all: refactor txpool into it's own package in prep for 4844

core/txpool/journal.go

@@ -0,0 +1,181 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package txpool
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"os"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+// errNoActiveJournal is returned if a transaction is attempted to be inserted
+// into the journal, but no such file is currently open.
+var errNoActiveJournal = errors.New("no active journal")
+
+// devNull is a WriteCloser that just discards anything written into it. Its
+// goal is to allow the transaction journal to write into a fake journal when
+// loading transactions on startup without printing warnings due to no file
+// being read for write.
+type devNull struct{}
+
+func (*devNull) Write(p []byte) (n int, err error) { return len(p), nil }
+func (*devNull) Close() error                      { return nil }
+
+// journal is a rotating log of transactions with the aim of storing locally
+// created transactions to allow non-executed ones to survive node restarts.
+type journal struct {
+	path   string         // Filesystem path to store the transactions at
+	writer io.WriteCloser // Output stream to write new transactions into
+}
+
+// newTxJournal creates a new transaction journal to
+func newTxJournal(path string) *journal {
+	return &journal{
+		path: path,
+	}
+}
+
+// load parses a transaction journal dump from disk, loading its contents into
+// the specified pool.
+func (journal *journal) load(add func([]*types.Transaction) []error) error {
+	// Open the journal for loading any past transactions
+	input, err := os.Open(journal.path)
+	if errors.Is(err, fs.ErrNotExist) {
+		// Skip the parsing if the journal file doesn't exist at all
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	defer input.Close()
+
+	// Temporarily discard any journal additions (don't double add on load)
+	journal.writer = new(devNull)
+	defer func() { journal.writer = nil }()
+
+	// Inject all transactions from the journal into the pool
+	stream := rlp.NewStream(input, 0)
+	total, dropped := 0, 0
+
+	// Create a method to load a limited batch of transactions and bump the
+	// appropriate progress counters. Then use this method to load all the
+	// journaled transactions in small-ish batches.
+	loadBatch := func(txs types.Transactions) {
+		for _, err := range add(txs) {
+			if err != nil {
+				log.Debug("Failed to add journaled transaction", "err", err)
+				dropped++
+			}
+		}
+	}
+	var (
+		failure error
+		batch   types.Transactions
+	)
+	for {
+		// Parse the next transaction and terminate on error
+		tx := new(types.Transaction)
+		if err = stream.Decode(tx); err != nil {
+			if err != io.EOF {
+				failure = err
+			}
+			if batch.Len() > 0 {
+				loadBatch(batch)
+			}
+			break
+		}
+		// New transaction parsed, queue up for later, import if threshold is reached
+		total++
+
+		if batch = append(batch, tx); batch.Len() > 1024 {
+			loadBatch(batch)
+			batch = batch[:0]
+		}
+	}
+	log.Info("Loaded local transaction journal", "transactions", total, "dropped", dropped)
+
+	return failure
+}
+
+// insert adds the specified transaction to the local disk journal.
+func (journal *journal) insert(tx *types.Transaction) error {
+	if journal.writer == nil {
+		return errNoActiveJournal
+	}
+	if err := rlp.Encode(journal.writer, tx); err != nil {
+		return err
+	}
+	return nil
+}
+
+// rotate regenerates the transaction journal based on the current contents of
+// the transaction pool.
+func (journal *journal) rotate(all map[common.Address]types.Transactions) error {
+	// Close the current journal (if any is open)
+	if journal.writer != nil {
+		if err := journal.writer.Close(); err != nil {
+			return err
+		}
+		journal.writer = nil
+	}
+	// Generate a new journal with the contents of the current pool
+	replacement, err := os.OpenFile(journal.path+".new", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	journaled := 0
+	for _, txs := range all {
+		for _, tx := range txs {
+			if err = rlp.Encode(replacement, tx); err != nil {
+				replacement.Close()
+				return err
+			}
+		}
+		journaled += len(txs)
+	}
+	replacement.Close()
+
+	// Replace the live journal with the newly generated one
+	if err = os.Rename(journal.path+".new", journal.path); err != nil {
+		return err
+	}
+	sink, err := os.OpenFile(journal.path, os.O_WRONLY|os.O_APPEND, 0644)
+	if err != nil {
+		return err
+	}
+	journal.writer = sink
+	log.Info("Regenerated local transaction journal", "transactions", journaled, "accounts", len(all))
+
+	return nil
+}
+
+// close flushes the transaction journal contents to disk and closes the file.
