Making external (alien) RAM cacheable

Hi all,

I have 1G physical memory on the system. out of which only 200 MB is known to the linux kernel. Now I have some buffers in the other 824 MB of memory. These buffers would be inherently non cacheable because that memory is unknow to the system. I was wondering how can I include some of the buffers in that memory in the page table so that they become cacheable.

Any inputs would be highly appreciated.

Thanks
Aby

I know that I need to mess here with mmap (), but dont know exactly what/how it can be done.