On Thu, Jul 20, 2023 at 2:56 PM Michal Prívozník <mpriv...@redhat.com>
wrote:

> On 7/20/23 08:22, Han Han wrote:
> > These two attributes are supported for vhost-user-blk as well.
> >
> > Signed-off-by: Han Han <h...@redhat.com>
> > ---
> >  docs/formatdomain.rst | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> > index 4af0b82569..447ab32c01 100644
> > --- a/docs/formatdomain.rst
> > +++ b/docs/formatdomain.rst
> > @@ -3275,9 +3275,9 @@ paravirtualized driver is specified via the
> ``disk`` element.
> >        "virtio" ``bus`` and "pci" or "ccw" ``address`` types.
> :since:`Since 1.2.8
> >        (QEMU 2.1)`
> >     -  The optional ``queues`` attribute specifies the number of virt
> queues for
> > -      virtio-blk. ( :since:`Since 3.9.0` )
> > +      virtio-blk or vhost-user-blk. ( :since:`Since 3.9.0` )
>
> This doesn't feel right. The vhost-user-blk disk was introduced fairly
> recently and 3.9.0 is just ancient. Digging into commits, vhost-user-blk
> disk was introduced in v7.1.0 and I didn't check whether it supported
> the attribute from the very beginning.
>
> Thank you for pointing this out.  It looks libvirt allows the user to set
the queues for
all the bus=='virtio':
https://gitlab.com/libvirt/libvirt/-/blob/v7.1.0/src/conf/domain_validate.c#L465

So vhost-user-blk could use the queues at the beginning.

> I think if we want to document the attribute then we should probably do
> it like this:
>
> The optional ``queues`` attribute specifies the number of virt queues
> for virtio-blk ( :sinnce:`Since 3.9.0) or vhost-user-blk ( :since:`Since
> X.Y.Z` ).
>
> >     -  The optional ``queue_size`` attribute specifies the size of each
> virt
> > -      queue for virtio-blk. ( :since:`Since 7.8.0` )
> > +      queue for virtio-blk or vhost-user-blk. ( :since:`Since 7.8.0` )
> >     -  For virtio disks, `Virtio-related options`_ can also
> >        be set. ( :since:`Since 3.5.0` )
> >     -  The optional ``metadata_cache`` subelement controls aspects
> related to the
>
> I have not checked this later hunk.
>
> Michal
>
>

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