+func (journal *journal) close() error {
+	var err error
+
+	if journal.writer != nil {
+		err = journal.writer.Close()
+		journal.writer = nil
+	}
+	return err
+}

core/txpool/list.go

@@ -0,0 +1,635 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package txpool
+
+import (
+	"container/heap"
+	"math"
+	"math/big"
+	"sort"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+// nonceHeap is a heap.Interface implementation over 64bit unsigned integers for
+// retrieving sorted transactions from the possibly gapped future queue.
+type nonceHeap []uint64
+
+func (h nonceHeap) Len() int           { return len(h) }
+func (h nonceHeap) Less(i, j int) bool { return h[i] < h[j] }
+func (h nonceHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+
+func (h *nonceHeap) Push(x interface{}) {
+	*h = append(*h, x.(uint64))
+}
+
+func (h *nonceHeap) Pop() interface{} {
+	old := *h
+	n := len(old)
+	x := old[n-1]
+	*h = old[0 : n-1]
+	return x
+}
+
+// sortedMap is a nonce->transaction hash map with a heap based index to allow
+// iterating over the contents in a nonce-incrementing way.
+type sortedMap struct {
+	items map[uint64]*types.Transaction // Hash map storing the transaction data
+	index *nonceHeap                    // Heap of nonces of all the stored transactions (non-strict mode)
+	cache types.Transactions            // Cache of the transactions already sorted
+}
+
+// newSortedMap creates a new nonce-sorted transaction map.
+func newSortedMap() *sortedMap {
+	return &sortedMap{
+		items: make(map[uint64]*types.Transaction),
+		index: new(nonceHeap),
+	}
+}
+
+// Get retrieves the current transactions associated with the given nonce.
+func (m *sortedMap) Get(nonce uint64) *types.Transaction {
+	return m.items[nonce]
+}
+
+// Put inserts a new transaction into the map, also updating the map's nonce
+// index. If a transaction already exists with the same nonce, it's overwritten.
+func (m *sortedMap) Put(tx *types.Transaction) {
+	nonce := tx.Nonce()
+	if m.items[nonce] == nil {
+		heap.Push(m.index, nonce)
+	}
+	m.items[nonce], m.cache = tx, nil
+}
+
+// Forward removes all transactions from the map with a nonce lower than the
+// provided threshold. Every removed transaction is returned for any post-removal
+// maintenance.
+func (m *sortedMap) Forward(threshold uint64) types.Transactions {
+	var removed types.Transactions
+
+	// Pop off heap items until the threshold is reached
+	for m.index.Len() > 0 && (*m.index)[0] < threshold {
+		nonce := heap.Pop(m.index).(uint64)
+		removed = append(removed, m.items[nonce])
+		delete(m.items, nonce)
+	}
+	// If we had a cached order, shift the front
+	if m.cache != nil {
+		m.cache = m.cache[len(removed):]
+	}
+	return removed
+}
+
+// Filter iterates over the list of transactions and removes all of them for which
+// the specified function evaluates to true.
+// Filter, as opposed to 'filter', re-initialises the heap after the operation is done.
