From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45006) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eTLk9-0005Vt-5W for qemu-devel@nongnu.org; Mon, 25 Dec 2017 00:56:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eTLk4-0003UH-AL for qemu-devel@nongnu.org; Mon, 25 Dec 2017 00:56:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39386) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eTLk4-0003Tx-4h for qemu-devel@nongnu.org; Mon, 25 Dec 2017 00:56:04 -0500 Date: Mon, 25 Dec 2017 13:55:56 +0800 From: Fam Zheng Message-ID: <20171225055556.GC9418@lemon> References: <20171219084557.9801-1-peterx@redhat.com> <20171219084557.9801-19-peterx@redhat.com> <20171221114246.GO10812@lemon> <20171225051856.GF2443@xz-mi> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171225051856.GF2443@xz-mi> Subject: Re: [Qemu-devel] [RFC v6 18/27] monitor: send event when command queue full List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: Laurent Vivier , Juan Quintela , Markus Armbruster , mdroth@linux.vnet.ibm.com, qemu-devel@nongnu.org, Stefan Hajnoczi , marcandre.lureau@redhat.com, Paolo Bonzini , "Dr . David Alan Gilbert" On Mon, 12/25 13:18, Peter Xu wrote: > On Thu, Dec 21, 2017 at 07:42:46PM +0800, Fam Zheng wrote: > > On Tue, 12/19 16:45, Peter Xu wrote: > > > Set maximum QMP command queue length to 8. If queue full, instead of > > > queue the command, we directly return a "command-dropped" event, telling > > > client that specific command is dropped. > > > > > > Note that this flow control mechanism is only valid if OOB is enabled. > > > If it's not, the effective queue length will always be 1, which strictly > > > follows original behavior of QMP command handling (which never drop > > > messages). > > > > > > Signed-off-by: Peter Xu > > > --- > > > monitor.c | 17 ++++++++++++++++- > > > 1 file changed, 16 insertions(+), 1 deletion(-) > > > > > > diff --git a/monitor.c b/monitor.c > > > index ed9a741d06..b571866659 100644 > > > --- a/monitor.c > > > +++ b/monitor.c > > > @@ -4038,6 +4038,8 @@ static void monitor_qmp_bh_dispatcher(void *data) > > > } > > > } > > > > > > +#define QMP_REQ_QUEUE_LEN_MAX (8) > > > > Is this limit introspectable on QMP? > > Not yet. IMHO it's really QMP internal stuff, and I see no benefit so > far for a client to know about this... A client may need this number to batch (non-oob) commands without worrying about getting command-dropped event. Fam