> > how do you know 16 or so is enough?
> 
> It's just a guess.  What I'm assuming is that if you start with 16, and 
> try to never let that drop below 8 (allocating more if you do), then 
> you'll "never" run out.  If you do, well, panic, for now, I guess.
> 
> I'm just trying to offer suggestions that might lead to a better fix 
> than simply disabling map entry merging for kernel maps.

i disabled merging because i thought it was better than
such a guessing. :-(

YAMAMOTO Takashi