[Qemu-devel] [RFC 3/3] monitor: remove old entries from event hash table

[marcandre . lureau]

From: Marc-André Lureau <address@hidden>

Do not let the hash table grow without limit, schedule a cleanup for
outdated event.

Signed-off-by: Marc-André Lureau <address@hidden>
---
 monitor.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 48 insertions(+), 3 deletions(-)

diff --git a/monitor.c b/monitor.c
index 7334ffb..6980806 100644
--- a/monitor.c
+++ b/monitor.c
@@ -170,6 +170,8 @@ typedef struct {
     bool in_command_mode;       /* are we in command mode? */
 } MonitorQMP;
 
+typedef struct MonitorQAPIEventState MonitorQAPIEventState;
+
 typedef struct MonitorQAPIEventPending {
     QAPIEvent event;    /* Event being tracked */
     int64_t last;       /* QEMU_CLOCK_REALTIME value at last emission */
@@ -177,8 +179,6 @@ typedef struct MonitorQAPIEventPending {
     QObject *data;      /* Event pending delayed dispatch */
 } MonitorQAPIEventPending;
 
-typedef struct MonitorQAPIEventState MonitorQAPIEventState;
-
 typedef bool (*MonitorQAPIEventDelay) (MonitorQAPIEventState *evstate,
                                        QDict *data);
 /*
@@ -540,6 +540,45 @@ monitor_qapi_event_pending_new(QAPIEvent event)
     return p;
 }
 
+static void monitor_qapi_event_id_remove(void *opaque)
+{
+    MonitorQAPIEventPending *p = opaque;
+    MonitorQAPIEventState *s = &monitor_qapi_event_state[p->event];
+    GHashTable *ht = s->data;
+    GHashTableIter iter;
+    gpointer value;
+
+    g_hash_table_iter_init(&iter, ht);
+    while (g_hash_table_iter_next(&iter, NULL, &value)) {
+        if (value == p) {
+            g_hash_table_iter_remove(&iter);
+            return;
+        }
+    }
+}
+
+/*
+ * do not let the hash table grow, if no later pending event
+ * scheduled, remove the old entry after rate timeout.
+ */
+static void monitor_qapi_event_id_schedule_remove(MonitorQAPIEventPending *p)
+{
+    MonitorQAPIEventState *s = &monitor_qapi_event_state[p->event];
+    int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+    int64_t then = now + s->rate;
+
+    p->timer->cb = monitor_qapi_event_id_remove;
+    timer_mod_ns(p->timer, then);
+}
+
+static void monitor_qapi_event_id_handler(void *opaque)
+{
+    MonitorQAPIEventPending *p = opaque;
+
+    monitor_qapi_event_handler(p);
+    monitor_qapi_event_id_schedule_remove(p);
+}
+
 static bool
 monitor_qapi_event_id_delay(MonitorQAPIEventState *evstate, QDict *data)
 {
@@ -554,7 +593,13 @@ monitor_qapi_event_id_delay(MonitorQAPIEventState 
*evstate, QDict *data)
         g_hash_table_insert(ht, g_strdup(id), p);
     }
 
-    return monitor_qapi_event_pending_update(evstate, p, data);
+    if (monitor_qapi_event_pending_update(evstate, p, data)) {
+        p->timer->cb = monitor_qapi_event_id_handler;
+        return TRUE;
+    } else {
+        monitor_qapi_event_id_schedule_remove(p);
+        return FALSE;
+    }
 }
 
 /*
-- 
2.4.3