+// If you want to do several consecutive filterings, it's therefore better to first
+// do a .filter(func1) followed by .Filter(func2) or reheap()
+func (m *sortedMap) Filter(filter func(*types.Transaction) bool) types.Transactions {
+	removed := m.filter(filter)
+	// If transactions were removed, the heap and cache are ruined
+	if len(removed) > 0 {
+		m.reheap()
+	}
+	return removed
+}
+
+func (m *sortedMap) reheap() {
+	*m.index = make([]uint64, 0, len(m.items))
+	for nonce := range m.items {
+		*m.index = append(*m.index, nonce)
+	}
+	heap.Init(m.index)
+	m.cache = nil
+}
+
+// filter is identical to Filter, but **does not** regenerate the heap. This method
+// should only be used if followed immediately by a call to Filter or reheap()
+func (m *sortedMap) filter(filter func(*types.Transaction) bool) types.Transactions {
+	var removed types.Transactions
+
+	// Collect all the transactions to filter out
+	for nonce, tx := range m.items {
+		if filter(tx) {
+			removed = append(removed, tx)
+			delete(m.items, nonce)
+		}
+	}
+	if len(removed) > 0 {
+		m.cache = nil
+	}
+	return removed
+}
+
+// Cap places a hard limit on the number of items, returning all transactions
+// exceeding that limit.
+func (m *sortedMap) Cap(threshold int) types.Transactions {
+	// Short circuit if the number of items is under the limit
+	if len(m.items) <= threshold {
+		return nil
+	}
+	// Otherwise gather and drop the highest nonce'd transactions
+	var drops types.Transactions
+
+	sort.Sort(*m.index)
+	for size := len(m.items); size > threshold; size-- {
+		drops = append(drops, m.items[(*m.index)[size-1]])
+		delete(m.items, (*m.index)[size-1])
+	}
+	*m.index = (*m.index)[:threshold]
+	heap.Init(m.index)
+
+	// If we had a cache, shift the back
+	if m.cache != nil {
+		m.cache = m.cache[:len(m.cache)-len(drops)]
+	}
+	return drops
+}
+
+// Remove deletes a transaction from the maintained map, returning whether the
+// transaction was found.
+func (m *sortedMap) Remove(nonce uint64) bool {
+	// Short circuit if no transaction is present
+	_, ok := m.items[nonce]
+	if !ok {
+		return false
+	}
+	// Otherwise delete the transaction and fix the heap index
+	for i := 0; i < m.index.Len(); i++ {
+		if (*m.index)[i] == nonce {
+			heap.Remove(m.index, i)
+			break
+		}
+	}
+	delete(m.items, nonce)
+	m.cache = nil
+
+	return true
+}
+
+// Ready retrieves a sequentially increasing list of transactions starting at the
+// provided nonce that is ready for processing. The returned transactions will be
+// removed from the list.
+//
+// Note, all transactions with nonces lower than start will also be returned to
+// prevent getting into and invalid state. This is not something that should ever
+// happen but better to be self correcting than failing!
+func (m *sortedMap) Ready(start uint64) types.Transactions {
+	// Short circuit if no transactions are available
+	if m.index.Len() == 0 || (*m.index)[0] > start {
+		return nil
+	}
+	// Otherwise start accumulating incremental transactions
+	var ready types.Transactions
+	for next := (*m.index)[0]; m.index.Len() > 0 && (*m.index)[0] == next; next++ {
+		ready = append(ready, m.items[next])
+		delete(m.items, next)
+		heap.Pop(m.index)
+	}
+	m.cache = nil
+
+	return ready
+}
+
+// Len returns the length of the transaction map.
+func (m *sortedMap) Len() int {
+	return len(m.items)
+}
+
+func (m *sortedMap) flatten() types.Transactions {
+	// If the sorting was not cached yet, create and cache it
+	if m.cache == nil {
+		m.cache = make(types.Transactions, 0, len(m.items))
+		for _, tx := range m.items {
+			m.cache = append(m.cache, tx)
+		}
+		sort.Sort(types.TxByNonce(m.cache))
+	}
+	return m.cache
+}
+
+// Flatten creates a nonce-sorted slice of transactions based on the loosely
+// sorted internal representation. The result of the sorting is cached in case
+// it's requested again before any modifications are made to the contents.
