Skip to content

Use a single lock for writing to ConcurrentPipeWriter #12285

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 6 commits into from
Jul 17, 2019
Merged

Use a single lock for writing to ConcurrentPipeWriter #12285

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
f2f2e25
reduce locks
jkotalik Jul 17, 2019
d49cbec
Remove locks!
jkotalik Jul 17, 2019
7ed4ed2
same lock in Http2FrameWriter
jkotalik Jul 17, 2019
c3fdb6a
Pass lock in
jkotalik Jul 17, 2019
020b071
fix lock
jkotalik Jul 17, 2019
d9c76a9
Update src/Servers/Kestrel/Core/src/Internal/Infrastructure/PipeWrite…
jkotalik Jul 17, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion src/Servers/Kestrel/Core/src/Internal/Http/Http1OutputProducer.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,7 @@ public Http1OutputProducer(
MemoryPool<byte> memoryPool)
{
// Allow appending more data to the PipeWriter when a flush is pending.
_pipeWriter = new ConcurrentPipeWriter(pipeWriter, memoryPool);
_pipeWriter = new ConcurrentPipeWriter(pipeWriter, memoryPool, _contextLock);
_connectionId = connectionId;
_connectionContext = connectionContext;
_log = log;
Expand Down
2 changes: 1 addition & 1 deletion src/Servers/Kestrel/Core/src/Internal/Http2/Http2FrameWriter.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ public Http2FrameWriter(
IKestrelTrace log)
{
// Allow appending more data to the PipeWriter when a flush is pending.
_outputWriter = new ConcurrentPipeWriter(outputPipeWriter, memoryPool);
_outputWriter = new ConcurrentPipeWriter(outputPipeWriter, memoryPool, _writeLock);
_connectionContext = connectionContext;
_http2Connection = http2Connection;
_connectionOutputFlowControl = connectionOutputFlowControl;
Expand Down
2 changes: 1 addition & 1 deletion src/Servers/Kestrel/Core/src/Internal/Http2/Http2OutputProducer.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ public Http2OutputProducer(

var pipe = CreateDataPipe(pool);

_pipeWriter = new ConcurrentPipeWriter(pipe.Writer, pool);
_pipeWriter = new ConcurrentPipeWriter(pipe.Writer, pool, _dataWriterLock);
_pipeReader = pipe.Reader;

// No need to pass in timeoutControl here, since no minDataRates are passed to the TimingPipeFlusher.
Expand Down
145 changes: 64 additions & 81 deletions ...ervers/Kestrel/Core/src/Internal/Infrastructure/PipeWriterHelpers/ConcurrentPipeWriter.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ internal sealed class ConcurrentPipeWriter : PipeWriter

private static readonly Exception _successfullyCompletedSentinel = new Exception();

private readonly object _sync = new object();
private readonly object _sync;
private readonly PipeWriter _innerPipeWriter;
private readonly MemoryPool<byte> _pool;
private readonly BufferSegmentStack _bufferSegmentPool = new BufferSegmentStack(InitialSegmentPoolSize);
Expand Down Expand Up @@ -51,97 +51,86 @@ internal sealed class ConcurrentPipeWriter : PipeWriter
private bool _aborted;
private Exception _completeException;

public ConcurrentPipeWriter(PipeWriter innerPipeWriter, MemoryPool<byte> pool)
public ConcurrentPipeWriter(PipeWriter innerPipeWriter, MemoryPool<byte> pool, object sync)
{
_innerPipeWriter = innerPipeWriter;
_pool = pool;
_sync = sync;
}

public override Memory<byte> GetMemory(int sizeHint = 0)
{
lock (_sync)
if (_currentFlushTcs == null && _head == null)
{
if (_currentFlushTcs == null && _head == null)
{
return _innerPipeWriter.GetMemory(sizeHint);
}

AllocateMemoryUnsynchronized(sizeHint);
return _tailMemory;
return _innerPipeWriter.GetMemory(sizeHint);
}

