Always consume bytes for closed HTTP/2 streams. #3672
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Motivation: The current local flow controller does not guarantee that unconsumed bytes for a closed stream will be restored to the connection window. This may lead to degradation of the connection window over time. Modifications: Modified DefaultHttp2LocalFlowController to guarantee that any unconsumed bytes are returned to the connection window as soon as the stream is closed. We also immediately consume any bytes when receiving DATA for a closed stream. Result: Fixes netty#3668
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@Scottmitch can you take a look? |
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| @Override | ||
| public int unconsumedBytes(Http2Stream stream) { | ||
| return state(stream).unconsumedBytes(); | ||
| return isClosed(stream) ? 0 : state(stream).unconsumedBytes(); |
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Do we have to do this? If we are forcing the unconsumed bytes to 0 in the connection listener, is that good enough...or is this method used while the stream is being closed before the listener is notified?
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We probably don't need to do this in this PR. This was the result of some of my work for adding stream history, where closed streams would no longer have a FlowState property. Since we still need to apply flow control for closed streams, I didn't want these methods to require that the FlowState exist. WDYT ... revert this for now?
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@Scottmitch PTAL |
| // Update the number of active streams initiated by the endpoint. | ||
| stream.createdBy().numActiveStreams--; | ||
| } | ||
| notifyClosed(stream); |
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@Scottmitch this is somewhat unrelated, but I noticed that this seemed wrong. The previous logic would only let us close/remove if the stream had at one point become active. This change lifts this restriction.
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@nmittler - Good catch. I'm wondering if this should even be in this method. Would it make sense in DefaultStream.close() after state = CLOSED?
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@Scottmitch possibly. Although when onClosed() is called I would like it to be also removed from the active list. WDYT?
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Leave it per our discussion.
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@nmittler - Finished another round. Just 1 real question. |
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@Scottmitch I've replied to your question with a question :) |
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cherry-picked into master and 4.1 |
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Thanks @nmittler! |
Motivation:
The current local flow controller does not guarantee that unconsumed bytes for a closed stream will be restored to the connection window. This may lead to degradation of the connection window over time.
Modifications:
Modified DefaultHttp2LocalFlowController to guarantee that any unconsumed bytes are returned to the connection window as soon as the stream is closed. We also immediately consume any bytes when receiving DATA for a closed stream.
Result:
Fixes #3668