Maximum extrinsic weight limit (#6067)

* Only check single extrinsics weight limit in validate_transaction.

* Add missing parameter to all pallets.

* Add tests, fix default configuration.

* Bump spec version.

* Use AvailableBlockRation to calculate MaxExtrinsicWeight

substrate/bin/node-template/runtime/src/lib.rs

@@ -16,6 +16,7 @@ use sp_runtime::{
 };
 use sp_runtime::traits::{
 	BlakeTwo256, Block as BlockT, IdentityLookup, Verify, ConvertInto, IdentifyAccount, NumberFor,
+	Saturating,
 };
 use sp_api::impl_runtime_apis;
 use sp_consensus_aura::sr25519::AuthorityId as AuraId;
@@ -127,6 +128,9 @@ parameter_types! {
 	/// We allow for 2 seconds of compute with a 6 second average block time.
 	pub const MaximumBlockWeight: Weight = 2 * WEIGHT_PER_SECOND;
 	pub const AvailableBlockRatio: Perbill = Perbill::from_percent(75);
+	/// Assume 10% of weight for average on_initialize calls.
+	pub const MaximumExtrinsicWeight: Weight = AvailableBlockRatio::get()
+		.saturating_sub(Perbill::from_percent(10)) * MaximumBlockWeight::get();
 	pub const MaximumBlockLength: u32 = 5 * 1024 * 1024;
 	pub const Version: RuntimeVersion = VERSION;
 }
@@ -164,6 +168,10 @@ impl system::Trait for Runtime {
 	/// The base weight of any extrinsic processed by the runtime, independent of the
 	/// logic of that extrinsic. (Signature verification, nonce increment, fee, etc...)
 	type ExtrinsicBaseWeight = ExtrinsicBaseWeight;
+	/// The maximum weight that a single extrinsic of `Normal` dispatch class can have,
+	/// idependent of the logic of that extrinsics. (Roughly max block weight - average on
+	/// initialize cost).
+	type MaximumExtrinsicWeight = MaximumExtrinsicWeight;
 	/// Maximum size of all encoded transactions (in bytes) that are allowed in one block.
 	type MaximumBlockLength = MaximumBlockLength;
 	/// Portion of the block weight that is available to all normal transactions.