There are some potential feefilter cleanups mentioned and motivated in comment https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-805808485 . If you address the locking one, please be careful and make sure that `round()` is only called under a lock. See https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-807992199

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{
        LOCK(cs_main);
        LogPrintf("block tree size = %u\n", chainman.BlockIndex().size());
        chain_active_height = chainman.ActiveChain().Height();
        if (tip_info) {
            tip_info->block_height = chain_active_height;
            tip_info->block_time = chainman.ActiveChain().Tip() ? chainman.ActiveChain().Tip()->GetBlockTime() : Params().GenesisBlock().GetBlockTime();
            tip_info->verification_progress = GuessVerificationProgress(Params().TxData(), chainman.ActiveChain().Tip());
        }
        if (tip_info && ::pindexBestHeader) {
            tip_info->header_height = ::pindexBestHeader->nHeight;
            tip_info->header_time = ::pindexBestHeader->GetBlockTime();
        }
    }
    LogPrintf("nBestHeight = %d\n", chain_active_height);
    if (node.peerman) node.peerman->SetBestHeight(chain_active_height);
    Discover();
     Map ports with UPnP or NAT-PMP.
    StartMapPort(args.GetBoolArg("-upnp", DEFAULT_UPNP), gArgs.GetBoolArg("-natpmp", DEFAULT_NATPMP));
    CConnman::Options connOptions;
    connOptions.nLocalServices = nLocalServices;
    connOptions.nMaxConnections = nMaxConnections;
    connOptions.m_max_outbound_full_relay = std::min(MAX_OUTBOUND_FULL_RELAY_CONNECTIONS, connOptions.nMaxConnections);
    connOptions.m_max_outbound_block_relay = std::min(MAX_BLOCK_RELAY_ONLY_CONNECTIONS, connOptions.nMaxConnections-connOptions.m_max_outbound_full_relay);
    connOptions.nMaxAddnode = MAX_ADDNODE_CONNECTIONS;
    connOptions.nMaxFeeler = MAX_FEELER_CONNECTIONS;