[EVM] Adjust locking for replacement (#224)

Author: stevenlanders

internal/mempool/mempool.go

@@ -665,19 +665,11 @@ func (txmp *TxMempool) addNewTransaction(wtx *WrappedTx, res *abci.ResponseCheck
 		txInfo.SenderID: {},
 	}
 
-	replaced, shouldDrop := txmp.priorityIndex.TryReplacement(wtx)
-	if shouldDrop {
+	if txmp.isInMempool(wtx.tx) {
 		return nil
 	}
 
-	txmp.metrics.TxSizeBytes.Observe(float64(wtx.Size()))
-	txmp.metrics.Size.Set(float64(txmp.SizeWithoutPending()))
-	txmp.metrics.PendingSize.Set(float64(txmp.PendingSize()))
-
-	if replaced != nil {
-		txmp.removeTx(replaced, true, false, false)
-	}
-	if txmp.insertTx(wtx, replaced == nil) {
+	if txmp.insertTx(wtx) {
 		txmp.logger.Debug(
 			"inserted good transaction",
 			"priority", wtx.priority,
@@ -871,15 +863,20 @@ func (txmp *TxMempool) canAddPendingTx(wtx *WrappedTx) error {
 	return nil
 }
 
-func (txmp *TxMempool) insertTx(wtx *WrappedTx, updatePriorityIndex bool) bool {
-	if txmp.isInMempool(wtx.tx) {
+func (txmp *TxMempool) insertTx(wtx *WrappedTx) bool {
+	replacedTx, inserted := txmp.priorityIndex.PushTx(wtx)
+	if !inserted {
 		return false
 	}
+	txmp.metrics.TxSizeBytes.Observe(float64(wtx.Size()))
+	txmp.metrics.Size.Set(float64(txmp.SizeWithoutPending()))
+	txmp.metrics.PendingSize.Set(float64(txmp.PendingSize()))
 
-	txmp.txStore.SetTx(wtx)
-	if updatePriorityIndex {
-		txmp.priorityIndex.PushTx(wtx)
+	if replacedTx != nil {
+		txmp.removeTx(replacedTx, true, false, false)
 	}
+
+	txmp.txStore.SetTx(wtx)
 	txmp.heightIndex.Insert(wtx)
 	txmp.timestampIndex.Insert(wtx)
 

internal/mempool/priority_queue.go

@@ -71,12 +71,10 @@ func (pq *TxPriorityQueue) getTxWithSameNonceUnsafe(tx *WrappedTx) (*WrappedTx,
 	return nil, -1
 }
 
-func (pq *TxPriorityQueue) TryReplacement(tx *WrappedTx) (replaced *WrappedTx, shouldDrop bool) {
+func (pq *TxPriorityQueue) tryReplacementUnsafe(tx *WrappedTx) (replaced *WrappedTx, shouldDrop bool) {
 	if !tx.isEVM {
 		return nil, false
 	}
-	pq.mtx.Lock()
-	defer pq.mtx.Unlock()
 	queue, ok := pq.evmQueue[tx.evmAddress]
 	if ok && len(queue) > 0 {
 		existing, idx := pq.getTxWithSameNonceUnsafe(tx)
@@ -338,11 +336,25 @@ func (pq *TxPriorityQueue) pushTxUnsafe(tx *WrappedTx) {
 //}
 
 // PushTx adds a valid transaction to the priority queue. It is thread safe.
-func (pq *TxPriorityQueue) PushTx(tx *WrappedTx) {
+func (pq *TxPriorityQueue) PushTx(tx *WrappedTx) (*WrappedTx, bool) {
 	pq.mtx.Lock()
 	defer pq.mtx.Unlock()
 
+	replacedTx, shouldDrop := pq.tryReplacementUnsafe(tx)
+
+	// tx was not inserted, and nothing was replaced
+	if shouldDrop {
+		return nil, false
+	}
+
+	// tx replaced an existing transaction
+	if replacedTx != nil {
+		return replacedTx, true
+	}
+
+	// tx was not inserted yet, so insert it
 	pq.pushTxUnsafe(tx)
+	return nil, true
 }
 
