diff options
Diffstat (limited to 'MediaBrowser.Controller/LibraryTaskScheduler/LimitedConcurrencyLibraryScheduler.cs')
| -rw-r--r-- | MediaBrowser.Controller/LibraryTaskScheduler/LimitedConcurrencyLibraryScheduler.cs | 152 |
1 files changed, 122 insertions, 30 deletions
diff --git a/MediaBrowser.Controller/LibraryTaskScheduler/LimitedConcurrencyLibraryScheduler.cs b/MediaBrowser.Controller/LibraryTaskScheduler/LimitedConcurrencyLibraryScheduler.cs index 6da398129a..be75117b6f 100644 --- a/MediaBrowser.Controller/LibraryTaskScheduler/LimitedConcurrencyLibraryScheduler.cs +++ b/MediaBrowser.Controller/LibraryTaskScheduler/LimitedConcurrencyLibraryScheduler.cs @@ -17,7 +17,8 @@ namespace MediaBrowser.Controller.LibraryTaskScheduler; /// </summary> public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibraryScheduler, IAsyncDisposable { - private const int CleanupGracePeriod = 60; + private static readonly TimeSpan _cleanupGracePeriod = TimeSpan.FromSeconds(60); + private readonly IHostApplicationLifetime _hostApplicationLifetime; private readonly ILogger<LimitedConcurrencyLibraryScheduler> _logger; private readonly IServerConfigurationManager _serverConfigurationManager; @@ -31,6 +32,8 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr private readonly Lock _taskLock = new(); private readonly Channel<TaskQueueItem> _tasks = Channel.CreateUnbounded<TaskQueueItem>(); + private readonly CancellationTokenSource _disposeTokenSource = new(); + private readonly TimeSpan _gracePeriod; private volatile int _workCounter; private Task? _cleanupTask; @@ -46,10 +49,34 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr IHostApplicationLifetime hostApplicationLifetime, ILogger<LimitedConcurrencyLibraryScheduler> logger, IServerConfigurationManager serverConfigurationManager) + : this(hostApplicationLifetime, logger, serverConfigurationManager, _cleanupGracePeriod) + { + } + + internal LimitedConcurrencyLibraryScheduler( + IHostApplicationLifetime hostApplicationLifetime, + ILogger<LimitedConcurrencyLibraryScheduler> logger, + IServerConfigurationManager serverConfigurationManager, + TimeSpan gracePeriod) { _hostApplicationLifetime = hostApplicationLifetime; _logger = logger; _serverConfigurationManager = serverConfigurationManager; + _gracePeriod = gracePeriod; + } + + /// <summary> + /// Gets the number of runners the scheduler currently keeps alive. + /// </summary> + internal int ActiveRunnerCount + { + get + { + lock (_taskLock) + { + return _taskRunners.Count; + } + } } private void ScheduleTaskCleanup() @@ -68,31 +95,65 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr async Task RunCleanupTask() { - _logger.LogDebug("Schedule cleanup task in {CleanupGracePerioid} sec.", CleanupGracePeriod); - await Task.Delay(TimeSpan.FromSeconds(CleanupGracePeriod)).ConfigureAwait(false); - if (_disposed) + while (true) { - _logger.LogDebug("Abort cleaning up, already disposed."); - return; - } + _logger.LogDebug("Schedule cleanup task in {CleanupGracePeriod}.", _gracePeriod); + try + { + await Task.Delay(_gracePeriod, _disposeTokenSource.Token).ConfigureAwait(false); + } + catch (OperationCanceledException) + { + _logger.LogDebug("Abort cleaning up, already disposed."); + return; + } - lock (_taskLock) - { - if (_tasks.Reader.Count > 0 || _workCounter > 0) + if (_disposed) { - _logger.LogDebug("Delay cleanup task, operations still running."); - // tasks are still there so its still in use. Reschedule cleanup task. - // we cannot just exit here and rely on the other invoker because there is a considerable timeframe where it could have already ended. - _cleanupTask = RunCleanupTask(); + _logger.LogDebug("Abort cleaning up, already disposed."); return; } + + CancellationTokenSource[] runners; + lock (_taskLock) + { + if (_tasks.Reader.Count > 0 || _workCounter > 0) + { + _logger.LogDebug("Delay cleanup task, operations still running."); + // tasks are still there so its still in use. Wait another grace period. + // we cannot just exit here and rely on the other invoker because there is a considerable timeframe where it could have already