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

Matthew Brost
2026-02-13T20:00:48Z

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

>
> Jason