Merge bitcoin/bitcoin#28385: [refactor] rewrite DisconnectedBlockTransactions to not use boost

src/Makefile.am

@@ -282,6 +282,7 @@ BITCOIN_CORE_H = \
   node/coinstats.h \
   node/connection_types.h \
   node/context.h \
+  node/disconnected_transactions.h \
   node/eviction.h \
   node/miner.h \
   node/minisketchwrapper.h \

src/Makefile.bench.include

@@ -25,6 +25,8 @@ bench_bench_dash_SOURCES = \
   bench/checkqueue.cpp \
   bench/data.h \
   bench/data.cpp \
+  bench/descriptors.cpp \
+  bench/disconnected_transactions.cpp \
   bench/duplicate_inputs.cpp \
   bench/ecdsa.cpp \
   bench/ellswift.cpp \

src/bench/disconnected_transactions.cpp

@@ -0,0 +1,130 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <bench/bench.h>
+#include <kernel/disconnected_transactions.h>
+#include <primitives/block.h>
+#include <test/util/random.h>
+#include <test/util/setup_common.h>
+
+constexpr size_t BLOCK_VTX_COUNT{4000};
+constexpr size_t BLOCK_VTX_COUNT_10PERCENT{400};
+
+using BlockTxns = decltype(CBlock::vtx);
+
+/** Reorg where 1 block is disconnected and 2 blocks are connected. */
+struct ReorgTxns {
+    /** Disconnected block. */
+    BlockTxns disconnected_txns;
+    /** First connected block. */
+    BlockTxns connected_txns_1;
+    /** Second connected block, new chain tip. Has no overlap with disconnected_txns. */
+    BlockTxns connected_txns_2;
+    /** Transactions shared between disconnected_txns and connected_txns_1. */
+    size_t num_shared;
+};
+
+static BlockTxns CreateRandomTransactions(size_t num_txns)
+{
+    // Ensure every transaction has a different txid by having each one spend the previous one.
+    static uint256 prevout_hash{uint256::ZERO};
+
+    BlockTxns txns;
+    txns.reserve(num_txns);
+    // Simplest spk for every tx
+    CScript spk = CScript() << OP_TRUE;
+    for (uint32_t i = 0; i < num_txns; ++i) {
+        CMutableTransaction tx;
+        tx.vin.emplace_back(CTxIn{COutPoint{prevout_hash, 0}});
+        tx.vout.emplace_back(CTxOut{CENT, spk});
+        auto ptx{MakeTransactionRef(tx)};
+        txns.emplace_back(ptx);
+        prevout_hash = ptx->GetHash();
+    }
+    return txns;
+}
+
+/** Creates blocks for a Reorg, each with BLOCK_VTX_COUNT transactions. Between the disconnected
+ * block and the first connected block, there will be num_not_shared transactions that are
+ * different, and all other transactions the exact same. The second connected block has all unique
+ * transactions. This is to simulate a reorg in which all but num_not_shared transactions are
+ * confirmed in the new chain. */
+static ReorgTxns CreateBlocks(size_t num_not_shared)
+{
+    auto num_shared{BLOCK_VTX_COUNT - num_not_shared};
+    const auto shared_txns{CreateRandomTransactions(/*num_txns=*/num_shared)};
+
+    // Create different sets of transactions...
+    auto disconnected_block_txns{CreateRandomTransactions(/*num_txns=*/num_not_shared)};
+    std::copy(shared_txns.begin(), shared_txns.end(), std::back_inserter(disconnected_block_txns));
+
