Re: kmem changes in -current

[Radoslaw Kujawa <radoslaw.kujawa%c0ff33.net@localhost>]

Hi.

On 7 lut 2012, at 17:37, Michael L. Hitch wrote:

> I believe that the solution for this is for each m68k port to allocated extra 
> kernel pt pages during their mmu setup.  A simple calculation of physical 
> memory size in pages divided by the number of PTEs per page. That should 
> provide enough kernel address space to allow pmap_init() to allocate the 
> memory for the pmap initialization.  [The current default size of the kmem 
> arena is roughly 2/3 the size of the physical memory, so a closer 
> approximation could include that in the calculation.]


This is not directly related, but if we are speaking about m68k pmap... There 
are severe problems in the setups where large amount of kernel address space is 
needed. Typical case on amiga port is situation where user has a lot of Zorro 
I/O boards, or just a large board. Currently, it is not even possible to boot 
the NetBSD on such machines, because M68K_PTBASE is statically set to 
0x10000000. For most setups it is possible to work around the problem by moving 
PTBASE to a higher address. Now I wonder, if it is possible to fix the 68k pmap 
implementation, to allow dynamic setting of M68K_PTBASE?

The problem was discussed before in this thread: 
http://mail-index.netbsd.org/port-amiga/2011/07/22/msg007578.html

-- 
Best regards,
Radoslaw Kujawa