Worked on stabilizing EdenFS for the facebook/sapling repository, focusing on resolving a concurrency deadlock affecting macOS file I/O during large directory walks. Addressed the issue by moving PID detail resolution off NFS dispatch threads and introducing a background resolver, leveraging Rust’s concurrency primitives such as Arc, AtomicU64, and OnceLock to maintain shared state safely. This approach prevented system hangs and preserved expected logging behavior, improving developer workflows across tools like Watchman and VS Code. Established telemetry-driven metrics to measure the impact of the fix, and documented the changes through peer review, emphasizing performance optimization and robust system programming practices.