1996fanrui opened a new pull request, #29057:
URL: https://github.com/apache/flink/pull/29057
## What is the purpose of the change
In `LocalInputChannel`, `hasPendingPriorityEvent` is set lock-free in
`notifyPriorityEvent()` and cleared
lock-free in `pullPriorityFromSubpartitionView()` on a stale snapshot, which
is a latent lost-wakeup race.
It is currently safe because Flink runs no concurrent unaligned checkpoints,
so at most one priority barrier
is ever pending. This documents the race and why it is safe today, rather
than changing the logic.
## Brief change log
- [FLINK-40521] Add a comment in
`LocalInputChannel#pullPriorityFromSubpartitionView` describing the latent
lost-wakeup race and why it is currently safe.
## Verifying this change
This change is a trivial rework / code cleanup without any test coverage
(comment only, no behavior change).
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): no
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: no
- The serializers: no
- The runtime per-record code paths (performance sensitive): no
- Anything that affects deployment or recovery: no
- The S3 file system connector: no
## Documentation
- Does this pull request introduce a new feature? no
- If yes, how is the feature documented? not applicable
---
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