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Date:      Wed, 29 Mar 2006 15:00:32 +0200
From:      des@des.no (Dag-Erling =?iso-8859-1?Q?Sm=F8rgrav?=)
To:        "Conrad J. Sabatier" <conrads@cox.net>
Cc:        Chris <chrcoluk@gmail.com>, freebsd-stable@freebsd.org, bmilekic@freebsd.org
Subject:   Re: nmbclusters
Message-ID:  <861wwlcsnj.fsf@xps.des.no>
In-Reply-To: <20060329030459.40be9cb2.conrads@cox.net> (Conrad J. Sabatier's message of "Wed, 29 Mar 2006 03:04:59 -0600")
References:  <3aaaa3a0603281134sd0d4e16x@mail.gmail.com> <20060329030459.40be9cb2.conrads@cox.net>

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"Conrad J. Sabatier" <conrads@cox.net> writes:
> Chris <chrcoluk@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.

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no



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