Dag-Erling Smørgrav des at des.no
Wed Mar 29 13:00:39 UTC 2006

"Conrad J. Sabatier" <conrads at cox.net> writes:
> Chris <chrcoluk at gmail.com> wrote:
> > so [kern.ipc.nmbclusters] has no affect, has this become a read only
> > tunable again only settable in loader.conf?
> To the best of my knowledge, this has *always* been a loader tunable,
> not configurable on-the-fly.

kern.ipc.nmbclusters is normally computed at boot time.  A compile-
time option to override it was introduced in 2.0-CURRENT.  At that
time, it was defined in param.c.  A read-only sysctl was introduced in
3.0-CURRENT.  It moved from param.c to uipc_mbuf.c in 4.0-CURRENT,
then to subr_mbuf.c when mballoc was introduced in 5.0-CURRENT; became
a tunable at some point after that; then moved again to kern_mbuf.c
when mballoc was replaced with mbuma in 6.0-CURRENT.  That is the
point where it became read-write, for no good reason that I can see;
setting it at runtime has no effect, because the size of the mbuf zone
is determined at boot time.  Perhaps Bosko (who wrote both mballoc and
mbuma, IIRC) knows.

Dag-Erling Smørgrav - des at des.no

More information about the freebsd-stable mailing list