Hi.

> 2) I have to put a call to the VM system in init_mach(). This is because
>   we need to allocate 96kB + 32kB of slop, wired down, physically
>   contigious and aligned on a 32kB boundary; the reason for putting it
>   in init_mach() is that it has to be allocated before the buffers, so
>   it gets into the first 8MB of memory (buffers take up 6MB on my box,
>   along with kernel space that's over 8MB). 28kB of the slop can be freed 
>   in px_attach() (or the whole shebang, if it's not used). I'm convinced 
>   there's a better way to do this.

That's the exact case which bus_dma(9) interface targets.  It can avoid
to put #if NPX > 0 thing inside mach_init() routines to reserve a region
of constrained memory arena.

Tohru Nishimura
Nara Institute of Science and Technology