+func (m *sortedMap) Flatten() types.Transactions {
+	// Copy the cache to prevent accidental modifications
+	cache := m.flatten()
+	txs := make(types.Transactions, len(cache))
+	copy(txs, cache)
+	return txs
+}
+
+// LastElement returns the last element of a flattened list, thus, the
+// transaction with the highest nonce
+func (m *sortedMap) LastElement() *types.Transaction {
+	cache := m.flatten()
+	return cache[len(cache)-1]
+}
+
+// list is a "list" of transactions belonging to an account, sorted by account
+// nonce. The same type can be used both for storing contiguous transactions for
+// the executable/pending queue; and for storing gapped transactions for the non-
+// executable/future queue, with minor behavioral changes.
+type list struct {
+	strict bool       // Whether nonces are strictly continuous or not
+	txs    *sortedMap // Heap indexed sorted hash map of the transactions
+
+	costcap *big.Int // Price of the highest costing transaction (reset only if exceeds balance)
+	gascap  uint64   // Gas limit of the highest spending transaction (reset only if exceeds block limit)
+}
+
+// newList create a new transaction list for maintaining nonce-indexable fast,
+// gapped, sortable transaction lists.
+func newList(strict bool) *list {
+	return &list{
+		strict:  strict,
+		txs:     newSortedMap(),
+		costcap: new(big.Int),
+	}
+}
+
+// Overlaps returns whether the transaction specified has the same nonce as one
+// already contained within the list.
+func (l *list) Overlaps(tx *types.Transaction) bool {
+	return l.txs.Get(tx.Nonce()) != nil
+}
+
+// Add tries to insert a new transaction into the list, returning whether the
+// transaction was accepted, and if yes, any previous transaction it replaced.
+//
+// If the new transaction is accepted into the list, the lists' cost and gas
+// thresholds are also potentially updated.
+func (l *list) Add(tx *types.Transaction, priceBump uint64) (bool, *types.Transaction) {
+	// If there's an older better transaction, abort
+	old := l.txs.Get(tx.Nonce())
+	if old != nil {
+		if old.GasFeeCapCmp(tx) >= 0 || old.GasTipCapCmp(tx) >= 0 {
+			return false, nil
+		}
+		// thresholdFeeCap = oldFC  * (100 + priceBump) / 100
+		a := big.NewInt(100 + int64(priceBump))
+		aFeeCap := new(big.Int).Mul(a, old.GasFeeCap())
+		aTip := a.Mul(a, old.GasTipCap())
+
+		// thresholdTip    = oldTip * (100 + priceBump) / 100
+		b := big.NewInt(100)
+		thresholdFeeCap := aFeeCap.Div(aFeeCap, b)
+		thresholdTip := aTip.Div(aTip, b)
+
+		// We have to ensure that both the new fee cap and tip are higher than the
+		// old ones as well as checking the percentage threshold to ensure that
+		// this is accurate for low (Wei-level) gas price replacements.
+		if tx.GasFeeCapIntCmp(thresholdFeeCap) < 0 || tx.GasTipCapIntCmp(thresholdTip) < 0 {
+			return false, nil
+		}
+	}
+	// Otherwise overwrite the old transaction with the current one
+	l.txs.Put(tx)
+	if cost := tx.Cost(); l.costcap.Cmp(cost) < 0 {
+		l.costcap = cost
+	}
+	if gas := tx.Gas(); l.gascap < gas {
+		l.gascap = gas
+	}
+	return true, old
+}
+
+// Forward removes all transactions from the list with a nonce lower than the
+// provided threshold. Every removed transaction is returned for any post-removal
+// maintenance.
+func (l *list) Forward(threshold uint64) types.Transactions {
+	return l.txs.Forward(threshold)
+}
+
+// Filter removes all transactions from the list with a cost or gas limit higher
+// than the provided thresholds. Every removed transaction is returned for any
+// post-removal maintenance. Strict-mode invalidated transactions are also
+// returned.
+//
+// This method uses the cached costcap and gascap to quickly decide if there's even
+// a point in calculating all the costs or if the balance covers all. If the threshold
+// is lower than the costgas cap, the caps will be reset to a new high after removing
+// the newly invalidated transactions.
