On Fri, Aug 27, 2021 at 02:41:11PM -0700, Dan Williams wrote: > On Fri, Aug 27, 2021 at 11:47 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > On Fri, Aug 27, 2021 at 10:07:16AM -0400, Johannes Weiner wrote: > > > We have the same thoughts in MM and growing memory sizes. The DAX > > > stuff said from the start it won't be built on linear struct page > > > mappings anymore because we expect the memory modules to be too big to > > > manage them with such fine-grained granularity. > > > > Well, I did. Then I left Intel, and Dan took over. Now we have a struct > > page for each 4kB of PMEM. I'm not particularly happy about this change > > of direction. > > Page-less DAX left more problems than it solved. Meanwhile, > ZONE_DEVICE has spawned other useful things like peer-to-peer DMA. ZONE_DEVICE has created more problems than it solved. Pageless memory is a concept which still needs to be supported, and we could have made a start on that five years ago. Instead you opted for the expeditious solution.
