litep2p: Periodically perform kademlia queries instead if under number

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

substrate/client/network/src/litep2p/discovery.rs

@@ -51,7 +51,7 @@ use std::{
 	cmp,
 	collections::{HashMap, HashSet, VecDeque},
 	pin::Pin,
-	sync::{atomic::AtomicUsize, Arc},
+	sync::Arc,
 	task::{Context, Poll},
 	time::{Duration, Instant},
 };
@@ -204,12 +204,6 @@ pub struct Discovery {
 
 	/// Delay to next `FIND_NODE` query.
 	duration_to_next_find_query: Duration,
-
-	/// Number of connected peers as reported by the blocks announcement protocol.
-	num_connected_peers: Arc<AtomicUsize>,
-
-	/// Number of active connections over which we interrupt the discovery process.
-	discovery_only_if_under_num: usize,
 }
 
 /// Legacy (fallback) Kademlia protocol name based on `protocol_id`.
@@ -244,8 +238,6 @@ impl Discovery {
 		protocol_id: &ProtocolId,
 		known_peers: HashMap<PeerId, Vec<Multiaddr>>,
 		listen_addresses: Arc<RwLock<HashSet<Multiaddr>>>,
-		num_connected_peers: Arc<AtomicUsize>,
-		discovery_only_if_under_num: usize,
 		_peerstore_handle: Arc<dyn PeerStoreProvider>,
 	) -> (Self, PingConfig, IdentifyConfig, KademliaConfig, Option<MdnsConfig>) {
 		let (ping_config, ping_event_stream) = PingConfig::default();
@@ -299,8 +291,6 @@ impl Discovery {
 					genesis_hash,
 					fork_id,
 				)]),
-				num_connected_peers,
-				discovery_only_if_under_num,
 			},
 			ping_config,
 			identify_config,
@@ -309,11 +299,6 @@ impl Discovery {
 		)
 	}
 
-	/// Get number of connected peers.
-	fn num_connected_peers(&self) -> usize {
-		self.num_connected_peers.load(std::sync::atomic::Ordering::Relaxed)
-	}
-
 	/// Add known peer to `Kademlia`.
 	#[allow(unused)]
 	pub async fn add_known_peer(&mut self, peer: PeerId, addresses: Vec<Multiaddr>) {
@@ -473,10 +458,7 @@ impl Stream for Discovery {
 		if let Some(mut delay) = this.next_kad_query.take() {
 			match delay.poll_unpin(cx) {
 				Poll::Ready(()) => {
-					let num_peers = this.num_connected_peers();
-					if num_peers < this.discovery_only_if_under_num &&
-						this.find_node_queries.len() < MAX_INFLIGHT_FIND_NODE_QUERIES
-					{
+					if this.find_node_queries.len() < MAX_INFLIGHT_FIND_NODE_QUERIES {
 						let peer = PeerId::random();
 						log::debug!(target: LOG_TARGET, "start next kademlia query for {peer:?}");
 
@@ -495,9 +477,7 @@ impl Stream for Discovery {
 					} else {
 						log::debug!(
 							target: LOG_TARGET,
-							"discovery is paused: {num_peers}/{} connected peers and in flight queries: {}/{MAX_INFLIGHT_FIND_NODE_QUERIES}",
-							this.discovery_only_if_under_num,
-							this.find_node_queries.len(),
+							"discovery is paused; too many in-flight queries",
 						);
 					}
 

substrate/client/network/src/litep2p/mod.rs

@@ -88,10 +88,7 @@ use std::{
 	future::Future,
 	iter,
 	pin::Pin,
-	sync::{
-		atomic::{AtomicUsize, Ordering},
-		Arc,
-	},
+	sync::{atomic::Ordering, Arc},
 	time::{Duration, Instant},
 };
 
@@ -166,11 +163,6 @@ pub struct Litep2pNetworkBackend {
 	/// Discovery.
 	discovery: Discovery,
 
-	/// Number of uniquely connected peers.
-	///
-	/// This is used to instruct the discovery about the number of connected peers.
-	num_uniquely_connected: Arc<AtomicUsize>,
-
 	/// Connected peers.
 	peers: HashMap<litep2p::PeerId, ConnectionContext>,
 
@@ -441,9 +433,6 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkBackend<B, H> for Litep2pNetworkBac
 		let peer_store_handle = params.network_config.peer_store_handle();
 		let executor = Arc::new(Litep2pExecutor { executor: params.executor });
 
-		let limit_discovery_under =
-			params.network_config.network_config.default_peers_set.out_peers as usize + 15;
-
 		let FullNetworkConfiguration {
 			notification_protocols,
 			request_response_protocols,
@@ -547,7 +536,6 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkBackend<B, H> for Litep2pNetworkBac
 
 		// enable ipfs ping, identify and kademlia, and potentially mdns if user enabled it
 		let listen_addresses = Arc::new(Default::default());
-		let num_uniquely_connected = Arc::new(Default::default());
 
 		let (discovery, ping_config, identify_config, kademlia_config, maybe_mdns_config) =
 			Discovery::new(
@@ -557,8 +545,6 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkBackend<B, H> for Litep2pNetworkBac
 				&params.protocol_id,
 				known_addresses.clone(),
 				Arc::clone(&listen_addresses),
-				Arc::clone(&num_uniquely_connected),
-				limit_discovery_under,
 				Arc::clone(&peer_store_handle),
 			);
 
@@ -614,7 +600,6 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkBackend<B, H> for Litep2pNetworkBac
 			cmd_rx,
 			metrics,
 			peerset_handles: notif_protocols,
-			num_uniquely_connected,
 			discovery,
 			pending_put_values: HashMap::new(),
 			pending_get_values: HashMap::new(),
@@ -691,8 +676,6 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkBackend<B, H> for Litep2pNetworkBac
 		log::debug!(target: LOG_TARGET, "starting litep2p network backend");
 
 		loop {
-			self.num_uniquely_connected.store(self.peers.len(), Ordering::Relaxed);
-
 			tokio::select! {
 				command = self.cmd_rx.next() => match command {
 					None => return,