On Wed, Feb 09, 2022 at 07:23:45AM +0100, Christoph Hellwig wrote: > On Tue, Feb 08, 2022 at 07:30:11PM -0800, Dan Williams wrote: > > Interesting. I had expected that to really fix the refcount problem > > that fs/dax.c would need to start taking real page references as pages > > were added to a mapping, just like page cache. > > I think we should do that eventually. But I think this series that > just attacks the device private type and extends to the device coherent > and p2p enhacements is a good first step to stop the proliferation of > the one off refcount and to allow to deal with the fsdax pages in another > more focuessed series. It is nice, but the other series are still impacted by the fsdax mess - they still stuff pages into ptes without proper refcounts and have to carry nonsense to dance around this problem. I certainly would be unhappy if the amd driver, for instance, gained the fsdax problem as well and started pushing 4k pages into PMDs. Jason
