Use CLI to configure max instances cache (#5177)

* Use CLI to configure max instances cache

* Fix tests

* Move default value into CLI

* Use SmallVec

* Apply review comments

* Get rid of `SmallVec`

Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/client/service/src/builder.rs

@@ -226,6 +226,7 @@ fn new_full_parts<TBl, TRtApi, TExecDisp, TGen, TCSExt>(
 	let executor = NativeExecutor::<TExecDisp>::new(
 		config.wasm_method,
 		config.default_heap_pages,
+		config.max_runtime_instances,
 	);
 
 	let chain_spec = config.expect_chain_spec();
@@ -352,6 +353,7 @@ where TGen: RuntimeGenesis, TCSExt: Extension {
 		let executor = NativeExecutor::<TExecDisp>::new(
 			config.wasm_method,
 			config.default_heap_pages,
+			config.max_runtime_instances,
 		);
 
 		let db_storage = {

substrate/client/service/src/config.rs

@@ -123,6 +123,10 @@ pub struct Configuration<G, E = NoExtension> {
 	pub tracing_targets: Option<String>,
 	/// Tracing receiver
 	pub tracing_receiver: sc_tracing::TracingReceiver,
+	/// The size of the instances cache.
+	///
+	/// The default value is 8.
+	pub max_runtime_instances: usize,
 }
 
 /// Configuration of the client keystore.
@@ -224,6 +228,7 @@ impl<G, E> Default for Configuration<G, E> {
 			dev_key_seed: None,
 			tracing_targets: Default::default(),
 			tracing_receiver: Default::default(),
+			max_runtime_instances: 8,
 		}
 	}
 }