Re: [PATCH v4 4/4] drm/pagemap: Use dma-map IOVA alloc, link, and sync API for DRM pagemap

Thomas Hellström
2026-02-16T14:33:44Z

On Fri, 2026-02-13 at 12:00 -0800, Matthew Brost wrote:
> On Fri, Feb 13, 2026 at 10:56:46AM -0400, Jason Gunthorpe wrote:
> > On Wed, Feb 11, 2026 at 10:51:32AM -0800, Matthew Brost wrote:
> > > > So to be a little nicer on the IOVA allocator we could use the
> > > > below?
> > > >
> > > > dma_iova_try_alloc(dev, &state->dma_state,
> > > >    (npages - i) *
> > > > PAGE_SIZE >=
> > > >    HPAGE_PMD_SIZE ?
> > > >    HPAGE_PMD_SIZE : 0,
> > > >    (npages - i) *
> > > > PAGE_SIZE);
> > > >
> > >
> > > Yes, we can do that. No reason to force alignment if our copy
> > > code isn't
> > > going to try to use 2M GPU pages.
> >
> > When it comes to this I prefer we try to add alignment information
> > down to the iova allocator because I have other use cases for this
> > alignment optimization.
>
> Trying to parse this - what exactly is your preference here in the
> context of this patch?
>
> i.e., Is original code ok, is Thomas's suggestion ok, or should we do
> something entirely different?
>
> Matt

Interpreting this as Jason would want an alignment parameter to the
IOVA alloctor.

Although that's already the case, albeit somewhat awkwardly named.

Thanks,
Thomas

>
> >
> > Jason