Too small mbuf clusters

[Martin Husemann <martin%duskware.de@localhost>]

Hey folks,

would bad things happen if I would create an mbuf cluster < MINCLSIZE?

It seems that FreeBSD uses clusters in situations where we would create
a two mbuf chain, and I have a case where having continous memory makes
things a lot easier (and the packet in question is > 1 MHLEN on
all architectures with MSIZE=256).

Or (with all the pools we now have in place) would it make sense to
lower MINCLSIZE to MHLEN+1 ?

We now have (sys/sys/mbuf.h line 327):

#define MINCLSIZE       (MHLEN+MLEN+1)  /* smallest amount to put in cluster */

that is: create a cluster whenever we exceed two mbufs (first with header,
second plain).

Martin