[$] Transparent huge pages for filesystems

One thing that is known about using transparent huge pages (THPs) forfilesystems is that it is a hard problem to solve, but is there a solid firststep that could be taken toward that goal? That is the question Song Liu asked toopen his combined filesystem and memory-management session atthe 2019 Linux Storage, Filesystem, and Memory-Management Summit (LSFMM).His employer, Facebook, has a solid use case for using THPs on files inthe page cache, which may provide a starting point.