[$] High-granularity mappings for huge pages

The use of huge pages can make memory management more efficient in a numberof ways, but it can also impose costs in the form of internal fragmentation andI/O amplification. At the 2023 LinuxStorage, Filesystem, Memory-Management and BPF Summit, James Houghtonran a session on a scheme to get the best of both worlds: using huge pageswhile maintaining base-page mappings within them.