svn commit: r276750 - in head: share/man/man9 sys/contrib/ipfilter/netinet sys/dev/an sys/dev/bge sys/dev/ce sys/dev/cm sys/dev/cp sys/dev/cs sys/dev/ctau sys/dev/ed sys/dev/ex sys/dev/fe sys/dev/h...

[Robert N. M. Watson]

On 7 Jan 2015, at 20:48, Gleb Smirnoff <glebius at FreeBSD.org> wrote:

> R> > Shouldn't this come w/ a FreeBSD version bump for drivers to use?
> R> 
> R> Yes, probably.  Old drivers will continue to work fine in not checking the 
> R> return value (for now), but drivers seeing backporting will probably want a 
> R> __FreeBSD_version ifdef.  I'll do a commit to bump the version number today.
> R> 
> R> (In my local tree, M_EXT is renamed _M_EXT unless MBUF_PRIVATE is defined, 
> R> which really is quite a significant KPI change -- I'm not yet sure if I'm 
> R> going to push that into FreeBSD 11 or not.)
> 
> IMO, you should do the push :)
> 
> The faster we refactor the mbuf KPI, the better. Better do the surgery in
> one fast cut rather then do it in an endless serie of small but painful
> cuts.
> 
> Note that I'm still hoping of pushing projects/ifnet to 11, which is
> a much bigger KPI change from drivers.

The problem is really in structuring the changes so that they can be reviewed: they're very hard to test since they touch dozens (hundreds?) of drivers making them almost impossible to test effectively. Instead, I've been breaking them down into a series of less intrusive and easier to review chunks. The MLEN/MHLEN/MCLBYTES change should go into phabricator this evening, assuming a bunch of sanity tests run to completion successfully over the next few hours. These changes are really all just to facilitate underlying changes to the mbuf allocator by hiding more of the implementation details from consumers, so I want to get them done in as expedient a manner as I can -- after all, they are a bit boring :-).

Robert