On Mon, Jun 16, 2025 at 12:07:42PM -0400, Mike Snitzer wrote: > But that's OK... my test bdev is a bad example (archaic VMware vSphere > provided SCSI device): it doesn't reflect expected modern hardware. > > But I just slapped together a test pmem blockdevice (memory backed, > using memmap=6G!18G) and it too has dma_alignment=511 That's the block layer default when not overriden by the driver, I guess pmem folks didn't are enough. I suspect it should not have any alignment requirements at all. > I'd like NFSD to be able to know if its bvec is dma-aligned, before > issuing DIO writes to underlying XFS. AFAIK I can do that simply by > checking the STATX_DIOALIGN provided dio_mem_align... Exactly.
