stasis: Add setting subscription congestion levels.

Stasis subscriptions and message routers create taskprocessors to process
the event messages.  API calls are needed to be able to set the congestion
levels of these taskprocessors for selected subscriptions and message
routers.

* Updated CDR, CEL, and manager's stasis subscription congestion levels
based upon stress testing.  Increased the congestion levels to reduce the
potential for bursty call setup/teardown activity from triggering the
taskprocessor overload alert.  CDRs in particular need an extra high
congestion level because they can take awhile to process the stasis
messages.

ASTERISK-26088
Reported by:  Richard Mudgett

Change-Id: Id0a716394b4eee746dd158acc63d703902450244

include/asterisk/stasis.h

@@ -592,6 +592,20 @@ struct stasis_subscription *stasis_subscribe_pool(struct stasis_topic *topic,
 struct stasis_subscription *stasis_unsubscribe(
 	struct stasis_subscription *subscription);
 
+/*!
+ * \brief Set the high and low alert water marks of the stasis subscription.
+ * \since 13.10.0
+ *
+ * \param subscription Pointer to a stasis subscription
+ * \param low_water New queue low water mark. (-1 to set as 90% of high_water)
+ * \param high_water New queue high water mark.
+ *
+ * \retval 0 on success.
+ * \retval -1 on error (water marks not changed).
+ */
+int stasis_subscription_set_congestion_limits(struct stasis_subscription *subscription,
+	long low_water, long high_water);
+
 /*!
  * \brief Block until the last message is processed on a subscription.
  *

include/asterisk/stasis_message_router.h

@@ -126,6 +126,20 @@ int stasis_message_router_is_done(struct stasis_message_router *router);
 void stasis_message_router_publish_sync(struct stasis_message_router *router,
 	struct stasis_message *message);
 
+/*!
+ * \brief Set the high and low alert water marks of the stasis message router.
+ * \since 13.10.0
+ *
+ * \param router Pointer to a stasis message router
+ * \param low_water New queue low water mark. (-1 to set as 90% of high_water)
+ * \param high_water New queue high water mark.
+ *
+ * \retval 0 on success.
+ * \retval -1 on error (water marks not changed).
+ */
+int stasis_message_router_set_congestion_limits(struct stasis_message_router *router,
+	long low_water, long high_water);
+
 /*!
  * \brief Add a route to a message router.
  *

main/cdr.c

@@ -71,6 +71,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/stasis_bridges.h"
 #include "asterisk/stasis_message_router.h"
 #include "asterisk/astobj2.h"
+#include "asterisk/taskprocessor.h"
 
 /*** DOCUMENTATION
 	<configInfo name="cdr" language="en_US">
@@ -4184,6 +4185,8 @@ int ast_cdr_engine_init(void)
 	if (!stasis_router) {
 		return -1;
 	}
+	stasis_message_router_set_congestion_limits(stasis_router, -1,
+		10 * AST_TASKPROCESSOR_HIGH_WATER_LEVEL);
 
 	if (STASIS_MESSAGE_TYPE_INIT(cdr_sync_message_type)) {
 		return -1;

main/cel.c

@@ -59,6 +59,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/parking.h"
 #include "asterisk/pickup.h"
 #include "asterisk/core_local.h"
+#include "asterisk/taskprocessor.h"
 
 /*** DOCUMENTATION
 	<configInfo name="cel" language="en_US">
@@ -1575,6 +1576,8 @@ static int create_routes(void)
 	if (!cel_state_router) {
 		return -1;
 	}
+	stasis_message_router_set_congestion_limits(cel_state_router, -1,
+		6 * AST_TASKPROCESSOR_HIGH_WATER_LEVEL);
 
 	ret |= stasis_message_router_add(cel_state_router,
 		stasis_cache_update_type(),

main/manager.c

@@ -100,6 +100,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/rtp_engine.h"
 #include "asterisk/format_cache.h"
 #include "asterisk/translate.h"
+#include "asterisk/taskprocessor.h"
 
 /*** DOCUMENTATION
 	<manager name="Ping" language="en_US">
@@ -8538,6 +8539,8 @@ static int manager_subscriptions_init(void)
 	if (!stasis_router) {
 		return -1;
 	}
+	stasis_message_router_set_congestion_limits(stasis_router, -1,
+		6 * AST_TASKPROCESSOR_HIGH_WATER_LEVEL);
 
 	res |= stasis_message_router_set_default(stasis_router,
 		manager_default_msg_cb, NULL);

main/stasis.c

@@ -564,6 +564,18 @@ struct stasis_subscription *stasis_unsubscribe(struct stasis_subscription *sub)
 	return NULL;
 }
 
+int stasis_subscription_set_congestion_limits(struct stasis_subscription *subscription,
+	long low_water, long high_water)
+{
+	int res = -1;
+
+	if (subscription) {
+		res = ast_taskprocessor_alert_set_levels(subscription->mailbox,
+			low_water, high_water);
+	}
+	return res;
+}
+
 void stasis_subscription_join(struct stasis_subscription *subscription)
 {
 	if (subscription) {

main/stasis_message_router.c

@@ -289,6 +289,18 @@ void stasis_message_router_publish_sync(struct stasis_message_router *router,
 	ao2_cleanup(router);
 }
 
+int stasis_message_router_set_congestion_limits(struct stasis_message_router *router,
+	long low_water, long high_water)
+{
+	int res = -1;
+
+	if (router) {
+		res = stasis_subscription_set_congestion_limits(router->subscription,
+			low_water, high_water);
+	}
+	return res;
+}
+
 int stasis_message_router_add(struct stasis_message_router *router,
 	struct stasis_message_type *message_type,
 	stasis_subscription_cb callback, void *data)