Re: [Qemu-devel] [RFC v2 15/22] monitor: send event when request queue full

[Stefan Hajnoczi]

On Fri, Sep 29, 2017 at 11:38:37AM +0800, Peter Xu wrote:
> Set maximum QMP request queue length to 8.  If queue full, instead of
> queue the command, we directly return a "request-dropped" event, telling
> client that specific command is dropped.
> 
> Signed-off-by: Peter Xu <address@hidden>
> ---
>  monitor.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/monitor.c b/monitor.c
> index 1e9a6cb6a5..d9bed31248 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -3971,6 +3971,8 @@ static void monitor_qmp_bh_dispatcher(void *data)
>      }
>  }
>  
> +#define  QMP_ASYNC_QUEUE_LEN_MAX  (8)

Why 8?

My understanding is that this patch series is not about asynchronous QMP
commands.  Instead it's about executing certain commands immediately in
the parser thread.

Therefore, I suggest hardcoding length 1 for now and not calling it
"async".  You may also be able to simplify the code since a queue isn't
actually needed.