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.
---
