nic_router: batch packet stream signals

genodelabs/genode#4555

repos/os/src/server/nic_router/dhcp_client.cc

@@ -228,4 +228,6 @@ void Dhcp_client::_send(Message_type msg_type,
 		ip.total_length(size_guard.head_size() - ip_off);
 		ip.update_checksum();
 	});
+
+	_interface.wakeup_source();
 }

repos/os/src/server/nic_router/interface.cc

@@ -1538,7 +1538,7 @@ void Interface::_handle_pkt_stream_signal()
 	 * sending new packets in the subsequent steps of this handler.
 	 */
 	while (_source.ack_avail()) {
-		_source.release_packet(_source.get_acked_packet());
+		_source.release_packet(_source.try_get_acked_packet());
 	}
 
 	/*
@@ -1567,6 +1567,23 @@ void Interface::_handle_pkt_stream_signal()
 			_handle_pkt();
 		}
 	}
+
+	/*
+	 * Since we use the try_*() variants of the packet-stream API, we
+	 * haven't emitted any packet_avail, ack_avail, ready_to_submit or
+	 * ready_to_ack signal up to now. We've removed packets from our sink's
+	 * submit queue and might have forwarded it to any interface. We may have
+	 * also removed acks from our sink's ack queue.
+	 *
+	 * We therefore wakeup all sources and our sink. Note that the packet-stream
+	 * API takes care of emitting only the signals that are actually needed.
+	 */
+	_config().domains().for_each([&] (Domain &domain) {
+		domain.interfaces().for_each([&] (Interface &interface) {
+			interface.wakeup_source();
+		});
+	});
+	wakeup_sink();
 }
 
 
@@ -1810,7 +1827,7 @@ void Interface::_send_submit_pkt(Packet_descriptor &pkt,
 		}
 		catch (Size_guard::Exceeded) { log("[", local_domain, "] snd ?"); }
 	}
-	_source.submit_packet(pkt);
+	_source.try_submit_packet(pkt);
 }
 
 
@@ -2132,6 +2149,13 @@ void Interface::_failed_to_send_packet_link()
 }
 
 
+void Interface::_failed_to_send_packet_submit()
+{
+	if (_config().verbose()) {
+		log("[", _domain(), "] failed to send packet (queue full)"); }
+}
+
+
 void Interface::_failed_to_send_packet_alloc()
 {
 	if (_config().verbose()) {
@@ -2254,14 +2278,13 @@ void Interface::handle_config_3()
 
 void Interface::_ack_packet(Packet_descriptor const &pkt)
 {
-	if (!_sink.ready_to_ack()) {
+	if (!_sink.try_ack_packet(pkt)) {
 		if (_config().verbose()) {
 			log("[", _domain(), "] leak packet (sink not ready to "
 			    "acknowledge)");
 		}
 		return;
 	}
-	_sink.acknowledge_packet(pkt);
 }
 
 

repos/os/src/server/nic_router/interface.h

@@ -345,6 +345,8 @@ class Net::Interface : private Interface_list::Element
 
 		void _failed_to_send_packet_link();
 
+		void _failed_to_send_packet_submit();
+
 		void _failed_to_send_packet_alloc();
 
 		void _send_icmp_dst_unreachable(Ipv4_address_prefix const &local_intf,
@@ -394,6 +396,10 @@ class Net::Interface : private Interface_list::Element
 				_failed_to_send_packet_link();
 				return;
 			}
+			if (!_source.ready_to_submit()) {
+				_failed_to_send_packet_submit();
+				return;
+			}
 			try {
 				Packet_descriptor  pkt;
 				void              *pkt_base;
@@ -456,6 +462,8 @@ class Net::Interface : private Interface_list::Element
 		Interface_link_stats      &icmp_stats()                      { return _icmp_stats; }
 		Interface_object_stats    &arp_stats()                       { return _arp_stats; }
 		Interface_object_stats    &dhcp_stats()                      { return _dhcp_stats; }
+		void                       wakeup_source()                   { _source.wakeup(); }
+		void                       wakeup_sink()                     { _sink.wakeup(); }
 };
 
 #endif /* _INTERFACE_H_ */

repos/os/src/server/nic_router/nic_client.cc

@@ -170,6 +170,12 @@ Net::Nic_client_interface::Nic_client_interface(Env                 &env,
 	rx_channel()->sigh_packet_avail(_interface.pkt_stream_signal_handler());
 	tx_channel()->sigh_ack_avail   (_interface.pkt_stream_signal_handler());
 
+	/*
+	 * We do not install ready_to_submit because submission is only triggered
+	 * by incoming packets (and dropped if the submit queue is full).
+	 * The ack queue should never be full otherwise we'll be leaking packets.
+	 */
+
 	/* initialize link state handling */
 	Nic::Connection::link_state_sigh(_session_link_state_handler);
 	_session_link_state = Nic::Connection::link_state();

repos/os/src/server/nic_router/nic_session_root.cc

@@ -256,6 +256,12 @@ Nic_session_component(Session_env                    &session_env,
 	/* install packet stream signal handlers */
 	_tx.sigh_packet_avail(_interface.pkt_stream_signal_handler());
 	_rx.sigh_ack_avail   (_interface.pkt_stream_signal_handler());
+
+	/*
+	 * We do not install ready_to_submit because submission is only triggered by
+	 * incoming packets (and dropped if the submit queue is full).
+	 * The ack queue should never be full otherwise we'll be leaking packets.
+	 */
 }
 
 

repos/os/src/server/nic_router/uplink_session_root.cc

@@ -104,6 +104,12 @@ Net::Uplink_session_component::Uplink_session_component(Session_env
 	/* install packet stream signal handlers */
 	_tx.sigh_packet_avail(_interface.pkt_stream_signal_handler());
 	_rx.sigh_ack_avail   (_interface.pkt_stream_signal_handler());
+
+	/*
+	 * We do not install ready_to_submit because submission is only triggered by
+	 * incoming packets (and dropped if the submit queue is full).
+	 * The ack queue should never be full otherwise we'll be leaking packets.
+	 */
 }