FreeBSD needs arc_adjust_zthr to run periodically for kstats to be
updated. A comment in the code suggests this may have been the
original intent in illumos as well:
c946d5a913/module/zfs/arc.c (L4697-L4700)
Create the thread with a 1 second timer.
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#10371
a9dcfac51c