+func (l *list) Filter(costLimit *big.Int, gasLimit uint64) (types.Transactions, types.Transactions) {
+	// If all transactions are below the threshold, short circuit
+	if l.costcap.Cmp(costLimit) <= 0 && l.gascap <= gasLimit {
+		return nil, nil
+	}
+	l.costcap = new(big.Int).Set(costLimit) // Lower the caps to the thresholds
+	l.gascap = gasLimit
+
+	// Filter out all the transactions above the account's funds
+	removed := l.txs.Filter(func(tx *types.Transaction) bool {
+		return tx.Gas() > gasLimit || tx.Cost().Cmp(costLimit) > 0
+	})
+
+	if len(removed) == 0 {
+		return nil, nil
+	}
+	var invalids types.Transactions
+	// If the list was strict, filter anything above the lowest nonce
+	if l.strict {
+		lowest := uint64(math.MaxUint64)
+		for _, tx := range removed {
+			if nonce := tx.Nonce(); lowest > nonce {
+				lowest = nonce
+			}
+		}
+		invalids = l.txs.filter(func(tx *types.Transaction) bool { return tx.Nonce() > lowest })
+	}
+	l.txs.reheap()
+	return removed, invalids
+}
+
+// Cap places a hard limit on the number of items, returning all transactions
+// exceeding that limit.
+func (l *list) Cap(threshold int) types.Transactions {
+	return l.txs.Cap(threshold)
+}
+
+// Remove deletes a transaction from the maintained list, returning whether the
+// transaction was found, and also returning any transaction invalidated due to
+// the deletion (strict mode only).
+func (l *list) Remove(tx *types.Transaction) (bool, types.Transactions) {
+	// Remove the transaction from the set
+	nonce := tx.Nonce()
+	if removed := l.txs.Remove(nonce); !removed {
+		return false, nil
+	}
+	// In strict mode, filter out non-executable transactions
+	if l.strict {
+		return true, l.txs.Filter(func(tx *types.Transaction) bool { return tx.Nonce() > nonce })
+	}
+	return true, nil
+}
+
+// Ready retrieves a sequentially increasing list of transactions starting at the
+// provided nonce that is ready for processing. The returned transactions will be
+// removed from the list.
+//
+// Note, all transactions with nonces lower than start will also be returned to
+// prevent getting into and invalid state. This is not something that should ever
+// happen but better to be self correcting than failing!
+func (l *list) Ready(start uint64) types.Transactions {
+	return l.txs.Ready(start)
+}
+
+// Len returns the length of the transaction list.
+func (l *list) Len() int {
+	return l.txs.Len()
+}
+
+// Empty returns whether the list of transactions is empty or not.
+func (l *list) Empty() bool {
+	return l.Len() == 0
+}
+
+// Flatten creates a nonce-sorted slice of transactions based on the loosely
+// sorted internal representation. The result of the sorting is cached in case
+// it's requested again before any modifications are made to the contents.
+func (l *list) Flatten() types.Transactions {
+	return l.txs.Flatten()
+}
+
+// LastElement returns the last element of a flattened list, thus, the
+// transaction with the highest nonce
+func (l *list) LastElement() *types.Transaction {
+	return l.txs.LastElement()
+}
+
+// priceHeap is a heap.Interface implementation over transactions for retrieving
+// price-sorted transactions to discard when the pool fills up. If baseFee is set
+// then the heap is sorted based on the effective tip based on the given base fee.
+// If baseFee is nil then the sorting is based on gasFeeCap.
