Subject: Re: Multiple page sizes and the pmap API
To: Jason R Thorpe <>
From: Wojciech Puchar <>
List: tech-kern
Date: 12/07/2001 18:09:03
> Several platforms support multiple page sizes.  Examples are
> the i386, which has 4K and 4M pages, the ARM which has 4K,

ARM has 4 subpages too isn't it?

> 64K, and 1M pages, and the MIPS which has 4K, 8K, 16K, ... pages.
> I would like to add support to the pmap API for using these larger
> page sizes.

will be an EXCELLENT idea. for example large 20.5MB file could be mapped
as 2*4MB+ 640*4K on i386 or 20*1M+8*64k on ARM

it would make GREAT speedup.

> With this infrastructure in place, it would be pretty short work to
> get the devpager using large pages.  Chuq and I also discussed some
> ideas for using large pages for other types of mappings (vnode and
> anonymous memory), but they still depend on having this infrastructure

what about mapping regular data this way?