Some things to expect in 2025
The extensible scheduling class (sched-ext) will be a game changer. Already we have seen, in 2024, how the ability to load a CPU scheduler from user space as a set of BPF programs has unleashed a great deal of creativity; that was before sched-ext was part of a released kernel. In 2025, this feature will start showing up in more distributions, and more people will be able to play with it. The result will be a flood of new scheduling ideas, each of which can be quickly tested (and improved) on real systems. Some of those ideas will result in specialty schedulers included with focused distributions (systems for gaming, for example); others, hopefully, will eventually find their way into the kernel's EEVDF scheduler.
Code written in Rust will land in the kernel at an increasing rate over the course of the year as a result of the increased availability of abstractions and greater familiarity with the language in the kernel community. The Rust code that has been merged so far is mostly infrastructure and proofs of concept; in 2025, we'll see Rust code that end users will run — but they may never notice. The number of unstable language features needed by the kernel will drop significantly as those features are stabilized by the Rust community.
Another XZ-like backdoor attempt will come to light. Existing code bases have been scoured for attacks similar to those used against XZ; little has been found, but that does not mean that there are not other ongoing efforts, using different techniques, out there. The potential payoff for a government agency or other suitably well-funded organization is simply too high for all of them to ignore; somebody is surely trying something.
