On Thu, Mar 14, 2024 at 12:11:18PM +0100, Hannes Reinecke wrote: > On 3/13/24 19:28, Matthew Wilcox wrote: > > None of those things are needed for brd's uses. All brd needs is to > > be able to allocate, kmap and free chunks of memory. Unless there are > > plans to do more than this. > > The primary goal of my patchset is to make brd a test-bed for the LBS work; > devices with a sector size larger than 4k are really hard to come > by. But really, it's just a testbed, and I'm not sure whether there's > a need for that in the general audience. > I can resubmit if you want ... > > As for the memory overhead, I guess it only makes a noticable difference > when moving to hugepages, and have brd allocate hugepages only. > But that is future work for sure. As I said, this is talking about a memdesc future where struct page is a mere 8 bytes and most of its contents are reserved to the MM. At this point, there's no extra overhead to your patch, but there would be when we get there. So I don't think the folio conversion is necessary, but I think supporting larger sector sizes in brd is a worthwhile extension.
