Claim exact idle generation before closing pooled channels - #2298
Merged
Conversation
![github-code-quality[bot]](https://avatars.githubusercontent.com/u/9919?s=60&v=4){kind=small}
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Motivation:
The idle cleaner read a channel's idle timestamp after deciding it had expired, so a lease and re-offer in that window closed a healthy keep-alive on a stale verdict (#2284). Hoisting that read alone leaves a second race: claim and validation stay two steps, so the cleaner can briefly own a generation it never evaluated while a racing poll drops the channel from the pool entirely.
Modification:
IdleState packs ownership, a transfer-in-progress flag and a generation counter into one atomic word, and the cleaner claims with a single CAS against the exact generation its verdict came from.
offer()now transfers ownership rather than stamping unconditionally, and flushPartitions claimsbefore closing so it never closes a channel another caller owns.Result:
Fixes #2284