Only call TrimToSize once per reorg/blocks disconnect

src/main.cpp

@@ -776,7 +776,7 @@ static std::string FormatStateMessage(const CValidationState &state)
 }
 
 bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
-                        bool* pfMissingInputs, bool fRejectAbsurdFee)
+                        bool* pfMissingInputs, bool fOverrideMempoolLimit, bool fRejectAbsurdFee)
 {
     AssertLockHeld(cs_main);
     if (pfMissingInputs)
@@ -956,13 +956,15 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
         pool.addUnchecked(hash, entry, setAncestors, !IsInitialBlockDownload());
 
         // trim mempool and check if tx was trimmed
-        int expired = pool.Expire(GetTime() - GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
-        if (expired != 0)
-            LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);
+        if (!fOverrideMempoolLimit) {
+            int expired = pool.Expire(GetTime() - GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
+            if (expired != 0)
+                LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);
 
-        pool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
-        if (!pool.exists(tx.GetHash()))
-            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
+            pool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+            if (!pool.exists(tx.GetHash()))
+                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
+        }
     }
 
     SyncWithWallets(tx, NULL);
@@ -2029,7 +2031,7 @@ void static UpdateTip(CBlockIndex *pindexNew) {
     }
 }
 
-/** Disconnect chainActive's tip. */
+/** Disconnect chainActive's tip. You want to manually re-limit mempool size after this */
 bool static DisconnectTip(CValidationState &state) {
     CBlockIndex *pindexDelete = chainActive.Tip();
     assert(pindexDelete);
@@ -2056,7 +2058,7 @@ bool static DisconnectTip(CValidationState &state) {
         // ignore validation errors in resurrected transactions
         list<CTransaction> removed;
         CValidationState stateDummy;
-        if (tx.IsCoinBase() || !AcceptToMemoryPool(mempool, stateDummy, tx, false, NULL)) {
+        if (tx.IsCoinBase() || !AcceptToMemoryPool(mempool, stateDummy, tx, false, NULL, true)) {
             mempool.remove(tx, removed, true);
         } else if (mempool.exists(tx.GetHash())) {
             vHashUpdate.push_back(tx.GetHash());
@@ -2229,9 +2231,11 @@ static bool ActivateBestChainStep(CValidationState &state, CBlockIndex *pindexMo
     const CBlockIndex *pindexFork = chainActive.FindFork(pindexMostWork);
 
     // Disconnect active blocks which are no longer in the best chain.
+    bool fBlocksDisconnected = false;
     while (chainActive.Tip() && chainActive.Tip() != pindexFork) {
         if (!DisconnectTip(state))
             return false;
+        fBlocksDisconnected = true;
     }
 
     // Build list of new blocks to connect.
@@ -2277,6 +2281,9 @@ static bool ActivateBestChainStep(CValidationState &state, CBlockIndex *pindexMo
     }
     }
 
+    if (fBlocksDisconnected)
+        mempool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+
     // Callbacks/notifications for a new best chain.
     if (fInvalidFound)
         CheckForkWarningConditionsOnNewFork(vpindexToConnect.back());
@@ -2363,6 +2370,8 @@ bool InvalidateBlock(CValidationState& state, CBlockIndex *pindex) {
         }
     }
 
+    mempool.TrimToSize(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+
     // The resulting new best tip may not be in setBlockIndexCandidates anymore, so
     // add it again.
     BlockMap::iterator it = mapBlockIndex.begin();

src/main.h

@@ -229,7 +229,7 @@ void PruneAndFlush();
 
 /** (try to) add transaction to memory pool **/
 bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
-                        bool* pfMissingInputs, bool fRejectAbsurdFee=false);
+                        bool* pfMissingInputs, bool fOverrideMempoolLimit=false, bool fRejectAbsurdFee=false);
 
 
 struct CNodeStateStats {

src/rpcrawtransaction.cpp

@@ -809,7 +809,7 @@ UniValue sendrawtransaction(const UniValue& params, bool fHelp)
         // push to local node and sync with wallets
         CValidationState state;
         bool fMissingInputs;
-        if (!AcceptToMemoryPool(mempool, state, tx, false, &fMissingInputs, !fOverrideFees)) {
+        if (!AcceptToMemoryPool(mempool, state, tx, false, &fMissingInputs, false, !fOverrideFees)) {
             if (state.IsInvalid()) {
                 throw JSONRPCError(RPC_TRANSACTION_REJECTED, strprintf("%i: %s", state.GetRejectCode(), state.GetRejectReason()));
             } else {

src/test/txvalidationcache_tests.cpp

@@ -23,7 +23,7 @@ ToMemPool(CMutableTransaction& tx)
     LOCK(cs_main);
 
     CValidationState state;
-    return AcceptToMemoryPool(mempool, state, tx, false, NULL, false);
+    return AcceptToMemoryPool(mempool, state, tx, false, NULL, true, false);
 }
 
 BOOST_FIXTURE_TEST_CASE(tx_mempool_block_doublespend, TestChain100Setup)

src/wallet/wallet.cpp

@@ -2863,6 +2863,6 @@ int CMerkleTx::GetBlocksToMaturity() const
 bool CMerkleTx::AcceptToMemoryPool(bool fLimitFree, bool fRejectAbsurdFee)
 {
     CValidationState state;
-    return ::AcceptToMemoryPool(mempool, state, *this, fLimitFree, NULL, fRejectAbsurdFee);
+    return ::AcceptToMemoryPool(mempool, state, *this, fLimitFree, NULL, false, fRejectAbsurdFee);
 }