On Wed, 18 Apr 2018, Matthew Wilcox wrote: > As suggested by Kirill, make page_type a bitmask. Because it starts out > life as -1 (thanks to sharing the storage with _mapcount), setting a > page flag means clearing the appropriate bit. This gives us space for > probably twenty or so extra bits (depending how paranoid we want to be > about _mapcount underflow). Could we use bits in the page->flags for this? We could remove the node or something else from page->flags. And the slab bit could also be part of the page type. The page field handling gets more and more bizarre.
