normal exit pass.
+                // Do nothing.
             }
         }
 
         public void Dispose()
         {
-            if (_multipleThreadsAllowed)
-            {
-                ShutdownDecRefThread();
-            }
-            else
-            {
-                DecReferences();
-            }
+            DecReferences();
         }
     }
-
 }
diff --git a/src/runtime/pythonengine.cs b/src/runtime/pythonengine.cs
@@ -1,4 +1,4 @@
-﻿using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -362,7 +362,6 @@ public static void ReleaseLock(IntPtr gs)
         /// </remarks>
         public static IntPtr BeginAllowThreads()
         {
-            CurrentRefDecrementer?.AllowMultipleThreads();
             return Runtime.PyEval_SaveThread();
         }
 
@@ -379,7 +378,6 @@ public static IntPtr BeginAllowThreads()
         /// </remarks>
         public static void EndAllowThreads(IntPtr ts)
         {
-            CurrentRefDecrementer?.DisableMultipleThreads();
             Runtime.PyEval_RestoreThread(ts);
         }
 

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-using System;`
	`1`	`+using System;`
`2`	`2`	`using System.Collections.Generic;`
`3`	`3`	`using System.IO;`
`4`	`4`	`using System.Linq;`
`@@ -362,7 +362,6 @@ public static void ReleaseLock(IntPtr gs)`
`362`	`362`	`/// </remarks>`
`363`	`363`	`public static IntPtr BeginAllowThreads()`
`364`	`364`	`{`
`365`		`- CurrentRefDecrementer?.AllowMultipleThreads();`
`366`	`365`	`return Runtime.PyEval_SaveThread();`
`367`	`366`	`}`
`368`	`367`
`@@ -379,7 +378,6 @@ public static IntPtr BeginAllowThreads()`
`379`	`378`	`/// </remarks>`
`380`	`379`	`public static void EndAllowThreads(IntPtr ts)`
`381`	`380`	`{`
`382`		`- CurrentRefDecrementer?.DisableMultipleThreads();`
`383`	`381`	`Runtime.PyEval_RestoreThread(ts);`
`384`	`382`	`}`
`385`	`383`