v1.18: Disable cache warmer if RPC is not using it (backport of #1063) (#1068)

Disable connection cache warmer for tpu if no rpc services using it.

(cherry picked from commit d87e23d)

# Conflicts:
#	core/src/tvu.rs

* Merge conflicts

---------

Co-authored-by: Lijun Wang <[email protected]>

Author: 2 people

core/src/tvu.rs

@@ -135,7 +135,7 @@ impl Tvu {
         wait_to_vote_slot: Option<Slot>,
         accounts_background_request_sender: AbsRequestSender,
         log_messages_bytes_limit: Option<usize>,
-        connection_cache: &Arc<ConnectionCache>,
+        connection_cache: Option<&Arc<ConnectionCache>>,
         prioritization_fee_cache: &Arc<PrioritizationFeeCache>,
         banking_tracer: Arc<BankingTracer>,
         turbine_quic_endpoint_sender: AsyncSender<(SocketAddr, Bytes)>,
@@ -276,16 +276,19 @@ impl Tvu {
             tower_storage,
         );
 
-        let warm_quic_cache_service = if connection_cache.use_quic() {
-            Some(WarmQuicCacheService::new(
-                connection_cache.clone(),
-                cluster_info.clone(),
-                poh_recorder.clone(),
-                exit.clone(),
-            ))
-        } else {
-            None
-        };
+        let warm_quic_cache_service = connection_cache.and_then(|connection_cache| {
+            if connection_cache.use_quic() {
+                Some(WarmQuicCacheService::new(
+                    connection_cache.clone(),
+                    cluster_info.clone(),
+                    poh_recorder.clone(),
+                    exit.clone(),
+                ))
+            } else {
+                None
+            }
+        });
+
         let (cost_update_sender, cost_update_receiver) = unbounded();
         let cost_update_service = CostUpdateService::new(blockstore.clone(), cost_update_receiver);
 
@@ -498,7 +501,7 @@ pub mod tests {
             None,
             AbsRequestSender::default(),
             None,
-            &Arc::new(ConnectionCache::new("connection_cache_test")),
+            Some(&Arc::new(ConnectionCache::new("connection_cache_test"))),
             &ignored_prioritization_fee_cache,
             BankingTracer::new_disabled(),
             turbine_quic_endpoint_sender,

core/src/validator.rs

@@ -1306,7 +1306,7 @@ impl Validator {
             config.wait_to_vote_slot,
             accounts_background_request_sender,
             config.runtime_config.log_messages_bytes_limit,
-            &connection_cache,
+            json_rpc_service.is_some().then_some(&connection_cache), // for the cache warmer only used for STS for RPC service
             &prioritization_fee_cache,
             banking_tracer.clone(),
             turbine_quic_endpoint_sender.clone(),