+type priceHeap struct {
+	baseFee *big.Int // heap should always be re-sorted after baseFee is changed
+	list    []*types.Transaction
+}
+
+func (h *priceHeap) Len() int      { return len(h.list) }
+func (h *priceHeap) Swap(i, j int) { h.list[i], h.list[j] = h.list[j], h.list[i] }
+
+func (h *priceHeap) Less(i, j int) bool {
+	switch h.cmp(h.list[i], h.list[j]) {
+	case -1:
+		return true
+	case 1:
+		return false
+	default:
+		return h.list[i].Nonce() > h.list[j].Nonce()
+	}
+}
+
+func (h *priceHeap) cmp(a, b *types.Transaction) int {
+	if h.baseFee != nil {
+		// Compare effective tips if baseFee is specified
+		if c := a.EffectiveGasTipCmp(b, h.baseFee); c != 0 {
+			return c
+		}
+	}
+	// Compare fee caps if baseFee is not specified or effective tips are equal
+	if c := a.GasFeeCapCmp(b); c != 0 {
+		return c
+	}
+	// Compare tips if effective tips and fee caps are equal
+	return a.GasTipCapCmp(b)
+}
+
+func (h *priceHeap) Push(x interface{}) {
+	tx := x.(*types.Transaction)
+	h.list = append(h.list, tx)
+}
+
+func (h *priceHeap) Pop() interface{} {
+	old := h.list
+	n := len(old)
+	x := old[n-1]
+	old[n-1] = nil
+	h.list = old[0 : n-1]
+	return x
+}
+
+// pricedList is a price-sorted heap to allow operating on transactions pool
+// contents in a price-incrementing way. It's built upon the all transactions
+// in txpool but only interested in the remote part. It means only remote transactions
+// will be considered for tracking, sorting, eviction, etc.
+//
+// Two heaps are used for sorting: the urgent heap (based on effective tip in the next
+// block) and the floating heap (based on gasFeeCap). Always the bigger heap is chosen for
+// eviction. Transactions evicted from the urgent heap are first demoted into the floating heap.
+// In some cases (during a congestion, when blocks are full) the urgent heap can provide
+// better candidates for inclusion while in other cases (at the top of the baseFee peak)
+// the floating heap is better. When baseFee is decreasing they behave similarly.
+type pricedList struct {
+	// Number of stale price points to (re-heap trigger).
+	// This field is accessed atomically, and must be the first field
+	// to ensure it has correct alignment for atomic.AddInt64.
+	// See https://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	stales int64
+
+	all              *lookup    // Pointer to the map of all transactions
+	urgent, floating priceHeap  // Heaps of prices of all the stored **remote** transactions
+	reheapMu         sync.Mutex // Mutex asserts that only one routine is reheaping the list
+}
+
+const (
+	// urgentRatio : floatingRatio is the capacity ratio of the two queues
+	urgentRatio   = 4
+	floatingRatio = 1
+)
+
+// newPricedList creates a new price-sorted transaction heap.
+func newPricedList(all *lookup) *pricedList {
+	return &pricedList{
+		all: all,
+	}
+}
+
+// Put inserts a new transaction into the heap.
+func (l *pricedList) Put(tx *types.Transaction, local bool) {
+	if local {
+		return
+	}
+	// Insert every new transaction to the urgent heap first; Discard will balance the heaps
+	heap.Push(&l.urgent, tx)
+}
+
+// Removed notifies the prices transaction list that an old transaction dropped
+// from the pool. The list will just keep a counter of stale objects and update
+// the heap if a large enough ratio of transactions go stale.
+func (l *pricedList) Removed(count int) {
+	// Bump the stale counter, but exit if still too low (< 25%)
+	stales := atomic.AddInt64(&l.stales, int64(count))
+	if int(stales) <= (len(l.urgent.list)+len(l.floating.list))/4 {
+		return
+	}
+	// Seems we've reached a critical number of stale transactions, reheap
+	l.Reheap()
+}
+
+// Underpriced checks whether a transaction is cheaper than (or as cheap as) the
+// lowest priced (remote) transaction currently being tracked.
+func (l *pricedList) Underpriced(tx *types.Transaction) bool {
+	// Note: with two queues, being underpriced is defined as being worse than the worst item
+	// in all non-empty queues if there is any. If both queues are empty then nothing is underpriced.
+	return (l.underpricedFor(&l.urgent, tx) || len(l.urgent.list) == 0) &&
+		(l.underpricedFor(&l.floating, tx) || len(l.floating.list) == 0) &&
+		(len(l.urgent.list) != 0 || len(l.floating.list) != 0)
+}
+
+// underpricedFor checks whether a transaction is cheaper than (or as cheap as) the
+// lowest priced (remote) transaction in the given heap.
