>  + Should we add another sysctl_rdstruct()-type function (maybe
>    sysctl_rdminstruct()?) that would only return min(data_size,
>    request_size) so min() isn't used in lots of places and it's
>    obvious which sysctls may return short data.  

Yes..

>  + All the fields in uvmexp are "int".  Is this big enough?  Sure MAXINT
>    pages on a box is a _big_ number, but Compaq have a box that can
>    handle 256GB of RAM - that's 2^25 pages already...

yah, but there's maybe a decade of headroom there..

>  + Everything in uvmexp is nicely grouped together - I'd still like to
>    make a struct uvmexp2 with fixed size fields and the same rules as
>    struct kinfo_proc2 where new fields can only be added to the end.

agreed.  these counters can be int in uvmexp and uint64_t in uvmexp2,
and then they can grow to larger types in the kernel implementation
when it makes sense for them to grow, without affecting the ABI.

						- Bill