polkadot: eradicate LeafStatus (#1565)

Fixes #768.

polkadot/node/overseer/src/dummy.rs

@@ -17,11 +17,9 @@
 use crate::{
 	prometheus::Registry, HeadSupportsParachains, InitializedOverseerBuilder, MetricsTrait,
 	Overseer, OverseerMetrics, OverseerSignal, OverseerSubsystemContext, SpawnGlue,
-	KNOWN_LEAVES_CACHE_SIZE,
 };
 use orchestra::{FromOrchestra, SpawnedSubsystem, Subsystem, SubsystemContext};
 use polkadot_node_subsystem_types::{errors::SubsystemError, messages::*};
-use schnellru::{ByLength, LruMap};
 // Generated dummy messages
 use crate::messages::*;
 
@@ -193,7 +191,6 @@ where
 		.activation_external_listeners(Default::default())
 		.span_per_active_leaf(Default::default())
 		.active_leaves(Default::default())
-		.known_leaves(LruMap::new(ByLength::new(KNOWN_LEAVES_CACHE_SIZE)))
 		.spawner(SpawnGlue(spawner))
 		.metrics(metrics)
 		.supports_parachains(supports_parachains);

polkadot/node/overseer/src/lib.rs

@@ -70,7 +70,6 @@ use std::{
 };
 
 use futures::{channel::oneshot, future::BoxFuture, select, Future, FutureExt, StreamExt};
-use schnellru::LruMap;
 
 use client::{BlockImportNotification, BlockchainEvents, FinalityNotification};
 use polkadot_primitives::{Block, BlockNumber, Hash};
@@ -88,8 +87,8 @@ use polkadot_node_subsystem_types::messages::{
 
 pub use polkadot_node_subsystem_types::{
 	errors::{SubsystemError, SubsystemResult},
-	jaeger, ActivatedLeaf, ActiveLeavesUpdate, LeafStatus, OverseerSignal,
-	RuntimeApiSubsystemClient, UnpinHandle,
+	jaeger, ActivatedLeaf, ActiveLeavesUpdate, OverseerSignal, RuntimeApiSubsystemClient,
+	UnpinHandle,
 };
 
 pub mod metrics;
@@ -112,10 +111,6 @@ pub use orchestra::{
 	SubsystemSender, TimeoutExt, ToOrchestra, TrySendError,
 };
 
-/// Store 2 days worth of blocks, not accounting for forks,
-/// in the LRU cache. Assumes a 6-second block time.
-pub const KNOWN_LEAVES_CACHE_SIZE: u32 = 2 * 24 * 3600 / 6;
-
 #[cfg(any(target_os = "linux", feature = "jemalloc-allocator"))]
 mod memory_stats;
 #[cfg(test)]
@@ -283,6 +278,11 @@ impl From<FinalityNotification<Block>> for BlockInfo {
 /// as the substrate framework or user interaction.
 pub enum Event {
 	/// A new block was imported.
+	///
+	/// This event is not sent if the block was already known
+	/// and we reorged to it e.g. due to a reversion.
+	///
+	/// Also, these events are not sent during a major sync.
 	BlockImported(BlockInfo),
 	/// A block was finalized with i.e. babe or another consensus algorithm.
 	BlockFinalized(BlockInfo),
@@ -641,9 +641,6 @@ pub struct Overseer<SupportsParachains> {
 	/// An implementation for checking whether a header supports parachain consensus.
 	pub supports_parachains: SupportsParachains,
 
-	/// An LRU cache for keeping track of relay-chain heads that have already been seen.
-	pub known_leaves: LruMap<Hash, ()>,
-
 	/// Various Prometheus metrics.
 	pub metrics: OverseerMetrics,
 }
@@ -802,10 +799,9 @@ where
 		};
 
 		let mut update = match self.on_head_activated(&block.hash, Some(block.parent_hash)).await {
-			Some((span, status)) => ActiveLeavesUpdate::start_work(ActivatedLeaf {
+			Some(span) => ActiveLeavesUpdate::start_work(ActivatedLeaf {
 				hash: block.hash,
 				number: block.number,
-				status,
 				unpin_handle: block.unpin_handle,
 				span,
 			}),
@@ -864,7 +860,7 @@ where
 		&mut self,
 		hash: &Hash,
 		parent_hash: Option<Hash>,
-	) -> Option<(Arc<jaeger::Span>, LeafStatus)> {
+	) -> Option<Arc<jaeger::Span>> {
 		if !self.supports_parachains.head_supports_parachains(hash).await {
 			return None
 		}
@@ -891,14 +887,7 @@ where
 		let span = Arc::new(span);
 		self.span_per_active_leaf.insert(*hash, span.clone());
 
-		let status = if self.known_leaves.get(hash).is_some() {
-			LeafStatus::Stale
-		} else {
-			self.known_leaves.insert(*hash, ());
-			LeafStatus::Fresh
-		};
-
-		Some((span, status))
+		Some(span)
 	}
 
 	fn on_head_deactivated(&mut self, hash: &Hash) {