AllocateMemoryUnsynchronized(sizeHint);
return _tailMemory;
}

public override Span<byte> GetSpan(int sizeHint = 0)
{
lock (_sync)
if (_currentFlushTcs == null && _head == null)
{
if (_currentFlushTcs == null && _head == null)
{
return _innerPipeWriter.GetSpan(sizeHint);
}

AllocateMemoryUnsynchronized(sizeHint);
return _tailMemory.Span;
return _innerPipeWriter.GetSpan(sizeHint);
}

AllocateMemoryUnsynchronized(sizeHint);
return _tailMemory.Span;
}

public override void Advance(int bytes)
{
lock (_sync)
if (_currentFlushTcs == null && _head == null)
{
if (_currentFlushTcs == null && _head == null)
{
_innerPipeWriter.Advance(bytes);
return;
}

if ((uint)bytes > (uint)_tailMemory.Length)
{
ThrowArgumentOutOfRangeException(nameof(bytes));
}
_innerPipeWriter.Advance(bytes);
return;
}

_tailBytesBuffered += bytes;
_bytesBuffered += bytes;
_tailMemory = _tailMemory.Slice(bytes);
_bufferedWritePending = false;
if ((uint)bytes > (uint)_tailMemory.Length)
{
ThrowArgumentOutOfRangeException(nameof(bytes));
}

_tailBytesBuffered += bytes;
_bytesBuffered += bytes;
_tailMemory = _tailMemory.Slice(bytes);
_bufferedWritePending = false;
}

public override ValueTask<FlushResult> FlushAsync(CancellationToken cancellationToken = default)
{
lock (_sync)
if (_currentFlushTcs != null)
{
if (_currentFlushTcs != null)
{
return new ValueTask<FlushResult>(_currentFlushTcs.Task);
}
return new ValueTask<FlushResult>(_currentFlushTcs.Task);
}

if (_bytesBuffered > 0)
{
CopyAndReturnSegmentsUnsynchronized();
}
if (_bytesBuffered > 0)
{
CopyAndReturnSegmentsUnsynchronized();
}

var flushTask = _innerPipeWriter.FlushAsync(cancellationToken);
var flushTask = _innerPipeWriter.FlushAsync(cancellationToken);

if (flushTask.IsCompletedSuccessfully)
if (flushTask.IsCompletedSuccessfully)
{
if (_currentFlushTcs != null)
{
if (_currentFlushTcs != null)
{
CompleteFlushUnsynchronized(flushTask.GetAwaiter().GetResult(), null);
}

return flushTask;
CompleteFlushUnsynchronized(flushTask.GetAwaiter().GetResult(), null);
}

// Use a TCS instead of something resettable so it can be awaited by multiple awaiters.
_currentFlushTcs = new TaskCompletionSource<FlushResult>(TaskCreationOptions.RunContinuationsAsynchronously);
var result = new ValueTask<FlushResult>(_currentFlushTcs.Task);

// FlushAsyncAwaited clears the TCS prior to completing. Make sure to construct the ValueTask
// from the TCS before calling FlushAsyncAwaited in case FlushAsyncAwaited completes inline.
_ = FlushAsyncAwaited(flushTask, cancellationToken);
return result;
return flushTask;
}

// Use a TCS instead of something resettable so it can be awaited by multiple awaiters.
_currentFlushTcs = new TaskCompletionSource<FlushResult>(TaskCreationOptions.RunContinuationsAsynchronously);
var result = new ValueTask<FlushResult>(_currentFlushTcs.Task);

// FlushAsyncAwaited clears the TCS prior to completing. Make sure to construct the ValueTask
// from the TCS before calling FlushAsyncAwaited in case FlushAsyncAwaited completes inline.
_ = FlushAsyncAwaited(flushTask, cancellationToken);
return result;
}

private async Task FlushAsyncAwaited(ValueTask<FlushResult> flushTask, CancellationToken cancellationToken)
Expand Down Expand Up @@ -199,40 +188,34 @@ public override void CancelPendingFlush()

public override void Complete(Exception exception = null)
{
lock (_sync)
{
// We store the complete exception or s sentinel exception instance in a field if a flush was ongoing.
// We call the inner Complete() method after the flush loop ended.
// We store the complete exception or s sentinel exception instance in a field if a flush was ongoing.
// We call the inner Complete() method after the flush loop ended.

