Why
They are used by the i915 DRM driver in Linux 6.6 (although this change was only backported with Linux 6.7 DRM drivers...).
How
struct folio simply wraps struct page for now.
struct folio_batch is the same as struct pagevec but it works with struct folio instead of struct page directly.
This is part of the update of DRM drivers to Linux 6.7.
Sponsored by: The FreeBSD Foundation