Re: RFC: stop having a single global page size

[Justin Cormack <justin%specialbusservice.com@localhost>]

On Fri, Jan 31, 2014 at 9:14 AM, Martin Husemann <martin%duskware.de@localhost> 
wrote:
> On Fri, Jan 31, 2014 at 12:59:15AM -0800, Matt Thomas wrote:
>> Why would anyone want this?  Say you have a system in which the MMU can have
>> per translation table page sizes.  a 16KB page size might be desirable for 
>> the
>> kernel and for LP64 processes.  If you are running a ILP32 process, possibly
>> of an older architecture, you might want to use a 4KB page size.
>
> I guess another usage is a (huge) framebuffer/aperture mmap'd by the
> userland driver, where you could easily save a lot TLB entries by using
> 1 MB pages (or bigger) instead of 4/8k ones. I think Solaris does this.

Linux maps the kernel with 4MB pages to save TLB entries too, I believe.

Justin