ended. + continue; + } + + runners = [.. _taskRunners.Keys]; + + // Retire the runners before they are told to stop: an operation starting while + // they wind down must spawn its own instead of counting these towards the fanout. + _taskRunners.Clear(); + + // Hand the next operation the ability to schedule a cleanup again. Without this + // the very first cleanup would be the only one that ever runs. + _cleanupTask = null; + } + + _logger.LogDebug("Cleanup runners."); + await StopRunners(runners).ConfigureAwait(false); + return; } + } + } - _logger.LogDebug("Cleanup runners."); - foreach (var item in _taskRunners.ToArray()) + private static async Task StopRunners(CancellationTokenSource[] runners) + { + foreach (var runner in runners) + { + try { - await item.Key.CancelAsync().ConfigureAwait(false); - _taskRunners.Remove(item.Key); + await runner.CancelAsync().ConfigureAwait(false); + } + catch (ObjectDisposedException) + { + // The runner already stopped on its own and disposed its stop source. } } } @@ -127,12 +188,17 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr { var stopToken = new CancellationTokenSource(); var combinedSource = CancellationTokenSource.CreateLinkedTokenSource(stopToken.Token, _hostApplicationLifetime.ApplicationStopping); + + // Keyed on its own stop source, because cancelling that is what reaches the linked + // source the runner waits on. Cancellation does not travel the other way. + // Started without the runner's own token: a task cancelled before it is scheduled + // never runs its body, so it would never take itself out of _taskRunners again. _taskRunners.Add( - combinedSource, + stopToken, Task.Factory.StartNew( ItemWorker, - (combinedSource, stopToken), - combinedSource.Token, + (stopToken, combinedSource), + CancellationToken.None, TaskCreationOptions.PreferFairness, TaskScheduler.Default)); } @@ -145,7 +211,7 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr _deadlockDetector.Value = stopToken.TaskStop; try { - while (!stopToken.GlobalStop.Token.IsCancellationRequested) + while (!stopToken.GlobalStop.IsCancellationRequested) { var item = await _tasks.Reader.ReadAsync(stopToken.GlobalStop.Token).ConfigureAwait(false); try @@ -162,15 +228,24 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr } } } - catch (OperationCanceledException) when (stopToken.TaskStop.IsCancellationRequested) + catch (OperationCanceledException) when (stopToken.GlobalStop.IsCancellationRequested) { // thats how you do it, interupt the waiter thread. There is nothing to do here when it was on purpose. } + catch (ChannelClosedException) + { + // the scheduler was disposed and will not hand out any more work. + } finally { _logger.LogDebug("Cleanup Runner'."); _deadlockDetector.Value = default!; - _taskRunners.Remove(stopToken.TaskStop); + + lock (_taskLock) + { + _taskRunners.Remove(stopToken.TaskStop); + } + stopToken.GlobalStop.Dispose(); stopToken.TaskStop.Dispose(); } @@ -195,7 +270,7 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr finally { item.Progress.Report(100); - item.Done.SetResult(); + item.Done.TrySetResult(); } } @@ -285,16 +360,33 @@ public sealed class LimitedConcurrencyLibraryScheduler : ILimitedConcurrencyLibr _disposed = true; _tasks.Writer.Complete(); - foreach (var item in _taskRunners) + + // Nobody is left to run these, so release whoever is waiting on them. + while (_tasks.Reader.TryRead(out var item)) { - await item.Key.CancelAsync().ConfigureAwait(false); + item.Done.TrySetResult(); } - if (_cleanupTask is not null) + CancellationTokenSource[] runners; + Task? cleanupTask; + lock (_taskLock) { - await _cleanupTask.ConfigureAwait(false); - _cleanupTask?.Dispose(); + runners = [.. _taskRunners.Keys]; + _taskRunners.Clear(); + cleanupTask = _cleanupTask; } + + await StopRunners(runners).ConfigureAwait(false); + + // Cuts the grace period short instead of holding up shutdown for the rest of it. + await _disposeTokenSource.CancelAsync().ConfigureAwait(false); + + if (cleanupTask is not null) + { + await cleanupTask.ConfigureAwait(false); + } + + _disposeTokenSource.Dispose(); } private class TaskQueueItem |