Make the server watchdog a standalone thread that doesn't need messaging

src/generator.c

@@ -130,7 +130,8 @@ struct proxy_instance {
 struct generator_data {
 	mutex_t lock; /* Lock protecting linked lists */
 	proxy_instance_t *proxy_list; /* Linked list of all active proxies */
-	int proxy_notify_id;	// Globally increasing notify id
+	int proxy_notify_id;	/* Globally increasing notify id */
+	server_instance_t *si;	/* Current server instance */
 	ckmsgq_t *srvchk;	// Server check message queue
 };
 
@@ -264,7 +265,6 @@ static int gen_loop(proc_instance_t *pi)
 	int sockd = -1, ret = 0, selret;
 	unixsock_t *us = &pi->us;
 	ckpool_t *ckp = pi->ckp;
-	gdata_t *gdata = ckp->data;
 	bool started = false;
 	char *buf = NULL;
 	connsock_t *cs;
@@ -291,7 +291,6 @@ reconnect:
 
 retry:
 	Close(sockd);
-	ckmsgq_add(gdata->srvchk, si);
 
 	do {
 		selret = wait_recv_select(us->sockd, 5);
@@ -1692,8 +1691,38 @@ out:
 	return ret;
 }
 
+/* Check which servers are alive, maintaining a connection with them and
+ * reconnect if a higher priority one is available. */
+static void *server_watchdog(void *arg)
+{
+	ckpool_t *ckp = (ckpool_t *)arg;
+	gdata_t *gdata = ckp->data;
+
+	while (42) {
+		server_instance_t *best = NULL;
+		ts_t timer_t;
+		int i;
+
+		cksleep_prepare_r(&timer_t);
+		for (i = 0; i < ckp->btcds; i++) {
+			server_instance_t *si  = ckp->servers[i];
+
+			/* Have we reached the current server? */
+			if (server_alive(ckp, si, true) && !best)
+				best = si;
+		}
+		if (best && best != gdata->si) {
+			gdata->si = best;
+			send_proc(ckp->generator, "reconnect");
+		}
+		cksleep_ms_r(&timer_t, 5000);
+	}
+	return NULL;
+}
+
 static int server_mode(ckpool_t *ckp, proc_instance_t *pi)
 {
+	pthread_t pth_watchdog;
 	server_instance_t *si;
 	int i, ret;
 
@@ -1710,6 +1739,7 @@ static int server_mode(ckpool_t *ckp, proc_instance_t *pi)
 		cksem_post(&si->cs.sem);
 	}
 
+	create_pthread(&pth_watchdog, server_watchdog, ckp);
 	ret = gen_loop(pi);
 
 	for (i = 0; i < ckp->btcds; i++) {
@@ -1778,34 +1808,6 @@ static int proxy_mode(ckpool_t *ckp, proc_instance_t *pi)
 	return ret;
 }
 
-/* Tell the watchdog what the current server instance is, check which servers
- * are alive, maintaining a connection with them and reconnect if a higher
- * priority one is available. */
-static void server_watchdog(ckpool_t *ckp, server_instance_t *cursi)
-{
-	server_instance_t *best = NULL;
-	static time_t last_t = 0;
-	time_t now_t;
-	int i;
-
-	/* Rate limit to checking only once every 5 seconds */
-	now_t = time(NULL);
-	if (now_t <= last_t + 5)
-		return;
-
-	last_t = now_t;
-
-	for (i = 0; i < ckp->btcds; i++) {
-		server_instance_t *si  = ckp->servers[i];
-
-		/* Have we reached the current server? */
-		if (server_alive(ckp, si, true) && !best)
-			best = si;
-	}
-	if (best && (!cursi || cursi->id > best->id))
-		send_proc(ckp->generator, "reconnect");
-}
-
 static void proxy_watchdog(ckpool_t *ckp, server_instance_t *cursi)
 {
 	gdata_t *gdata = ckp->data;
@@ -1865,10 +1867,8 @@ int generator(proc_instance_t *pi)
 	if (ckp->proxy) {
 		gdata->srvchk = create_ckmsgq(ckp, "prxchk", &proxy_watchdog);
 		ret = proxy_mode(ckp, pi);
-	} else {
+	} else
-		gdata->srvchk = create_ckmsgq(ckp, "srvchk", &server_watchdog);
 		ret = server_mode(ckp, pi);
-	}
 
 	dealloc(ckp->data);
 	return process_exit(ckp, pi, ret);