On Mon, Feb 08, 2021 at 07:26:25PM -0400, Jason Gunthorpe wrote: > > > page_mkclean() has some technique to make the notifier have the right > > > size without becoming entangled in the PTL locks.. > > > > Right. I guess it's because dax doesn't have "struct page*" on the > > back, so it > > It doesn't? I thought DAX cases did? File system DAX has a struct page, device DAX does not. Which means everything using iomap should have a page available, but i'm adding Dan as he should know the details :)