From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56997) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eRzFc-0005bD-LY for qemu-devel@nongnu.org; Thu, 21 Dec 2017 06:43:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eRzFX-00017r-Gn for qemu-devel@nongnu.org; Thu, 21 Dec 2017 06:43:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53836) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eRzFX-00014t-Ax for qemu-devel@nongnu.org; Thu, 21 Dec 2017 06:42:55 -0500 Date: Thu, 21 Dec 2017 19:42:46 +0800 From: Fam Zheng Message-ID: <20171221114246.GO10812@lemon> References: <20171219084557.9801-1-peterx@redhat.com> <20171219084557.9801-19-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171219084557.9801-19-peterx@redhat.com> 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: qemu-devel@nongnu.org, Stefan Hajnoczi , "Daniel P . Berrange" , Paolo Bonzini , Juan Quintela , mdroth@linux.vnet.ibm.com, Eric Blake , Laurent Vivier , Markus Armbruster , marcandre.lureau@redhat.com, "Dr . David Alan Gilbert" 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? Fam