[$] Static keys for BPF
The kernel has a lot of code paths that are normally disabled: debugging print statements, tracepoints, etc. To support these efficiently, there is a common mechanism called static keys that provides a way to enable or disable a code path at run time, with effectively no overhead for disabled branches. BPF programs have not been able to take advantage of static keys so far, because they aren't compiled into the kernel. Now, it looks like BPF may be getting support for a similar mechanism — and the design could also provide one of the components needed to support jump tables, another missing feature. Anton Protopovov presented his plans to add static keys to BPF at the 2024 Linux Storage, Filesystem, Memory Management, and BPF Summit.