Lock-Free Rust: How to Build a Rollercoaster While It's on Fire

Summary

“Every stitch in that flag was a commitment to thread safety without locks. std::atomic was the needle.” — Betsy Ross, Federalist Papers, Draft 29 (suppressed), 1782 Buckle your seatbelts, grab a helmet, and say goodbye to your loved ones because over the next few minutes, I am going to teach you more about lock-free data structures in Rust than any human being should reasonably know without a psychiatric evaluation. So sit down, shut up, and pretend you understand memory ordering, because thread safety is just a social construct and Ordering::Relaxed is just denial with extra steps. TL;DR We’re building LockFreeArray<T, N>, a fixed-size, lock-free array for storing heap-allocated values. It uses atomics and a freelist to insert and take values across threads without locks. You’ll learn: How AtomicPtr, AtomicUsize, and compare_exchange work. Why memory ordering matters (and how to screw it up). Where this kind of thing is useful (task slots, freelists, fixed-resource pools). And why it's generally a terrible idea unless you're very desperate or very clever. If you enjoy the read and want to see more content like this please check out our product yeet or our sandbox. Thank you. Lock-Free: The Decathlon of Danger Lock-free programming exists for the same reason people free solo climb cliffs without ropes: it’s fast, it’s elegant, and it absolutely will kill you if you do it wrong. Here at yeet, we have become masters in this. Specifically when it comes to building high-performance priority queues for real-time streaming of high volume events from BPF ring buffers. With Mutex<T> and RwLock<T>, you get warm, fuzzy guarantees — mutual exclusion, fairness, and the comfort of compile-time safety at the expense of speed. On the other hand, with lock-free, you get speed — but it's entirely on you to keep it safe. No waiting, no blocking, no help. It’s the difference between riding a rollercoaster and building one mid-air while it’s on fire — and you’re also the passenger. Co...