>>>>>> ((lwpid << 16) | pid).
>> #define PID_MAX         30000
> Is there any reason we can't use larger process IDs?

I can't think of any, except the one already cited (compatability with
userland code that "knows" PIDs are in the range [1..30000]).
Personally, I don't think that reason is enough (though it might be
nice to make PID_MAX settable at kernel config time, so people who are
stuck with such code can build kernels that "work" with it).

/~\ The ASCII				der Mouse
\ / Ribbon Campaign
 X  Against HTML	       mouse@rodents.montreal.qc.ca
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B