Re: [PATCH v4 3/4] vhost-user: add shared_object msg

[Michael S. Tsirkin]

On Mon, Jul 17, 2023 at 01:42:02PM +0200, Albert Esteve wrote:
> Hi Michael,
> 
> True. It may be a good idea to impose a limit in the number of entries that 
> can
> be added to the table.
> And fail to add new entries once it reaches the limit.
> 
> Not sure what would be a good limit though. For example, 
> https://www.kernel.org
> /doc/html/v4.9/media/uapi/v4l/vidioc-reqbufs.html#c.v4l2_requestbuffers
> does not limit the number of buffers that can be allocated simultaneously, it
> is an unsigned 32-bits value.
> However, I guess 16-bits (65535) would suffice to cover the vast majority of
> usecases. Or even lower, and
> can be adjusted later, as this API gets (more) used.
> 
> Does that make sense?
> 
> Thanks.
> BR,
> Albert

let's not top-post please.

Maybe. Another concern is qemu running out of FDs with a bad backend.

Question: why does qemu have to maintain these UUIDs in its memory?

Can't it query the backend with UUID and get the fd back?

And then, the hash table in QEMU becomes just a cache
to speed up lookups.

-- 
MST