Kicinski: netdev in 2024

Kernel networking maintainer Jakub Kicinski reviews progress inthe networking subsystem in 2024.

Work on relieving the rtnl_lock pressure has continued throughoutthe year. The rtnl_lock is often mentioned as one of the biggestglobal locks in the kernel, as it protects all of the networkconfiguration and state. The efforts can be divided into two broadcategories - converting read operations to rely on RCU protectionor other fine grained locking (v6.9, v6.10), and splitting the lockinto per-network namespace locks (preparations for which started inv6.13).