rpc: Return total fee in mempool

Also, add missing lock annotations

5 files changed, 32 insertions, 14 deletions

diff --git a/doc/REST-interface.md b/doc/REST-interface.md
index 6237734390..ea06952af4 100644
--- a/doc/REST-interface.md
+++ b/doc/REST-interface.md
@@ -111,12 +111,7 @@ $ curl localhost:18332/rest/getutxos/checkmempool/b2cdfd7b89def827ff8af7cd9bff76
 
 Returns various information about the TX mempool.
 Only supports JSON as output format.
-* loaded : (boolean) if the mempool is fully loaded
-* size : (numeric) the number of transactions in the TX mempool
-* bytes : (numeric) size of the TX mempool in bytes
-* usage : (numeric) total TX mempool memory usage
-* maxmempool : (numeric) maximum memory usage for the mempool in bytes
-* mempoolminfee : (numeric) minimum feerate (BTC per KB) for tx to be accepted
+Refer to the `getmempoolinfo` RPC for documentation of the fields.
 
 `GET /rest/mempool/contents.json`
 
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 7a336c1ad6..c454ba6963 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -17,8 +17,8 @@
 #include <node/coinstats.h>
 #include <node/context.h>
 #include <node/utxo_snapshot.h>
-#include <policy/fees.h>
 #include <policy/feerate.h>
+#include <policy/fees.h>
 #include <policy/policy.h>
 #include <policy/rbf.h>
 #include <primitives/transaction.h>
@@ -1500,6 +1500,7 @@ UniValue MempoolInfoToJSON(const CTxMemPool& pool)
     ret.pushKV("size", (int64_t)pool.size());
     ret.pushKV("bytes", (int64_t)pool.GetTotalTxSize());
     ret.pushKV("usage", (int64_t)pool.DynamicMemoryUsage());
+    ret.pushKV("total_fee", ValueFromAmount(pool.GetTotalFee()));
     size_t maxmempool = gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     ret.pushKV("maxmempool", (int64_t) maxmempool);
     ret.pushKV("mempoolminfee", ValueFromAmount(std::max(pool.GetMinFee(maxmempool), ::minRelayTxFee).GetFeePerK()));
@@ -1520,6 +1521,7 @@ static RPCHelpMan getmempoolinfo()
                         {RPCResult::Type::NUM, "size", "Current tx count"},
                         {RPCResult::Type::NUM, "bytes", "Sum of all virtual transaction sizes as defined in BIP 141. Differs from actual serialized size because witness data is discounted"},
                         {RPCResult::Type::NUM, "usage", "Total memory usage for the mempool"},
+                        {RPCResult::Type::STR_AMOUNT, "total_fee", "Total fees for the mempool in " + CURRENCY_UNIT + ", ignoring modified fees through prioritizetransaction"},
                         {RPCResult::Type::NUM, "maxmempool", "Maximum memory usage for the mempool"},
                         {RPCResult::Type::STR_AMOUNT, "mempoolminfee", "Minimum fee rate in " + CURRENCY_UNIT + "/kB for tx to be accepted. Is the maximum of minrelaytxfee and minimum mempool fee"},
                         {RPCResult::Type::STR_AMOUNT, "minrelaytxfee", "Current minimum relay fee for transactions"},
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 470e665844..33565988e4 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -9,14 +9,14 @@
 #include <consensus/tx_verify.h>
 #include <consensus/validation.h>
 #include <optional.h>
-#include <validation.h>
-#include <policy/policy.h>
 #include <policy/fees.h>
+#include <policy/policy.h>
 #include <policy/settings.h>
 #include <reverse_iterator.h>
-#include <util/system.h>
 #include <util/moneystr.h>
+#include <util/system.h>
 #include <util/time.h>
+#include <validation.h>
 #include <validationinterface.h>
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTransactionRef& _tx, const CAmount& _nFee,
@@ -396,7 +396,10 @@ void CTxMemPool::addUnchecked(const CTxMemPoolEntry &entry, setEntries &setAnces
 
     nTransactionsUpdated++;
     totalTxSize += entry.GetTxSize();
-    if (minerPolicyEstimator) {minerPolicyEstimator->processTransaction(entry, validFeeEstimate);}
+    m_total_fee += entry.GetFee();
+    if (minerPolicyEstimator) {
+        minerPolicyEstimator->processTransaction(entry, validFeeEstimate);
+    }
 
     vTxHashes.emplace_back(tx.GetWitnessHash(), newit);
     newit->vTxHashesIdx = vTxHashes.size() - 1;
@@ -432,6 +435,7 @@ void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason)
         vTxHashes.clear();
 
