Re: [PATCH v6 08/14] mm/gup: do not migrate zero page

[Jason Gunthorpe]

On Wed, Jan 20, 2021 at 09:26:41AM -0500, Pavel Tatashin wrote:

> I thought about this, and it would code a little cleaner. But, the
> reason I did not is because zero_page is perfectly pinnable, it is not
> pinnable only when it is in a movable zone (and it should not be in a
> movable zones for other reasons as well), but that is another bug that
> needs to be resolved, and once that bug is resolved this condition can
> be removed from gup migration.

My point is you've defined the zero page to be pinnable no matter what
zone it is in, so is_pinnable(zero_page) == true

Jason