July 28, 2026
Queue the chaos
Lockless MPSC FIFO queues for io_uring
Linux just ditched a clunky old line system, and the comments are cheering and arguing
TLDR: Linux 7.2 changes a behind-the-scenes line system in io_uring so busy programs can handle lots of jobs more smoothly and fairly. Commenters are split between cheering the speedup and joking that the new lock-free code is brilliant, terrifying, or both.
Deep in the world of Linux plumbing, one of those tiny changes nobody outside developer circles usually notices has somehow turned into catnip for comment-section drama. The news: the system behind io_uring — a tool programs use to juggle lots of file and network jobs at once — is replacing its old task queue in kernel 7.2 with a new design that keeps jobs in order and cuts wasted effort. Translation for normal humans: the operating system found a faster, less awkward way to keep track of a pile of to-dos.
And yes, the community absolutely had thoughts. The loudest camp was basically yelling, "finally!" They mocked the old setup as a weird backward pile that had to be flipped around before use, with several commenters joking that Linux had been "making a sandwich by cooking it upside down." Fans of the patch loved that it promises fairness, less fighting over shared data, and solid speed gains.
But this is tech, so celebration instantly became debate. Skeptics rolled in with the classic hot take: "faster on paper, scarier in real life." Lock-free code has a reputation for being nightmare fuel, and the comments were full of equal parts admiration and terror. Some praised Jens Axboe for pulling off a clever cleanup; others basically said, "Congrats, now nobody but five people on Earth can debug it." The joke mood? Heavy. Think "no locks, no gods, no peace" energy, plus the usual worship of tiny performance wins as if someone had just discovered fire again.
Key Points
- •io_uring in Linux kernel 7.2 is switching from `llist`-based task queues to a lockless MPSC queue.
- •The older `llist` approach behaved like a stack for producer-consumer use, forcing io_uring to reverse queues to restore FIFO processing order.
- •Partial processing of reversed `llist` queues required maintaining a second list for reversed but unprocessed work items.
- •The new queue implementation was posted by Jens Axboe and is based on an algorithm credited to Dmitry Vyukov.
- •The MPSC design uses a tail pointer and a stub sentinel node, allowing multiple producers to append without locks while reducing contention and avoiding queue reversal.