     totalTxSize -= it->GetTxSize();
+    m_total_fee -= it->GetFee();
     cachedInnerUsage -= it->DynamicMemoryUsage();
     cachedInnerUsage -= memusage::DynamicUsage(it->GetMemPoolParentsConst()) + memusage::DynamicUsage(it->GetMemPoolChildrenConst());
     mapTx.erase(it);
@@ -590,6 +594,7 @@ void CTxMemPool::_clear()
     mapTx.clear();
     mapNextTx.clear();
     totalTxSize = 0;
+    m_total_fee = 0;
     cachedInnerUsage = 0;
     lastRollingFeeUpdate = GetTime();
     blockSinceLastRollingFeeBump = false;
@@ -623,6 +628,7 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
     LogPrint(BCLog::MEMPOOL, "Checking mempool with %u transactions and %u inputs\n", (unsigned int)mapTx.size(), (unsigned int)mapNextTx.size());
 
     uint64_t checkTotal = 0;
+    CAmount check_total_fee{0};
     uint64_t innerUsage = 0;
 
     CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache*>(pcoins));
@@ -632,6 +638,7 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
     for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
         unsigned int i = 0;
         checkTotal += it->GetTxSize();
+        check_total_fee += it->GetFee();
         innerUsage += it->DynamicMemoryUsage();
         const CTransaction& tx = it->GetTx();
         innerUsage += memusage::DynamicUsage(it->GetMemPoolParentsConst()) + memusage::DynamicUsage(it->GetMemPoolChildrenConst());
@@ -726,6 +733,7 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
     }
 
     assert(totalTxSize == checkTotal);
+    assert(m_total_fee == check_total_fee);
     assert(innerUsage == cachedInnerUsage);
 }
 
diff --git a/src/txmempool.h b/src/txmempool.h
index 0a9cd81ff5..c0df33fe13 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -19,8 +19,8 @@
 #include <optional.h>
 #include <policy/feerate.h>
 #include <primitives/transaction.h>
-#include <sync.h>
 #include <random.h>
+#include <sync.h>
 #include <util/hasher.h>
 
 #include <boost/multi_index_container.hpp>
@@ -478,8 +478,9 @@ private:
     std::atomic<unsigned int> nTransactionsUpdated{0}; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation
     CBlockPolicyEstimator* minerPolicyEstimator;
 
-    uint64_t totalTxSize;      //!< sum of all mempool tx's virtual sizes. Differs from serialized tx size since witness data is discounted. Defined in BIP 141.
-    uint64_t cachedInnerUsage; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
+    uint64_t totalTxSize GUARDED_BY(cs);      //!< sum of all mempool tx's virtual sizes. Differs from serialized tx size since witness data is discounted. Defined in BIP 141.
+    CAmount m_total_fee GUARDED_BY(cs);       //!< sum of all mempool tx's fees (NOT modified fee)
+    uint64_t cachedInnerUsage GUARDED_BY(cs); //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
 
     mutable int64_t lastRollingFeeUpdate;
     mutable bool blockSinceLastRollingFeeBump;
@@ -724,6 +725,12 @@ public:
         return totalTxSize;
     }
 
+    CAmount GetTotalFee() const EXCLUSIVE_LOCKS_REQUIRED(cs)
+    {
+        AssertLockHeld(cs);
+        return m_total_fee;
+    }
+
     bool exists(const GenTxid& gtxid) const
     {
         LOCK(cs);
diff --git a/test/functional/mempool_persist.py b/test/functional/mempool_persist.py
index 70cd4ebb3b..752b925b92 100755
--- a/test/functional/mempool_persist.py
+++ b/test/functional/mempool_persist.py
@@ -69,6 +69,8 @@ class MempoolPersistTest(BitcoinTestFramework):
         assert_equal(len(self.nodes[0].getrawmempool()), 5)
         assert_equal(len(self.nodes[1].getrawmempool()), 5)
 
+        total_fee_old = self.nodes[0].getmempoolinfo()['total_fee']
+
         self.log.debug("Prioritize a transaction on node0")
         fees = self.nodes[0].getmempoolentry(txid=last_txid)['fees']
         assert_equal(fees['base'], fees['modified'])
@@ -76,6 +78,10 @@ class MempoolPersistTest(BitcoinTestFramework):
         fees = self.nodes[0].getmempoolentry(txid=last_txid)['fees']
         assert_equal(fees['base'] + Decimal('0.00001000'), fees['modified'])
 
+        self.log.info('Check the total base fee is unchanged after prioritisetransaction')
+        assert_equal(total_fee_old, self.nodes[0].getmempoolinfo()['total_fee'])
+        assert_equal(total_fee_old, sum(v['fees']['base'] for k, v in self.nodes[0].getrawmempool(verbose=True).items()))
+
         tx_creation_time = self.nodes[0].getmempoolentry(txid=last_txid)['time']
         assert_greater_than_or_equal(tx_creation_time, tx_creation_time_lower)
         assert_greater_than_or_equal(tx_creation_time_higher, tx_creation_time)