On Tue, Jul 02, 2024 at 08:19:01PM +1000, Alistair Popple wrote: > > (B) As long as we have subpage mapcounts, this prevents vmemmap > > optimizations [1]. Is that only used for device-dax for now and are > > there no plans to make use of that for fs-dax? > > I don't have any plans to. This is purely focussed on refcounting pages > "like normal" so we can get rid of all the DAX special casing. > > > (C) We managed without so far :) > > Indeed, although Christoph has asked repeatedly ([1], [2] and likely > others) that this gets fixed and I finally got sick of it coming up > everytime I need to touch something with ZONE_DEVICE pages :) > > Also it removes the need for people to understand the special DAX page > recounting scheme and ends up removing a bunch of cruft as a bonus: > > 59 files changed, 485 insertions(+), 869 deletions(-) > > And that's before I clean up all the pgmap reference handling. It also > removes the pXX_trans_huge and pXX_leaf distinction. So we managed, but > things could be better IMHO. Yes. I can't wait for this series making the finish line. There might be more chance for cleanups and optimizations around ZONE_DEVICE, but this alone is a huge step forward.