+func (l *pricedList) underpricedFor(h *priceHeap, tx *types.Transaction) bool {
+	// Discard stale price points if found at the heap start
+	for len(h.list) > 0 {
+		head := h.list[0]
+		if l.all.GetRemote(head.Hash()) == nil { // Removed or migrated
+			atomic.AddInt64(&l.stales, -1)
+			heap.Pop(h)
+			continue
+		}
+		break
+	}
+	// Check if the transaction is underpriced or not
+	if len(h.list) == 0 {
+		return false // There is no remote transaction at all.
+	}
+	// If the remote transaction is even cheaper than the
+	// cheapest one tracked locally, reject it.
+	return h.cmp(h.list[0], tx) >= 0
+}
+
+// Discard finds a number of most underpriced transactions, removes them from the
+// priced list and returns them for further removal from the entire pool.
+//
+// Note local transaction won't be considered for eviction.
+func (l *pricedList) Discard(slots int, force bool) (types.Transactions, bool) {
+	drop := make(types.Transactions, 0, slots) // Remote underpriced transactions to drop
+	for slots > 0 {
+		if len(l.urgent.list)*floatingRatio > len(l.floating.list)*urgentRatio || floatingRatio == 0 {
+			// Discard stale transactions if found during cleanup
+			tx := heap.Pop(&l.urgent).(*types.Transaction)
+			if l.all.GetRemote(tx.Hash()) == nil { // Removed or migrated
+				atomic.AddInt64(&l.stales, -1)
+				continue
+			}
+			// Non stale transaction found, move to floating heap
+			heap.Push(&l.floating, tx)
+		} else {
+			if len(l.floating.list) == 0 {
+				// Stop if both heaps are empty
+				break
+			}
+			// Discard stale transactions if found during cleanup
+			tx := heap.Pop(&l.floating).(*types.Transaction)
+			if l.all.GetRemote(tx.Hash()) == nil { // Removed or migrated
+				atomic.AddInt64(&l.stales, -1)
+				continue
+			}
+			// Non stale transaction found, discard it
+			drop = append(drop, tx)
+			slots -= numSlots(tx)
+		}
+	}
+	// If we still can't make enough room for the new transaction
+	if slots > 0 && !force {
+		for _, tx := range drop {
+			heap.Push(&l.urgent, tx)
+		}
+		return nil, false
+	}
+	return drop, true
+}
+
+// Reheap forcibly rebuilds the heap based on the current remote transaction set.
+func (l *pricedList) Reheap() {
+	l.reheapMu.Lock()
+	defer l.reheapMu.Unlock()
+	start := time.Now()
+	atomic.StoreInt64(&l.stales, 0)
+	l.urgent.list = make([]*types.Transaction, 0, l.all.RemoteCount())
+	l.all.Range(func(hash common.Hash, tx *types.Transaction, local bool) bool {
+		l.urgent.list = append(l.urgent.list, tx)
+		return true
+	}, false, true) // Only iterate remotes
+	heap.Init(&l.urgent)
+
+	// balance out the two heaps by moving the worse half of transactions into the
+	// floating heap
+	// Note: Discard would also do this before the first eviction but Reheap can do
+	// is more efficiently. Also, Underpriced would work suboptimally the first time
+	// if the floating queue was empty.
+	floatingCount := len(l.urgent.list) * floatingRatio / (urgentRatio + floatingRatio)
+	l.floating.list = make([]*types.Transaction, floatingCount)
+	for i := 0; i < floatingCount; i++ {
+		l.floating.list[i] = heap.Pop(&l.urgent).(*types.Transaction)
+	}
+	heap.Init(&l.floating)
+	reheapTimer.Update(time.Since(start))
+}
+
+// SetBaseFee updates the base fee and triggers a re-heap. Note that Removed is not
+// necessary to call right before SetBaseFee when processing a new block.
