Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

Andrew Morton
2007-03-07T09:08:25Z

On Wed, 07 Mar 2007 09:51:57 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote:

> > > Dirty page accounting doesn't work either on
> > > non-linear mappings
> >
> > It doesn't? Confused - these things don't have anything to do with each
> > other do they?
>
> Look in page_mkclean(). Where does it handle non-linear mappings?
>

OK, I'd forgotten about that. It won't break dirty memory accounting,
but it'll potentially break dirty memory balancing.

If we have the wrong page (due to nonlinear), page_check_address() will
fail and we'll leave the pte dirty. That puts us back to the pre-2.6.17
algorithms and I guess it'll break the msync guarantees.

Peter, I thought we went through the nonlinear problem ages ago and decided
it was OK?