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ASF GitHub Bot commented on FLINK-7406: --------------------------------------- Github user NicoK commented on a diff in the pull request: https://github.com/apache/flink/pull/4509#discussion_r143225914 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/io/network/partition/consumer/RemoteInputChannel.java --- @@ -306,10 +311,27 @@ public void recycle(MemorySegment segment) { ExceptionUtils.rethrow(t); } } + + // Recycle the extra floating buffers in order not to stack up 2*initialCredit + // buffers once current backlog is 0 + if (senderBacklog.get() == 0 && availableBuffers.size() >= initialCredit) { --- End diff -- Actually, I guess, this should happen after adding the segment to `availableBuffers` and also not only when `senderBacklog.get() == 0`. The idiom you could follow is that after we integrated our exclusive buffer back, we should have a total of `buffersToMaintain = senderBacklog.get() + initialCredit` buffers. If there are more, we release `availableBuffers.size() - buffersToMaintain` _floating_ buffers accordingly. Since we only get one exclusive buffer back at a time, we only need to release at most one floating buffer here, as done by your code. > Implement Netty receiver incoming pipeline for credit-based > ----------------------------------------------------------- > > Key: FLINK-7406 > URL: https://issues.apache.org/jira/browse/FLINK-7406 > Project: Flink > Issue Type: Sub-task > Components: Network > Reporter: zhijiang > Assignee: zhijiang > Fix For: 1.4.0 > > > This is a part of work for credit-based network flow control. > Currently {{PartitionRequestClientHandler}} receives and reads > {{BufferResponse}} from producer. It will request buffer from {{BufferPool}} > for holding the message. If not got, the message is staged temporarily and > {{autoread}} for channel is set false. > For credit-based mode, {{PartitionRequestClientHandler}} can always get > buffer from {{RemoteInputChannel}} for reading messages from producer. > The related works are: > * Add the backlog of producer in {{BufferResponse}} message structure > * {{PartitionRequestClientHandler}} requests buffer from > {{RemoteInputChannel}} directly > * {{PartitionRequestClientHandler}} updates backlog for > {{RemoteInputChannel}}, and it may trigger requests of floating buffers from > {{BufferPool}} -- This message was sent by Atlassian JIRA (v6.4.14#64029)