On Fri, Feb 16, 2024 at 02:00:31PM -0800, Sidhartha Kumar wrote: > On 2/16/24 1:55 PM, Matthew Wilcox wrote: > > On Fri, Feb 16, 2024 at 01:13:18PM -0800, Sidhartha Kumar wrote: > > > Use migrate_pfn_to_folio() so we can work with folios directly in > > > __migrate_device_pages(). > > > > i don't understand why this would be correct if we have multipage > > folios. > > > > Alistair mentioned that he is working on order > 0 device page support so I > was under the impression that currently device pages are only order 0. That might well be true, but I'm *very* uncomfortable with doing a folio conversion in core MM that won't work with large folios. We need to consider what will happen with large device folios. (for filesystems, I am less bothered. Individual filesystems control whether they see large folios or not, and for lesser filesystems it may never be worth converting them to support large folios)
