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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void Unload() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
    
    void Reset();
    
    
    void MaybeRebalanceCaches() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
};
extern ChainstateManager g_chainman GUARDED_BY(::cs_main);
CChainState& ChainstateActive();
CChain& ChainActive();
extern std::unique_ptr<CBlockTreeDB> pblocktree;
extern VersionBitsCache versionbitscache;
/**
 * Determine what nVersion a new block should use.
 */
int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params);
using FopenFn = std::function<FILE*(const fs::path&, const char*)>;
bool DumpMempool(const CTxMemPool& pool, FopenFn mockable_fopen_function = fsbridge::fopen, bool skip_file_commit = false);
bool LoadMempool(CTxMemPool& pool, CChainState& active_chainstate, FopenFn mockable_fopen_function = fsbridge::fopen);
/**
 * Return the expected assumeutxo value for a given height, if one exists.
 *
 * @param[in] height Get the assumeutxo value for this height.
 *
 * @returns empty if no assumeutxo configuration exists for the given height.
 */
const AssumeutxoData* ExpectedAssumeutxo(const int height, const CChainParams& params);
#endif