Post Syndicated from corbet original https://lwn.net/Articles/1081871/

Processes that use io_uring
tend to keep a lot of balls in the air; being able to have many operations
underway at any given time is part of the point of that API in the first
place. The io_uring subsystem must, as a result, keep track of a lot of
tasks that have to be performed at the right time. In current kernels,
io_uring uses a standard kernel linked-list primitive to track those work
items. As of the 7.2 kernel release, though, io_uring will, instead, use a
new lockless, multi-producer, single-consumer (MPSC) queue, resulting in
some notable performance gains. Lockless algorithms tend to be tricky, but
the one used here is relatively approachable and shows how these algorithms
can work.