+    auto connected_block_txns{CreateRandomTransactions(/*num_txns=*/num_not_shared)};
+    std::copy(shared_txns.begin(), shared_txns.end(), std::back_inserter(connected_block_txns));
+
+    assert(disconnected_block_txns.size() == BLOCK_VTX_COUNT);
+    assert(connected_block_txns.size() == BLOCK_VTX_COUNT);
+
+    return ReorgTxns{/*disconnected_txns=*/disconnected_block_txns,
+                     /*connected_txns_1=*/connected_block_txns,
+                     /*connected_txns_2=*/CreateRandomTransactions(BLOCK_VTX_COUNT),
+                     /*num_shared=*/num_shared};
+}
+
+static void Reorg(const ReorgTxns& reorg)
+{
+    DisconnectedBlockTransactions disconnectpool{MAX_DISCONNECTED_TX_POOL_SIZE * 1000};
+    // Disconnect block
+    const auto evicted = disconnectpool.AddTransactionsFromBlock(reorg.disconnected_txns);
+    assert(evicted.empty());
+
+    // Connect first block
+    disconnectpool.removeForBlock(reorg.connected_txns_1);
+    // Connect new tip
+    disconnectpool.removeForBlock(reorg.connected_txns_2);
+
+    // Sanity Check
+    assert(disconnectpool.size() == BLOCK_VTX_COUNT - reorg.num_shared);
+
+    disconnectpool.clear();
+}
+
+/** Add transactions from DisconnectedBlockTransactions, remove all but one (the disconnected
+ * block's coinbase transaction) of them, and then pop from the front until empty. This is a reorg
+ * in which all of the non-coinbase transactions in the disconnected chain also exist in the new
+ * chain. */
+static void AddAndRemoveDisconnectedBlockTransactionsAll(benchmark::Bench& bench)
+{
+    const auto chains{CreateBlocks(/*num_not_shared=*/1)};
+    assert(chains.num_shared == BLOCK_VTX_COUNT - 1);
+
+    bench.minEpochIterations(10).run([&]() NO_THREAD_SAFETY_ANALYSIS {
+        Reorg(chains);
+    });
+}
+
+/** Add transactions from DisconnectedBlockTransactions, remove 90% of them, and then pop from the front until empty. */
+static void AddAndRemoveDisconnectedBlockTransactions90(benchmark::Bench& bench)
+{
+    const auto chains{CreateBlocks(/*num_not_shared=*/BLOCK_VTX_COUNT_10PERCENT)};
+    assert(chains.num_shared == BLOCK_VTX_COUNT - BLOCK_VTX_COUNT_10PERCENT);
+
+    bench.minEpochIterations(10).run([&]() NO_THREAD_SAFETY_ANALYSIS {
+        Reorg(chains);
+    });
+}
+
+/** Add transactions from DisconnectedBlockTransactions, remove 10% of them, and then pop from the front until empty. */
+static void AddAndRemoveDisconnectedBlockTransactions10(benchmark::Bench& bench)
+{
+    const auto chains{CreateBlocks(/*num_not_shared=*/BLOCK_VTX_COUNT - BLOCK_VTX_COUNT_10PERCENT)};
+    assert(chains.num_shared == BLOCK_VTX_COUNT_10PERCENT);
+
+    bench.minEpochIterations(10).run([&]() NO_THREAD_SAFETY_ANALYSIS {
+        Reorg(chains);
+    });
+}
+
+BENCHMARK(AddAndRemoveDisconnectedBlockTransactionsAll, benchmark::PriorityLevel::HIGH);
+BENCHMARK(AddAndRemoveDisconnectedBlockTransactions90, benchmark::PriorityLevel::HIGH);
+BENCHMARK(AddAndRemoveDisconnectedBlockTransactions10, benchmark::PriorityLevel::HIGH);

