Commit 7de0be65 authored by Markus Armbruster's avatar Markus Armbruster
Browse files

monitor: Throttle event VSERPORT_CHANGE separately by "id" 



VSERPORT_CHANGE is emitted when the guest opens or closes a
virtio-serial port.  The event's member "id" identifies the port.

When several events arrive quickly, throttling drops all but the last
of them.  Because of that, a QMP client must assume that *any* port
may have changed state when it receives a VSERPORT_CHANGE event and
throttling may have happened.

Make the event more useful by throttling it for each port separately.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <1444921716-9511-7-git-send-email-armbru@redhat.com>
parent a24712af

monitor.c

+23 −4
Original line number Diff line number Diff line
@@ -181,7 +181,8 @@ typedef struct { 
 * instance.

 */

typedef struct MonitorQAPIEventState {

    QAPIEvent event;    /* Event being tracked */

    QAPIEvent event;    /* Throttling state for this event type and... */

    QDict *data;        /* ... data, see qapi_event_throttle_equal() */

    QEMUTimer *timer;   /* Timer for handling delayed events */

    QDict *qdict;       /* Delayed event (if any) */

} MonitorQAPIEventState;
@@ -490,7 +491,8 @@ monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp) 
        /* Unthrottled event */

        monitor_qapi_event_emit(event, qdict);

    } else {

        MonitorQAPIEventState key = { .event = event };

        QDict *data = qobject_to_qdict(qdict_get(qdict, "data"));

        MonitorQAPIEventState key = { .event = event, .data = data };



        evstate = g_hash_table_lookup(monitor_qapi_event_state, &key);

        assert(!evstate || timer_pending(evstate->timer));
@@ -517,6 +519,8 @@ monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp) 


            evstate = g_new(MonitorQAPIEventState, 1);

            evstate->event = event;

            evstate->data = data;

            QINCREF(evstate->data);

            evstate->qdict = NULL;

            evstate->timer = timer_new_ns(QEMU_CLOCK_REALTIME,

                                          monitor_qapi_event_handler,
@@ -551,6 +555,7 @@ static void monitor_qapi_event_handler(void *opaque) 
        timer_mod_ns(evstate->timer, now + evconf->rate);

    } else {

        g_hash_table_remove(monitor_qapi_event_state, evstate);

        QDECREF(evstate->data);

        timer_free(evstate->timer);

        g_free(evstate);

    }
@@ -561,8 +566,13 @@ static void monitor_qapi_event_handler(void *opaque) 
static unsigned int qapi_event_throttle_hash(const void *key)

{

    const MonitorQAPIEventState *evstate = key;

    unsigned int hash = evstate->event * 255;



    return evstate->event * 255;

    if (evstate->event == QAPI_EVENT_VSERPORT_CHANGE) {

        hash += g_str_hash(qdict_get_str(evstate->data, "id"));

    }



    return hash;

}



static gboolean qapi_event_throttle_equal(const void *a, const void *b)
@@ -570,7 +580,16 @@ static gboolean qapi_event_throttle_equal(const void *a, const void *b) 
    const MonitorQAPIEventState *eva = a;

    const MonitorQAPIEventState *evb = b;



    return eva->event == evb->event;

    if (eva->event != evb->event) {

        return FALSE;

    }



    if (eva->event == QAPI_EVENT_VSERPORT_CHANGE) {

        return !strcmp(qdict_get_str(eva->data, "id"),

                       qdict_get_str(evb->data, "id"));

    }



    return TRUE;

}



static void monitor_qapi_event_init(void)