// To simply ensure everything gets returned after the PipeWriter is left in some unknown state (say GetMemory() was
// called but not Advance(), or there's a flush pending), but you don't want to complete the inner pipe, just call Abort().
_completeException = exception ?? _successfullyCompletedSentinel;
// To simply ensure everything gets returned after the PipeWriter is left in some unknown state (say GetMemory() was
// called but not Advance(), or there's a flush pending), but you don't want to complete the inner pipe, just call Abort().
_completeException = exception ?? _successfullyCompletedSentinel;

if (_currentFlushTcs == null)
if (_currentFlushTcs == null)
{
if (_bytesBuffered > 0)
{
if (_bytesBuffered > 0)
{
CopyAndReturnSegmentsUnsynchronized();
}
CopyAndReturnSegmentsUnsynchronized();
}

CleanupSegmentsUnsynchronized();
CleanupSegmentsUnsynchronized();

_innerPipeWriter.Complete(exception);
}
_innerPipeWriter.Complete(exception);
}
}

public void Abort()
{
lock (_sync)
{
_aborted = true;
_aborted = true;

// If we're flushing, the cleanup will happen after the flush.
if (_currentFlushTcs == null)
{
CleanupSegmentsUnsynchronized();
}
// If we're flushing, the cleanup will happen after the flush.
if (_currentFlushTcs == null)
{
CleanupSegmentsUnsynchronized();
}
}

Expand Down
10 changes: 5 additions & 5 deletions src/Servers/Kestrel/Core/test/ConcurrentPipeWriterTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ public async Task PassthroughIfAllFlushesAreAwaited()
};

var mockPipeWriter = new MockPipeWriter(pipeWriterFlushTcsArray);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool, new object());

var memory = concurrentPipeWriter.GetMemory();
Assert.Equal(1, mockPipeWriter.GetMemoryCallCount);
Expand Down Expand Up @@ -72,7 +72,7 @@ public async Task QueuesIfFlushIsNotAwaited()
};

var mockPipeWriter = new MockPipeWriter(pipeWriterFlushTcsArray);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool, new object());

var memory = concurrentPipeWriter.GetMemory();
Assert.Equal(1, mockPipeWriter.GetMemoryCallCount);
Expand Down Expand Up @@ -152,7 +152,7 @@ public async Task KeepsQueueIfInnerFlushFinishesBetweenGetMemoryAndAdvance()
};

var mockPipeWriter = new MockPipeWriter(pipeWriterFlushTcsArray);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool, new object());

var memory = concurrentPipeWriter.GetMemory();
Assert.Equal(1, mockPipeWriter.GetMemoryCallCount);
Expand Down Expand Up @@ -218,7 +218,7 @@ public async Task CompleteFlushesQueuedBytes()
};

var mockPipeWriter = new MockPipeWriter(pipeWriterFlushTcsArray);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool, new object());

var memory = concurrentPipeWriter.GetMemory();
Assert.Equal(1, mockPipeWriter.GetMemoryCallCount);
Expand Down Expand Up @@ -273,7 +273,7 @@ public async Task CancelPendingFlushInterruptsFlushLoop()
};

var mockPipeWriter = new MockPipeWriter(pipeWriterFlushTcsArray);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool);
var concurrentPipeWriter = new ConcurrentPipeWriter(mockPipeWriter, diagnosticPool, new object());

var memory = concurrentPipeWriter.GetMemory();
Assert.Equal(1, mockPipeWriter.GetMemoryCallCount);
Expand Down