LRU process proposal cache

crates/node/src/lib.rs

@@ -151,7 +151,7 @@ impl Shell {
                     self.state
                         .in_mem_mut()
                         .process_proposal_cache
-                        .insert(block_hash, result);
+                        .put(block_hash, result);
                 }
                 Ok(Response::ProcessProposal(response))
             }
@@ -218,7 +218,7 @@ impl Shell {
         if recheck_process_proposal {
             let process_proposal_result = match self
                 .state
-                .in_mem()
+                .in_mem_mut()
                 .process_proposal_cache
                 .get(&finalize_req.block_hash)
             {

crates/node/src/shims/abcipp_shim.rs

@@ -183,7 +183,7 @@ impl AbcippShim {
                 match self
                     .service
                     .state
-                    .in_mem()
+                    .in_mem_mut()
                     .process_proposal_cache
                     .get(&block_hash)
                 {
@@ -216,7 +216,7 @@ impl AbcippShim {
                             .state
                             .in_mem_mut()
                             .process_proposal_cache
-                            .insert(block_hash.to_owned(), result.clone());
+                            .put(block_hash.to_owned(), result.clone());
 
                         result
                     }

crates/state/Cargo.toml

@@ -40,6 +40,7 @@ namada_storage = { path = "../storage" }
 namada_tx = { path = "../tx" }
 
 borsh.workspace = true
+clru.workspace = true
 itertools.workspace = true
 linkme = {workspace = true, optional = true}
 smooth-operator.workspace = true

crates/state/src/in_memory.rs

@@ -1,3 +1,6 @@
+use std::num::NonZeroUsize;
+
+use clru::CLruCache;
 use namada_core::address::{Address, EstablishedAddressGen, InternalAddress};
 use namada_core::borsh::{BorshDeserialize, BorshSerialize};
 use namada_core::chain::{ChainId, CHAIN_ID_LENGTH};
@@ -74,13 +77,13 @@ where
     /// Data that needs to be committed to the merkle tree
     pub commit_only_data: CommitOnlyData,
     /// Cache of the results of process proposal for the next height to decide.
-    /// The different proposed blocks are indexed by their hash. This is used
+    /// A LRU cache is used to prevent consuming too much memory at times where
+    /// a node cannot make progress and keeps evaluating new proposals. The
+    /// different proposed blocks are indexed by their hash. This is used
     /// to avoid running process proposal more than once internally because of
     /// the shim or the recheck option (comet only calls it at most once
     /// for a given height/round)
-    // FIXME: would be better to limit the size of this cache. CLruCache?
-    pub process_proposal_cache:
-        namada_core::collections::HashMap<Hash, ProcessProposalCachedResult>,
+    pub process_proposal_cache: CLruCache<Hash, ProcessProposalCachedResult>,
 }
 
 /// Last committed block
@@ -162,7 +165,9 @@ where
             eth_events_queue: EthEventsQueue::default(),
             storage_read_past_height_limit,
             commit_only_data: CommitOnlyData::default(),
-            process_proposal_cache: Default::default(),
+            process_proposal_cache: CLruCache::new(
+                NonZeroUsize::new(10).unwrap(),
+            ),
         }
     }
 

crates/state/src/lib.rs

@@ -595,6 +595,9 @@ where
 #[cfg(any(test, feature = "testing"))]
 pub mod testing {
 
+    use std::num::NonZeroUsize;
+
+    use clru::CLruCache;
     use namada_core::address;
     use namada_core::address::EstablishedAddressGen;
     use namada_core::chain::ChainId;
@@ -658,7 +661,9 @@ pub mod testing {
                 eth_events_queue: EthEventsQueue::default(),
                 storage_read_past_height_limit: Some(1000),
                 commit_only_data: CommitOnlyData::default(),
-                process_proposal_cache: Default::default(),
+                process_proposal_cache: CLruCache::new(
+                    NonZeroUsize::new(10).unwrap(),
+                ),
             }
         }
     }