LWN articles on Linux kernel

posted by Roy Schestowitz on Oct 10, 2024

• LWN ☛ The rest of the 6.12 merge window

  Linus Torvalds released 6.12-rc1 and closed the 6.12 merge window on September 29; at that point, 11,260 non-merge change sets had been pulled into the mainline for the 6.12 release. That is the lowest number of merge-window changes since 5.17-rc1 in January 2022, which brought in 11,068 changesets. Nonetheless, 6.12 brings a number of interesting changes, many of which were included in the roughly 4,500 changes merged since the summary of the first half of the 6.12 merge window was written.

• LWN ☛ Sched_ext at LPC 2024

  The extensible scheduler class (sched_ext) enables the implementation of CPU schedulers as a set of BPF programs loaded from user space; it first hit the mailing lists in late 2022. Sched_ext has engendered its share of controversy since, but is currently slated to be part of the 6.12 kernel release. At the 2024 Linux Plumbers Conference, the growing sched_ext community held one of its first public gatherings; sched_ext would appear to have launched a new burst of creativity in scheduler design.

• LWN ☛ Getting PCI driver abstractions upstream

  Danilo Krummrich gave a talk at Kangrejos 2024 focusing on the question of how the Rust-for-Linux project could improve at getting device and driver abstractions upstream. As a case study, he used some of his recent work that attempts to make it possible to write a PCI driver entirely in Rust. There wasn't time to go into as much detail as he would have liked, but he did demonstrate that it is possible to interface with the kernel's module loader in a way that is much harder to screw up than the current standard approach in C.

  To give context to the discussion, he started by explaining that his goal was to make development of Nova (the new NVIDIA driver he has been working on) go smoothly. He opined that Nova would probably be the first "more complex" thing to go upstream. Luckily, other in-progress efforts to write kernel components in Rust need some of the same abstractions as Nova, including rvkms, rnvme, Apple AGX, and rcpufreq-dt. Ultimately, he would like to provide driver infrastructure that integrates with the kernel, but that takes advantage of Rust's capabilities where possible.

• LWN ☛ BTF, Rust, and the kernel toolchain

  BPF Type Format (BTF), BPF's debugging information format, has undergone rapid evolution to match the evolving needs of BPF programs. José Marchesi spoke at Kangrejos about some of that work — and how it could impact Rust, specifically. He discussed debug information, kernel-specific relocations, and the planned changes to kernel stack unwinding. Each of these will require some amount of work to fully support in Rust, but preliminary signs look promising.