[Qemu-devel] [PATCH v2 1/5] monitor: split MonitorQAPIEventState

[marcandre.lureau@redhat.com]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Create a separate structure MonitorQAPIEventPending for holding the data
related to pending event.

The next commits are going to reuse this structure for different
throttling implementations.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 monitor.c | 85 +++++++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 50 insertions(+), 35 deletions(-)

diff --git a/monitor.c b/monitor.c
index 1f43263..2d2e030 100644
--- a/monitor.c
+++ b/monitor.c
@@ -174,18 +174,24 @@ typedef struct {
     bool in_command_mode;       /* are we in command mode? */
 } MonitorQMP;
 
+typedef struct {
+    QAPIEvent event;    /* Event being tracked */
+    int64_t last;       /* QEMU_CLOCK_REALTIME value at last emission */
+    QEMUTimer *timer;   /* Timer for handling delayed events */
+    QObject *data;      /* Event pending delayed dispatch */
+} MonitorQAPIEventPending;
+
+typedef struct MonitorQAPIEventState MonitorQAPIEventState;
+
 /*
  * To prevent flooding clients, events can be throttled. The
  * throttling is calculated globally, rather than per-Monitor
  * instance.
  */
-typedef struct MonitorQAPIEventState {
-    QAPIEvent event;    /* Event being tracked */
+struct MonitorQAPIEventState {
     int64_t rate;       /* Minimum time (in ns) between two events */
-    int64_t last;       /* QEMU_CLOCK_REALTIME value at last emission */
-    QEMUTimer *timer;   /* Timer for handling delayed events */
-    QObject *data;      /* Event pending delayed dispatch */
-} MonitorQAPIEventState;
+    void *delay_data;   /* data for the throttle handler */
+};
 
 struct Monitor {
     CharDriverState *chr;
@@ -464,40 +470,41 @@ static void
 monitor_qapi_event_queue(QAPIEvent event, QDict *data, Error **errp)
 {
     MonitorQAPIEventState *evstate;
+    MonitorQAPIEventPending *p;
     assert(event < QAPI_EVENT_MAX);
     int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
 
-    evstate = &(monitor_qapi_event_state[event]);
+    evstate = &monitor_qapi_event_state[event];
+    p = evstate->delay_data;
     trace_monitor_protocol_event_queue(event,
                                        data,
                                        evstate->rate,
-                                       evstate->last,
+                                       p->last,
                                        now);
 
     /* Rate limit of 0 indicates no throttling */
     qemu_mutex_lock(&monitor_lock);
     if (!evstate->rate) {
         monitor_qapi_event_emit(event, QOBJECT(data));
-        evstate->last = now;
     } else {
-        int64_t delta = now - evstate->last;
-        if (evstate->data ||
+        int64_t delta = now - p->last;
+        if (evstate->delay_data ||
             delta < evstate->rate) {
             /* If there's an existing event pending, replace
              * it with the new event, otherwise schedule a
              * timer for delayed emission
              */
-            if (evstate->data) {
-                qobject_decref(evstate->data);
+            if (evstate->delay_data) {
+                qobject_decref(evstate->delay_data);
             } else {
-                int64_t then = evstate->last + evstate->rate;
-                timer_mod_ns(evstate->timer, then);
+                int64_t then = p->last + evstate->rate;
+                timer_mod_ns(p->timer, then);
             }
-            evstate->data = QOBJECT(data);
-            qobject_incref(evstate->data);
+            evstate->delay_data = QOBJECT(data);
+            qobject_incref(evstate->delay_data);
         } else {
             monitor_qapi_event_emit(event, QOBJECT(data));
-            evstate->last = now;
+            p->last = now;
         }
     }
     qemu_mutex_unlock(&monitor_lock);
@@ -509,23 +516,37 @@ monitor_qapi_event_queue(QAPIEvent event, QDict *data, Error **errp)
  */
 static void monitor_qapi_event_handler(void *opaque)
 {
-    MonitorQAPIEventState *evstate = opaque;
+    MonitorQAPIEventPending *p = opaque;
     int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
 
-    trace_monitor_protocol_event_handler(evstate->event,
-                                         evstate->data,
-                                         evstate->last,
+    trace_monitor_protocol_event_handler(p->event,
+                                         p->data,
+                                         p->last,
                                          now);
     qemu_mutex_lock(&monitor_lock);
-    if (evstate->data) {
-        monitor_qapi_event_emit(evstate->event, evstate->data);
-        qobject_decref(evstate->data);
-        evstate->data = NULL;
+    if (p->data) {
+        monitor_qapi_event_emit(p->event, p->data);
+        qobject_decref(p->data);
+        p->data = NULL;
     }
-    evstate->last = now;
+    p->last = now;
     qemu_mutex_unlock(&monitor_lock);
 }
 
+static MonitorQAPIEventPending *
+monitor_qapi_event_pending_new(QAPIEvent event)
+{
+    MonitorQAPIEventPending *p;
+
+    p = g_new0(MonitorQAPIEventPending, 1);
+    p->event = event;
+    p->timer = timer_new(QEMU_CLOCK_REALTIME,
+                         SCALE_MS,
+                         monitor_qapi_event_handler,
+                         p);
+    return p;
+}
+
 /*
  * @event: the event ID to be limited
  * @rate: the rate limit in milliseconds
@@ -540,18 +561,12 @@ monitor_qapi_event_throttle(QAPIEvent event, int64_t rate)
     MonitorQAPIEventState *evstate;
     assert(event < QAPI_EVENT_MAX);
 
-    evstate = &(monitor_qapi_event_state[event]);
+    evstate = &monitor_qapi_event_state[event];
 
     trace_monitor_protocol_event_throttle(event, rate);
-    evstate->event = event;
     assert(rate * SCALE_MS <= INT64_MAX);
     evstate->rate = rate * SCALE_MS;
-    evstate->last = 0;
-    evstate->data = NULL;
-    evstate->timer = timer_new(QEMU_CLOCK_REALTIME,
-                               SCALE_MS,
-                               monitor_qapi_event_handler,
-                               evstate);
+    evstate->delay_data = monitor_qapi_event_pending_new(event);
 }
 
 static void monitor_qapi_event_init(void)
-- 
2.4.3