[PATCH v4 00/10] Add MEMORY_DEVICE_COHERENT for coherent device memory mapping

[Christoph Hellwig]

On Thu, Jan 27, 2022 at 02:32:58PM -0800, Andrew Morton wrote:
> On Wed, 26 Jan 2022 21:09:39 -0600 Alex Sierra <alex.sierra at amd.com> wrote:
> 
> > This patch series introduces MEMORY_DEVICE_COHERENT, a type of memory
> > owned by a device that can be mapped into CPU page tables like
> > MEMORY_DEVICE_GENERIC and can also be migrated like
> > MEMORY_DEVICE_PRIVATE.
> 
> Some more reviewer input appears to be desirable here.
> 
> I was going to tentatively add it to -mm and -next, but problems. 
> 5.17-rc1's mm/migrate.c:migrate_vma_check_page() is rather different
> from the tree you patched.  Please redo, refresh and resend?

I really hate adding more types with the weird one off page refcount.
We need to clean that mess up first.