Re: [PATCH 21/22] mm: remove the HMM config option

[Christoph Hellwig]

On Thu, Jun 13, 2019 at 08:01:55PM +0000, Jason Gunthorpe wrote:
> On Thu, Jun 13, 2019 at 11:43:24AM +0200, Christoph Hellwig wrote:
> > All the mm/hmm.c code is better keyed off HMM_MIRROR.  Also let nouveau
> > depend on it instead of the mix of a dummy dependency symbol plus the
> > actually selected one.  Drop various odd dependencies, as the code is
> > pretty portable.
> 
> I don't really know, but I thought this needed the arch restriction
> for the same reason get_user_pages has various unique arch specific
> implementations (it does seem to have some open coded GUP like thing)?
> 
> I was hoping we could do this after your common gup series? But sooner
> is better too.

Ok, I've added the arch and 64-bit dependency back in for now.  It does
not look proper to me, and is certainly underdocumented, but the whole
pagetable walking code will need a lot of love eventually anyway, and
the Kconfig stuff for it can be done properly then.