- Use sbuf_new_for_sysctl() to reduce double-buffering on sysctl
output.
- Use much faster sbuf_cat() instead of sbuf_printf("%s").
Together it reduces `sysctl kstat.zfs.misc.dbufs` time from minutes
to seconds, making dbufstat almost usable.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes#15495
f13593619b