`total_memory_tracker.setOrRaiseHardLimit(...);` in `ConfigReloader` callback (see `Server.cpp`).
LockExceptionInThread & operator=(const LockExceptionInThread &) = delete;
        static thread_local uint64_t counter;
        static thread_local VariableContext level;
        static thread_local bool block_fault_injections;
        VariableContext previous_level;
        bool previous_block_fault_injections;
    public:
        
        
        LockExceptionInThread(VariableContext level_ = VariableContext::User, bool block_fault_injections_ = true);
        ~LockExceptionInThread();
        static bool isBlocked(VariableContext current_level, bool fault_injection)
        {
            return counter > 0 && current_level >= level && (!fault_injection || (fault_injection && block_fault_injections));
        }
    };
};
extern MemoryTracker total_memory_tracker;