[$] The kernel radar: folios, multi-generational LRU, and Rust

The kernel community is a busy place, so it is not even remotely possible
to write full-length articles about everything that is going on. Other
topics may be of interest, but not require a longer treatment. The
answer is a collection of short topics covering developments that are on
the radar; the selection this time around includes folios, the
multi-generational LRU, and Rust in the kernel.