> Rather than starting _de novo_, have you looked closely at how
> FreeBSD-5 has evolved their TCP stack and the underlying network code
> to support fine-grained locking?

i looked it.  not very closely though.

> That said: in the specific case of mbufs, I beleive FreeBSD 5.x uses a
> replacement for the traditional mbuf/mbuf-cluster allocation, with
> per-CPU caches which solve two well-known problems: contention over
> allocation locks, and ping-ponging the underlying-end memory objects
> between CPUs. For more details, see the BSDCon 2004 paper:
> http://www.unixdaemons.com/~bmilekic/netbuf_bmilekic.pdf.
> 
> I have no idea whether we want to follow the directions in that paper
> (either mbuf-level API or underlying implemntation); but we should at
> least think about the quantitative data.

not relevant to my patch.

YAMAMOTO Takashi