Allow adjusting priority coming from Signed Extensions

bin/node/cli/src/service.rs

@@ -817,7 +817,7 @@ mod tests {
 				let check_genesis = frame_system::CheckGenesis::new();
 				let check_era = frame_system::CheckEra::from(Era::Immortal);
 				let check_nonce = frame_system::CheckNonce::from(index);
-				let check_weight = frame_system::CheckWeight::new();
+				let check_weight = frame_system::CheckWeight::new().into();
 				let payment = pallet_transaction_payment::ChargeTransactionPayment::from(0);
 				let extra = (
 					check_spec_version,

bin/node/runtime/src/lib.rs

@@ -25,6 +25,7 @@
 use codec::{Decode, Encode, MaxEncodedLen};
 use frame_support::{
 	construct_runtime, parameter_types,
+	signed_extensions::{AdjustPriority, Divide},
 	traits::{
 		Currency, Everything, Imbalance, InstanceFilter, KeyOwnerProofSystem, LockIdentifier,
 		Nothing, OnUnbalanced, U128CurrencyToVote,
@@ -927,7 +928,7 @@ where
 			frame_system::CheckGenesis::<Runtime>::new(),
 			frame_system::CheckEra::<Runtime>::from(era),
 			frame_system::CheckNonce::<Runtime>::from(nonce),
-			frame_system::CheckWeight::<Runtime>::new(),
+			frame_system::CheckWeight::<Runtime>::new().into(),
 			pallet_transaction_payment::ChargeTransactionPayment::<Runtime>::from(tip),
 		);
 		let raw_payload = SignedPayload::new(call, extra)
@@ -1268,7 +1269,7 @@ pub type SignedExtra = (
 	frame_system::CheckGenesis<Runtime>,
 	frame_system::CheckEra<Runtime>,
 	frame_system::CheckNonce<Runtime>,
-	frame_system::CheckWeight<Runtime>,
+	AdjustPriority<frame_system::CheckWeight<Runtime>, Divide, CHECK_WEIGHT_PRIORITY_DIVISOR>,
 	pallet_transaction_payment::ChargeTransactionPayment<Runtime>,
 );
 /// Unchecked extrinsic type as expected by this runtime.
@@ -1297,6 +1298,22 @@ mod mmr {
 	pub type Hashing = <Runtime as pallet_mmr::Config>::Hashing;
 }
 
+/// There are two extensions returning the priority:
+/// 1. The `CheckWeight` extension.
+/// 2. The `TransactionPayment` extension.
+///
+/// The first one gives a significant bump to `Operational` transactions, but for `Normal`
+/// it's within `[0..MAXIMUM_BLOCK_WEIGHT]` range.
+///
+/// The second one roughly represents the amount of fees being paid (and the tip) with
+/// size-adjustment coefficient. I.e. we are interested to maximize `fee/consumed_weight` or
+/// `fee/size_limit`. The returned value is potentially unbounded though.
+///
+/// The idea for the adjustment is scale the priority coming from `CheckWeight` for
+/// `Normal` transactions down to zero, leaving the priority bump for `Operational` and
+/// `Mandatory` though.
+const CHECK_WEIGHT_PRIORITY_DIVISOR: TransactionPriority = MAXIMUM_BLOCK_WEIGHT;
+
 impl_runtime_apis! {
 	impl sp_api::Core<Block> for Runtime {
 		fn version() -> RuntimeVersion {

bin/node/test-runner-example/src/lib.rs

@@ -76,7 +76,7 @@ impl ChainInfo for NodeTemplateChainInfo {
 			frame_system::CheckNonce::<Self::Runtime>::from(
 				frame_system::Pallet::<Self::Runtime>::account_nonce(from),
 			),
-			frame_system::CheckWeight::<Self::Runtime>::new(),
+			frame_system::CheckWeight::<Self::Runtime>::new().into(),
 			pallet_transaction_payment::ChargeTransactionPayment::<Self::Runtime>::from(0),
 		)
 	}

bin/node/testing/src/keyring.rs

@@ -75,7 +75,7 @@ pub fn signed_extra(nonce: Index, extra_fee: Balance) -> SignedExtra {
 		frame_system::CheckGenesis::new(),
 		frame_system::CheckEra::from(Era::mortal(256, 0)),
 		frame_system::CheckNonce::from(nonce),
-		frame_system::CheckWeight::new(),
+		frame_system::CheckWeight::new().into(),
 		pallet_transaction_payment::ChargeTransactionPayment::from(extra_fee),
 	)
 }

frame/support/src/lib.rs

@@ -60,6 +60,7 @@ pub mod inherent;
 pub mod error;
 pub mod instances;
 pub mod migrations;
+pub mod signed_extensions;
 pub mod traits;
 pub mod weights;