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: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1444921716-9511-7-git-send-email-armbru@redhat.com>
This commit is contained in:
Markus Armbruster 2015-10-15 17:08:35 +02:00
parent a24712af54
commit 7de0be6573

View File

@ -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)