Re: [PATCH v3] vfio/type1: optimize vfio_pin_pages_remote() for huge folio

[Peter Xu <peterx@redhat.com>]

Hi, Alex,

On Tue, May 20, 2025 at 08:07:19AM -0600, Alex Williamson wrote:
> Peter, David, if you wouldn't mind double checking the folio usage
> here, I'd appreciate it.  The underlying assumption used here is that
> folios always have physically contiguous pages, so we can increment at
> the remainder of the folio_nr_pages() rather than iterate each page.

Yes I think so.  E.g., there's comment above folio definition too:

/**
 * struct folio - Represents a contiguous set of bytes.
 * ...
 * A folio is a physically, virtually and logically contiguous set
 * of bytes...
 */

For 1G, I wonder if in the future vfio can also use memfd_pin_folios()
internally when possible, e.g. after stumbled on top of a hugetlb folio
when filling the batch.

Thanks,

-- 
Peter Xu