@@ -4029,6 +4029,8 @@ static void monitor_qmp_bh_dispatcher(void *data)
}
}
+#define QMP_REQ_QUEUE_LEN_MAX (8)
+
static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens,
void *opaque)
{
@@ -4061,6 +4063,21 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens,
req_obj->id = id;
req_obj->req = req;
+ if (qmp_oob_enabled(mon)) {
+ /* Drop the request if queue is full. */
+ if (mon->qmp.qmp_requests->length >= QMP_REQ_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,
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. 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 <peterx@redhat.com> --- monitor.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)