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

[Damien Le Moal]

On 2020/05/14 11:20, Martin K. Petersen wrote:
> 
> 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.

Sent a patch :)

> 
> 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.

Yes. Will look at that too.

Thanks !

> 


-- 
Damien Le Moal
Western Digital Research