Date: Wed, 9 Jul 1997 17:50:47 +1000 From: Bruce Evans <bde@zeta.org.au> To: hackers@FreeBSD.ORG, mango@communique.net Subject: Re: kern.maxvnodes and systat -v Message-ID: <199707090750.RAA17725@godzilla.zeta.org.au>
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>When running 2.1.7-RELEASE of freebsd, setting kern.maxvnodes=32000 on the kernel (sysctl -w ...) would increase the number of vnodes from the default. > >I could see this increase on the 'systat -v' window under buf on the bottom right column, under cow. > >The I upgraded to 2.2.2-RELEASE. > >Now systat -v show always '16415 buf' (ie, 16000). > >Is this a bug, or something I am reading wrong ? `buf' gives the number of Kbytes for buffers. It has nothing to do with kern.maxvnodes. The kern.maxvnodes sysctl is somewhat broken in all versions of FreeBSD. In all released versions, it changes a limit on the number of vnodes but not the size of the namecache hash table. This isn't much of a problem in practice. In some old unreleased versions, kern.maxvnodes was readonly. In -current, changing the variable behind kern.maxvnodes (desirevnodes) is a no-op (desiredvnodes no longer has anything to do with vnodes; it is only used to size the namecache hash table, and this table is initialized before the kern.maxvnode sysctl can be executed). Bruce
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