Re: mm question

[Martin J. Bligh]

>> > I was hoping for something more elegant, but I am not adverse to writing
>> > my own get_free_page_from_range().
>> 
>> Thats not a trivial task.
> 
> Better than giving up.. Unfortunately looking around in
> linux/Documentation and drivers did not yield much in terms of
> explanation. I know I can use mem_map_reserve to reserve a page but I
> don't know how to get page struct from a physical address nor which lock
> to use when messing with this.

If you don't have any ISA DMA going on in the system, you might consider
bastardising the ZONE_DMA page range by moving the boundary up to
64Mb, then fixing the allocator not to fail back ZONE_NORMAL et al 
allocations to ZONE_DMA. Thus what was originally ZONE_DMA becomes 
a sort of ZONE_NO_DMA. Not in the slightest bit pretty, but it might be easier 
to implement. Depends if you ever want it to get back into the main tree,
I guess ;-)

M.