src/memusage.h

@@ -11,6 +11,7 @@
 
 #include <cassert>
 #include <cstdlib>
+#include <list>
 #include <map>
 #include <memory>
 #include <set>
@@ -148,6 +149,21 @@ static inline size_t DynamicUsage(const std::shared_ptr<X>& p)
     return p ? MallocUsage(sizeof(X)) + MallocUsage(sizeof(stl_shared_counter)) : 0;
 }
 
+template<typename X>
+struct list_node
+{
+private:
+    void* ptr_next;
+    void* ptr_prev;
+    X x;
+};
+
+template<typename X>
+static inline size_t DynamicUsage(const std::list<X>& l)
+{
+    return MallocUsage(sizeof(list_node<X>)) * l.size();
+}
+
 template<typename X>
 struct unordered_node : private X
 {

src/node/disconnected_transactions.h

@@ -0,0 +1,137 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_KERNEL_DISCONNECTED_TRANSACTIONS_H
+#define BITCOIN_KERNEL_DISCONNECTED_TRANSACTIONS_H
+
+#include <core_memusage.h>
+#include <memusage.h>
+#include <primitives/transaction.h>
+#include <util/hasher.h>
+
+#include <list>
+#include <unordered_map>
+#include <vector>
+
+/** Maximum kilobytes for transactions to store for processing during reorg */
+static const unsigned int MAX_DISCONNECTED_TX_POOL_SIZE = 20'000;
+/**
+ * DisconnectedBlockTransactions
+
+ * During the reorg, it's desirable to re-add previously confirmed transactions
+ * to the mempool, so that anything not re-confirmed in the new chain is
+ * available to be mined. However, it's more efficient to wait until the reorg
+ * is complete and process all still-unconfirmed transactions at that time,
+ * since we expect most confirmed transactions to (typically) still be
+ * confirmed in the new chain, and re-accepting to the memory pool is expensive
+ * (and therefore better to not do in the middle of reorg-processing).
+ * Instead, store the disconnected transactions (in order!) as we go, remove any
+ * that are included in blocks in the new chain, and then process the remaining
+ * still-unconfirmed transactions at the end.
+ *
+ * Order of queuedTx:
+ * The front of the list should be the most recently-confirmed transactions (transactions at the
+ * end of vtx of blocks closer to the tip). If memory usage grows too large, we trim from the front
+ * of the list. After trimming, transactions can be re-added to the mempool from the back of the
+ * list to the front without running into missing inputs.
+ */
+class DisconnectedBlockTransactions {
+private:
+    /** Cached dynamic memory usage for the CTransactions (memory for the shared pointers is
+     * included in the container calculations). */
+    uint64_t cachedInnerUsage = 0;
+    const size_t m_max_mem_usage;
+    std::list<CTransactionRef> queuedTx;
+    using TxList = decltype(queuedTx);
+    std::unordered_map<uint256, TxList::iterator, SaltedTxidHasher> iters_by_txid;
+
+    /** Trim the earliest-added entries until we are within memory bounds. */
+    std::vector<CTransactionRef> LimitMemoryUsage()
+    {
+        std::vector<CTransactionRef> evicted;
+
+        while (!queuedTx.empty() && DynamicMemoryUsage() > m_max_mem_usage) {
+            evicted.emplace_back(queuedTx.front());
+            cachedInnerUsage -= RecursiveDynamicUsage(*queuedTx.front());
+            iters_by_txid.erase(queuedTx.front()->GetHash());
+            queuedTx.pop_front();
+        }
+        return evicted;
+    }
+
+public:
+    DisconnectedBlockTransactions(size_t max_mem_usage) : m_max_mem_usage{max_mem_usage} {}
+
+    // It's almost certainly a logic bug if we don't clear out queuedTx before
+    // destruction, as we add to it while disconnecting blocks, and then we
+    // need to re-process remaining transactions to ensure mempool consistency.
+    // For now, assert() that we've emptied out this object on destruction.
+    // This assert() can always be removed if the reorg-processing code were
+    // to be refactored such that this assumption is no longer true (for
+    // instance if there was some other way we cleaned up the mempool after a
+    // reorg, besides draining this object).
+    ~DisconnectedBlockTransactions() {
+        assert(queuedTx.empty());
+        assert(iters_by_txid.empty());
+        assert(cachedInnerUsage == 0);
+    }
+
+    size_t DynamicMemoryUsage() const {
+        return cachedInnerUsage + memusage::DynamicUsage(iters_by_txid) + memusage::DynamicUsage(queuedTx);
+    }
+
+    /** Add transactions from the block, iterating through vtx in reverse order. Callers should call
+     * this function for blocks in descending order by block height.
+     * We assume that callers never pass multiple transactions with the same txid, otherwise things
+     * can go very wrong in removeForBlock due to queuedTx containing an item without a
+     * corresponding entry in iters_by_txid.
+     * @returns vector of transactions that were evicted for size-limiting.
+     */
+    [[nodiscard]] std::vector<CTransactionRef> AddTransactionsFromBlock(const std::vector<CTransactionRef>& vtx)
+    {
+        iters_by_txid.reserve(iters_by_txid.size() + vtx.size());
+        for (auto block_it = vtx.rbegin(); block_it != vtx.rend(); ++block_it) {
+            auto it = queuedTx.insert(queuedTx.end(), *block_it);
+            iters_by_txid.emplace((*block_it)->GetHash(), it);
+            cachedInnerUsage += RecursiveDynamicUsage(**block_it);
+        }
+        return LimitMemoryUsage();
+    }
+
+    /** Remove any entries that are in this block. */
+    void removeForBlock(const std::vector<CTransactionRef>& vtx)
+    {
+        // Short-circuit in the common case of a block being added to the tip
+        if (queuedTx.empty()) {
+            return;
+        }
+        for (const auto& tx : vtx) {
+            auto iter = iters_by_txid.find(tx->GetHash());
+            if (iter != iters_by_txid.end()) {
+                auto list_iter = iter->second;
+                iters_by_txid.erase(iter);
+                cachedInnerUsage -= RecursiveDynamicUsage(**list_iter);
+                queuedTx.erase(list_iter);
+            }
+        }
+    }
+
+    size_t size() const { return queuedTx.size(); }
+
+    void clear()
+    {
+        cachedInnerUsage = 0;
+        iters_by_txid.clear();
+        queuedTx.clear();
+    }
+
+    /** Clear all data structures and return the list of transactions. */
+    std::list<CTransactionRef> take()
+    {
+        std::list<CTransactionRef> ret = std::move(queuedTx);
+        clear();
+        return ret;
+    }
+};
+#endif // BITCOIN_KERNEL_DISCONNECTED_TRANSACTIONS_H

src/test/validation_chainstatemanager_tests.cpp

@@ -9,6 +9,7 @@
 #include <llmq/blockprocessor.h>
 #include <llmq/context.h>
 #include <node/chainstate.h>
+#include <node/disconnected_transactions.h>
 #include <node/utxo_snapshot.h>
 #include <random.h>
 #include <rpc/blockchain.h>