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 <[email protected]> --- 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