+func (l *pricedList) SetBaseFee(baseFee *big.Int) {
+	l.urgent.baseFee = baseFee
+	l.Reheap()
+}

core/txpool/list_test.go

@@ -0,0 +1,72 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package txpool
+
+import (
+	"math/big"
+	"math/rand"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+// Tests that transactions can be added to strict lists and list contents and
+// nonce boundaries are correctly maintained.
+func TestStrictListAdd(t *testing.T) {
+	// Generate a list of transactions to insert
+	key, _ := crypto.GenerateKey()
+
+	txs := make(types.Transactions, 1024)
+	for i := 0; i < len(txs); i++ {
+		txs[i] = transaction(uint64(i), 0, key)
+	}
+	// Insert the transactions in a random order
+	list := newList(true)
+	for _, v := range rand.Perm(len(txs)) {
+		list.Add(txs[v], DefaultConfig.PriceBump)
+	}
+	// Verify internal state
+	if len(list.txs.items) != len(txs) {
+		t.Errorf("transaction count mismatch: have %d, want %d", len(list.txs.items), len(txs))
+	}
+	for i, tx := range txs {
+		if list.txs.items[tx.Nonce()] != tx {
+			t.Errorf("item %d: transaction mismatch: have %v, want %v", i, list.txs.items[tx.Nonce()], tx)
+		}
+	}
+}
+
+func BenchmarkListAdd(b *testing.B) {
+	// Generate a list of transactions to insert
+	key, _ := crypto.GenerateKey()
+
+	txs := make(types.Transactions, 100000)
+	for i := 0; i < len(txs); i++ {
+		txs[i] = transaction(uint64(i), 0, key)
+	}
+	// Insert the transactions in a random order
+	priceLimit := big.NewInt(int64(DefaultConfig.PriceLimit))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		list := newList(true)
+		for _, v := range rand.Perm(len(txs)) {
+			list.Add(txs[v], DefaultConfig.PriceBump)
+			list.Filter(priceLimit, DefaultConfig.PriceBump)
+		}
+	}
+}

core/txpool/noncer.go

@@ -0,0 +1,91 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package txpool
+
+import (
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
+)
+
+// noncer is a tiny virtual state database to manage the executable nonces of
+// accounts in the pool, falling back to reading from a real state database if
+// an account is unknown.
+type noncer struct {
+	fallback *state.StateDB
+	nonces   map[common.Address]uint64
+	lock     sync.Mutex
+}
+
+// newNoncer creates a new virtual state database to track the pool nonces.
+func newNoncer(statedb *state.StateDB) *noncer {
+	return &noncer{
+		fallback: statedb.Copy(),
+		nonces:   make(map[common.Address]uint64),
+	}
+}
+
+// get returns the current nonce of an account, falling back to a real state
+// database if the account is unknown.
+func (txn *noncer) get(addr common.Address) uint64 {
+	// We use mutex for get operation is the underlying
+	// state will mutate db even for read access.
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
+	if _, ok := txn.nonces[addr]; !ok {
+		if nonce := txn.fallback.GetNonce(addr); nonce != 0 {
+			txn.nonces[addr] = nonce
+		}
+	}
+	return txn.nonces[addr]
+}
+
+// set inserts a new virtual nonce into the virtual state database to be returned
+// whenever the pool requests it instead of reaching into the real state database.
+func (txn *noncer) set(addr common.Address, nonce uint64) {
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
+	txn.nonces[addr] = nonce
+}
+
+// setIfLower updates a new virtual nonce into the virtual state database if the
+// new one is lower.
+func (txn *noncer) setIfLower(addr common.Address, nonce uint64) {
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
+	if _, ok := txn.nonces[addr]; !ok {
+		if nonce := txn.fallback.GetNonce(addr); nonce != 0 {
+			txn.nonces[addr] = nonce
+		}
+	}
+	if txn.nonces[addr] <= nonce {
+		return
+	}
+	txn.nonces[addr] = nonce
+}
+
+// setAll sets the nonces for all accounts to the given map.
+func (txn *noncer) setAll(all map[common.Address]uint64) {
+	txn.lock.Lock()
+	defer txn.lock.Unlock()
+
+	txn.nonces = all
+}