On Mon, Mar 15, 2021 at 02:55:01PM +0300, Kirill A. Shutemov wrote:

I'm with Matthew on this. I would really want to drop the number of places
where we call compoud_head(). I hope we can get rid of the page flag
policy hack I made.

I can't see that far ahead too clearly, but I do think that at some
point we'll actually distinguish between folio flags and page flags.
For example, we won't have a FolioHWPoison, because we won't keep a folio
together if one page in it has become defective.  Nor will we have a
PageUptodate because we'll only care about whether a folio is uptodate.
And at that point, we won't want page flag policies.