From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36224) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dxmAJ-0006ef-FL for qemu-devel@nongnu.org; Thu, 28 Sep 2017 23:40:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dxmAE-0007K3-F7 for qemu-devel@nongnu.org; Thu, 28 Sep 2017 23:40:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47636) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dxmAE-0007JY-A6 for qemu-devel@nongnu.org; Thu, 28 Sep 2017 23:40:34 -0400 From: Peter Xu Date: Fri, 29 Sep 2017 11:38:37 +0800 Message-Id: <20170929033844.26935-16-peterx@redhat.com> In-Reply-To: <20170929033844.26935-1-peterx@redhat.com> References: <20170929033844.26935-1-peterx@redhat.com> Subject: [Qemu-devel] [RFC v2 15/22] monitor: send event when request queue full List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , "Daniel P . Berrange" , Stefan Hajnoczi , Fam Zheng , Juan Quintela , mdroth@linux.vnet.ibm.com, peterx@redhat.com, Eric Blake , Laurent Vivier , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Markus Armbruster , "Dr . David Alan Gilbert" List-ID: 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 --- 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) + static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, void *opaque) { @@ -4002,6 +4004,19 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, req_obj->id = id; req_obj->req = req; + /* Drop the request if queue is full. */ + if (mon->qmp_requests->length >= QMP_ASYNC_QUEUE_LEN_MAX) { + const char *id_str = qobject_get_try_str(id); + + qapi_event_send_request_dropped(id_str ? id_str : "", + REQUEST_DROP_REASON_QUEUE_FULL, + NULL); + qobject_decref(id); + qobject_decref(req); + g_free(req_obj); + return; + } + /* * Put the request to the end of queue so that requests will be * handled in time order. Ownership for req_obj, req, id, -- 2.13.5