Re: [Qemu-devel] [PATCH 3/5] Add getfd and closefd monitor commands

[Mark McLoughlin <markmc@redhat.com>]

On Wed, 2009-07-08 at 22:52 +0300, Avi Kivity wrote:
> On 07/08/2009 09:50 PM, Anthony Liguori wrote:
> > Avi Kivity wrote:
> >> If the client is written in a high level language it's also 
> >> reasonable that some buffering would take place and you'd see a 
> >> single packet containing multiple commands, or a command split into 
> >> multiple packets.  Therefore I'd like to avoid any assumptions in 
> >> this area.
> >
> > That misses the point though.  We process one command at a time in the 
> > monitor so we only need to buffer one fd at a time.  When we start to 
> > process multiple commands at once in the monitor, we'll do so with 
> > multiple monitor states and we'll want to have one fd per monitor state.
> 
> Again I'm thinking of the client.  If two client threads issue commands 
> in parallel there'd be >1 fds on the wire.  But qemu can consume them 
> sequentially so I agree queue may hold just a single fd.

Okay, it sounds like these patches didn't get applied for 0.11 because
of confusion over the conclusion here.

My take on it is that we're all agreed that it's never valid with the
current monitor protocol for a client to queue up multiple fds. It's a
synchronous protocol, you can't send multiple commands at once.

I'll re-post the patches in reply to this.

Thanks,
Mark.