On Wed, Sep 08, 2021 at 06:20:49PM +0300, Denis Plotnikov wrote:
On 08.09.2021 16:22, Stefano Garzarella wrote:
Message bounced, I use new Denis's email address.
On Wed, Sep 08, 2021 at 03:17:16PM +0200, Stefano Garzarella wrote:
Hi Denis,
I just found this discussion since we still have the following
line in hw/core/machine.c:
{ "vhost-blk-device", "seg_max_adjust", "off"}
IIUC it was a typo, and I think we should fix it since in the
future we can have `vhost-blk-device`.
So, I think we have 2 options:
1. remove that line since for now is useless
2. replace with "vhost-scsi"
I'm not sure which is the best, what do you suggest?
Thanks,
Stefano
Hi Stefano
I prefer to just remove the line without replacing. This will keep
things exactly like it is now.
Replacing with "vhost-scsi" will affect seg_max (limit to 126) on
newly created VMs with machine types using "hw_compat_4_2" and older.
Now, because of the typo (error), their seg-max is queue-size
dependent. I'm not sure, if replacing the line may cause any problems,
for example on migration: source (queue-size 256, seg max 254) ->
destination (queue-size 256, seg max 126). But it will definitely
introduce two different behaviors for VMs with "hw_compat_4_2" and
older. So, I'd choose the lesser of two evils and keep the things like
it's now.
Yep, make sense. It was the same concern I had.
Do you want to send a patch to remove it with this explanation?
Thanks for the clarification,
Stefano
