On Tue, Aug 24, 2021 at 11:59:52AM -0700, Linus Torvalds wrote:

But it is a lot of churn. And it basically duplicates all our page
functions, just to have those simplified versions. And It's very core
code, and while I appreciate the cleverness of the "folio" name, I do
think it makes the end result perhaps subtler than it needs to be.

Maybe I'm biassed by looking at the file system and pagecache side
mostly, but if you look at the progress willy has been making a lot
of the relevant functionality will exist in either folio or page
versions, not both.  A lot of the duplication is to support the
following:

The one thing I do like about it is how it uses the type system to be
incremental.