Filtering bits in set_pte_at()

[Benjamin Herrenschmidt]

On Mon, 2009-11-02 at 23:45 +0000, Hugh Dickins wrote:
> > IE. update_mmu_cache() would be more generally useful if it took the
> > ptep instead of the pte. Of course, I'm sure some embedded archs are
> > going to cry for the added load here ... 
> > 
> > I like your idea. I'll look into doing a patch converting it and
> will
> > post it here.
> 
> Well, I wasn't proposing
> 
>                 update_mmu_cache(vma, address, ptep);
> but
>                 update_mmu_cache(vma, address, *ptep);
> 
> which may not meet your future idea, but is much less churn for now
> i.e. no change to any of the arch's update_mmu_cache(),
> just a change to some of its callsites. 

I see... but if we go that way, I think we may as well do the whole
churn... I'll have a look at how bad it is.

Cheers,
Ben.