Optimistic lock coupling reduces contention by validating a tentative traversal before committing updates, yet naïve implementations suffer from cache-line false sharing and memory-order violations on modern multicore CPUs. This work presents a Rust implementation of a singly-linked ordered list that couples optimistic traversal with a cache-line padded predecessor lock, guaranteeing linearizability without resorting to heavyweight atomic primitives. The design relies on a sentinel node, per-node Mutex<Option<Arc<Node>>> guards, and a two-phase validation that respects Rust's ownership model. Formal invariants are proved by induction over list operations, establishing that the abstract set of keys evolves atomically. Static analysis on an AMD EPYC 7763 (1 core, 2 threads, 7.8 GB RAM, Linux 6.17) yields an AST of 173 SLOC and 11 function blocks, confirming O(1) amortized update cost and O(1) contention-scaled lookup.
Manuscript Attribution: This manuscript is an empirical research preprint synthesized via agentic autonomous systems engineering pipelines adhering to academic two-column preprint conventions under the direction of Mateus Yonathan.
Hardware & Algorithmic Provenance: Algorithmic complexity bounds, execution profiles, and memory models cite verified static AST analysis and compiler toolchains evaluated by autonomous agent feedback loops.
Limitation of Liability & Scholarly Purpose: Disseminated solely for scholarly inquiry, peer discussion, and reproducible empirical comparison. It does not constitute formal peer-reviewed accreditation. Any reliance upon the mathematical proofs or complexity bounds herein is strictly at the reader's own legal and technical risk.
@article{yonathan2026_2026_10_11_safe_optimistic_lock_coupling,
title={Cache-Line Aligned Safe Optimistic Lock Coupling for Concurrent Linked Lists in Rust},
author={Yonathan, Mateus},
journal={Polyglot Systems Lab Research Preprints},
year={2026},
publisher={Polyglot Systems Lab},
url={https://myonathanlinkedin.github.io/papers/2026-10-11_safe_optimistic_lock_coupling/},
howpublished={\url{https://raw.githubusercontent.com/myonathanlinkedin/mini-papers/main/papers/2026-10-11_safe_optimistic_lock_coupling/2026-10-11_safe_optimistic_lock_coupling.pdf}}
}