Re: pte-highmem-5

Linus Torvalds
2002-01-16T19:12:46Z

On Wed, 16 Jan 2002, Andrea Arcangeli wrote:
>
> > - do the highmem pte bouncing only for CONFIG_X86_PAE: with less then 4GB
> > of RAM this doesn't seem to matter all that much (rule of thumb: we
> > need about 1% of memory for page tables). Again, this will simplify
> > things, as it will make other architectures not have to worry about the
> > change.
>
> I'm not sure how simpler it will make things and I'd prefer to keep the
> pte in highmem also with 4G to be more generic

I agree that this will not make things simpler, it will just streamline
and speed up some of the VM paths for people who just don't need it.

A lot of HIGHMEM users have just 1GB and use HIGHMEM to get at the last
few megs, so..

It might make sense to make it an independent config option, and possibly
just split up the highmem question a bit more (ie make the choices be
something like "none", "4G", "4G+pte-kmap" or "64G(with pte-kmap)").

Linus