[PATCH v1 0/3] udmabuf: Add support for page migration out of movable zone or CMA

[Jason Gunthorpe]

On Thu, Aug 24, 2023 at 08:30:17PM +0200, David Hildenbrand wrote:
> On 24.08.23 08:31, Kasireddy, Vivek wrote:
> > Hi David,
> > 
> > > 
> > > > > - Add a new API to the backing store/allocator to longterm-pin the page.
> > > > >     For example, something along the lines of
> > > shmem_pin_mapping_page_longterm()
> > > > >     for shmem as suggested by Daniel. A similar one needs to be added for
> > > > >     hugetlbfs as well.
> > > > 
> > > > This may also be reasonable.
> > > 
> > > Sounds reasonable to keep the old API (that we unfortunately have) working.
> > I agree; I'd like to avoid adding new APIs unless absolutely necessary. Given this,
> > and considering the options I have mentioned earlier, what would be your
> > recommendation for how page migration needs to be done in udmabuf driver?
> 
> I guess using proper APIs for shmem and hugetlb. So, turning roughly what
> you have in patch#1 for now into common code, and only calling into that
> from udmabug.

This is a lot of work for an obscure uapi :\

Jason