A module is for any mesh; the check reads the list of names at the root and the covered modules, and the kernel module's fixtures now say what they show.
With THP 'always' journald's mmapped journal files sit in 2 MiB folios, so each small
journal write dirties and writes back 2 MiB; on the control node that saturated the
root mirror holding the bus store and the store, and the controller lost its lease.
The module sets the mode from a per-machine setting (default always, the kernel's own,
so assigning it changes nothing until a machine sets madvise), verifies it took, rotates
the journal once so new files are mapped under the new mode, gives back what it found
when stopped, and serves kernel_huge_pages to measure file_thp per unit.