 func (pq *TxPriorityQueue) popTxUnsafe() *WrappedTx {

internal/mempool/priority_queue_test.go

@@ -70,7 +70,7 @@ func TestTxPriorityQueue_PriorityAndNonceOrdering(t *testing.T) {
 				{sender: "3", isEVM: true, evmAddress: "0xabc", evmNonce: 3, priority: 9},
 				{sender: "2", isEVM: true, evmAddress: "0xabc", evmNonce: 1, priority: 7},
 			},
-			expectedOutput: []int64{1, 2, 3},
+			expectedOutput: []int64{1, 3},
 		},
 		{
 			name: "PriorityWithEVMAndNonEVMDuplicateNonce",
@@ -380,17 +380,23 @@ func TestTxPriorityQueue_TryReplacement(t *testing.T) {
 		expectedQueue    []*WrappedTx
 		expectedHeap     []*WrappedTx
 	}{
-		{&WrappedTx{isEVM: false}, []*WrappedTx{}, false, false, []*WrappedTx{}, []*WrappedTx{}},
-		{&WrappedTx{isEVM: true, evmAddress: "addr1"}, []*WrappedTx{}, false, false, []*WrappedTx{}, []*WrappedTx{}},
+		// non-evm transaction is inserted into empty queue
+		{&WrappedTx{isEVM: false}, []*WrappedTx{}, false, false, []*WrappedTx{{isEVM: false}}, []*WrappedTx{{isEVM: false}}},
+		// evm transaction is inserted into empty queue
+		{&WrappedTx{isEVM: true, evmAddress: "addr1"}, []*WrappedTx{}, false, false, []*WrappedTx{{isEVM: true, evmAddress: "addr1"}}, []*WrappedTx{{isEVM: true, evmAddress: "addr1"}}},
+		// evm transaction (new nonce) is inserted into queue with existing tx (lower nonce)
 		{
 			&WrappedTx{isEVM: true, evmAddress: "addr1", evmNonce: 1, priority: 100, tx: []byte("abc")}, []*WrappedTx{
 				{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("def")},
 			}, false, false, []*WrappedTx{
 				{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("def")},
+				{isEVM: true, evmAddress: "addr1", evmNonce: 1, priority: 100, tx: []byte("abc")},
 			}, []*WrappedTx{
 				{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("def")},
+				{isEVM: true, evmAddress: "addr1", evmNonce: 1, priority: 100, tx: []byte("abc")},
 			},
 		},
+		// evm transaction (new nonce) is not inserted because it's a duplicate nonce and same priority
 		{
 			&WrappedTx{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("abc")}, []*WrappedTx{
 				{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("def")},
@@ -400,6 +406,7 @@ func TestTxPriorityQueue_TryReplacement(t *testing.T) {
 				{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("def")},
 			},
 		},
+		// evm transaction (new nonce) replaces the existing nonce transaction because its priority is higher
 		{
 			&WrappedTx{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 101, tx: []byte("abc")}, []*WrappedTx{
 				{isEVM: true, evmAddress: "addr1", evmNonce: 0, priority: 100, tx: []byte("def")},
@@ -425,13 +432,13 @@ func TestTxPriorityQueue_TryReplacement(t *testing.T) {
 		for _, e := range test.existing {
 			pq.PushTx(e)
 		}
-		replaced, dropped := pq.TryReplacement(test.tx)
+		replaced, inserted := pq.PushTx(test.tx)
 		if test.expectedReplaced {
 			require.NotNil(t, replaced)
 		} else {
 			require.Nil(t, replaced)
 		}
-		require.Equal(t, test.expectedDropped, dropped)
+		require.Equal(t, test.expectedDropped, !inserted)
 		for i, q := range pq.evmQueue[test.tx.evmAddress] {
 			require.Equal(t, test.expectedQueue[i].tx.Key(), q.tx.Key())
 			require.Equal(t, test.expectedQueue[i].priority, q.priority)

internal/mempool/reactor_test.go

@@ -167,7 +167,7 @@ func TestReactorBroadcastDoesNotPanic(t *testing.T) {
 	secondaryReactor.observePanic = observePanic
 
 	firstTx := &WrappedTx{}
-	primaryMempool.insertTx(firstTx, true)
+	primaryMempool.insertTx(firstTx)
 
 	// run the router
 	rts.start(ctx, t)
@@ -180,7 +180,7 @@ func TestReactorBroadcastDoesNotPanic(t *testing.T) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			primaryMempool.insertTx(next, true)
+			primaryMempool.insertTx(next)
 		}()
 	}