Clarification of vnode sysctls as numvnodes doesnt decrease (FBSD12.2)?

[Dewayne Geraghty]

I used procstat to tally the number of vnodes that are actually in use,
in my case its 925.  Now this is relatively idle (load <10%) unless its
building os or ports.  As we do build in jails, we have a large number
of vnodes.  From sysctl's

kern.maxvnodes=700000
vfs.wantfreevnodes=175000
vfs.numvnodes=700000
vfs.ncpurgeminvnodes=256

should vfs.numvnodes be read as 700,000 vnodes are available, or as the
memory has been allocated, or remain linked in some way to the file that
they were previously associated with(the latter seems crazy)?  In
previous versions of FreeBSD the vfs.numvnodes did decrease, somewhat.

If the vnodes are allocated, then during idle periods, would be a good
time to vacuum the vnodes, but how?

On FreeBSD 12.2-STABLE #0 r365645M
--------------------
Machines current state from tallying "procstat -f -a" and some relevant
sysctls:
Procstat file descriptor types
vn      sock    pipe    fifo    cryp    shmem   msg     posix   kque
Proc    term
925     302     342     99      0       3       0       0       20
0       15

Procstat vnode types
block   char    dir     fifo    slink   regfile sock    revdev  notvn
0       289     303     0       0       333     0       0       782


Correlate with
kern.openfiles=857
kern.ipc.numopensockets=264
Network connections via netstat -na: 160