[dm-devel] [PATCHv5 00/14] dm-zoned: metadata version 2

[Martin K. Petersen]

Damien,

> Indeed. It is an NVMe M.2 consumer grade SSD. Nothing fancy. If you
> look at nvme/host/core.c nvme_update_disk_info(), you will see that
> io_opt is set to the block size... This is probably abusing this
> limit. So I guess the most elegant fix may be to have nvme stop doing
> that ?

Yeah, I'd prefer for io_opt to only be set if the device actually
reports NOWS.

The purpose of io_min is to be the preferred lower I/O size
boundary. One should not submit I/Os smaller than this.

And io_opt is the preferred upper boundary for I/Os. One should not
issue I/Os larger than this value. Setting io_opt to the logical block
size kind of defeats that intent.

That said, we should probably handle the case where the pbs gets scaled
up but io_opt doesn't more gracefully.

-- 
Martin K. Petersen	Oracle Linux Engineering