huahaofeng
/
aspnetcore
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

HTTP2: Write data and trailers under one lock (#24822)

This commit is contained in:
James Newton-King 2020-08-18 18:20:04 +12:00 committed by GitHub
parent c92eaa28f4
commit 28dc9bffab
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 51 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
src/Servers/Kestrel/Core/src/Internal/Http2/Http2FrameWriter.cs
View File

@ -198,7 +198,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
}
}
public ValueTask<FlushResult> WriteResponseTrailers(int streamId, HttpResponseTrailers headers)
public ValueTask<FlushResult> WriteResponseTrailersAsync(int streamId, HttpResponseTrailers headers)
{
lock (_writeLock)
{
@ -256,6 +256,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
public ValueTask<FlushResult> WriteDataAsync(int streamId, StreamOutputFlowControl flowControl, in ReadOnlySequence<byte> data, bool endStream, bool firstWrite, bool forceFlush)
{
// Logic in this method is replicated in WriteDataAndTrailersAsync.
// Changes here may need to be mirrored in WriteDataAndTrailersAsync.
// The Length property of a ReadOnlySequence can be expensive, so we cache the value.
var dataLength = data.Length;
@ -286,6 +289,43 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
}
}
public ValueTask<FlushResult> WriteDataAndTrailersAsync(int streamId, StreamOutputFlowControl flowControl, in ReadOnlySequence<byte> data, bool firstWrite, HttpResponseTrailers headers)
{
// This method combines WriteDataAsync and WriteResponseTrailers.
// Changes here may need to be mirrored in WriteDataAsync.
// The Length property of a ReadOnlySequence can be expensive, so we cache the value.
var dataLength = data.Length;
lock (_writeLock)
{
if (_completed || flowControl.IsAborted)
{
return default;
}
// Zero-length data frames are allowed to be sent immediately even if there is no space available in the flow control window.
// https://httpwg.org/specs/rfc7540.html#rfc.section.6.9.1
if (dataLength != 0 && dataLength > flowControl.Available)
{
return WriteDataAndTrailersAsyncCore(this, streamId, flowControl, data, dataLength, firstWrite, headers);
}
// This cast is safe since if dataLength would overflow an int, it's guaranteed to be greater than the available flow control window.
flowControl.Advance((int)dataLength);
WriteDataUnsynchronized(streamId, data, dataLength, endStream: false);
return WriteResponseTrailersAsync(streamId, headers);
}
static async ValueTask<FlushResult> WriteDataAndTrailersAsyncCore(Http2FrameWriter writer, int streamId, StreamOutputFlowControl flowControl, ReadOnlySequence<byte> data, long dataLength, bool firstWrite, HttpResponseTrailers headers)
{
await writer.WriteDataAsync(streamId, flowControl, data, dataLength, endStream: false, firstWrite);
return await writer.WriteResponseTrailersAsync(streamId, headers);
}
}
/* Padding is not implemented
+---------------+
|Pad Length? (8)|

17
src/Servers/Kestrel/Core/src/Internal/Http2/Http2OutputProducer.cs
View File

@ -423,16 +423,19 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2
{
// Output is ending and there are trailers to write
// Write any remaining content then write trailers
if (readResult.Buffer.Length > 0)
{
// Only flush if required (i.e. content length exceeds flow control availability)
// Writing remaining content without flushing allows content and trailers to be sent in the same packet
await _frameWriter.WriteDataAsync(StreamId, _flowControl, readResult.Buffer, endStream: false, firstWrite, forceFlush: false);
}
_stream.ResponseTrailers.SetReadOnly();
_stream.DecrementActiveClientStreamCount();
flushResult = await _frameWriter.WriteResponseTrailers(StreamId, _stream.ResponseTrailers);
if (readResult.Buffer.Length > 0)
{
// It is faster to write data and trailers together. Locking once reduces lock contention.
flushResult = await _frameWriter.WriteDataAndTrailersAsync(StreamId, _flowControl, readResult.Buffer, firstWrite, _stream.ResponseTrailers);
}
else
{
flushResult = await _frameWriter.WriteResponseTrailersAsync(StreamId, _stream.ResponseTrailers);
}
}
else if (readResult.IsCompleted && _streamEnded)
{