Concurrent page-fault handling with per-VMA locks

The reason Emacs uses so many VMAs is the new Emacs Lisp Native Compilation feature introduced in version 28.1. Each Emacs Lisp file (.el) can be compiled into a byte-code file (.elc), which in turn can be compiled into a .eln file, which is a standard shared object file with a different file name suffix. (On Windows the files are DLLs.)

Loading a lot of Emacs Lisp libraries can result in a zillion shared objects being loaded, each with their own VMAs.