  In this paper, we study the stability of solutions of stochastic
McKean-Vlasov equations (SMVEs) via feedback control based on discrete-time
state observation. By using a specific Lyapunov function, the $H_{\infty}$
stability, asymptotic stability and exponential stability in mean square for
the solution of the controlled systems are obtained. Since the distribution of
solution is difficult to be observed, we study the corresponding particle
system which can be observed for the feedback control. We prove that the
exponential stability of control system is equivalent to the the exponential
stability of the corresponding particle system. Finally, an example is provided
to show the effectiveness of the theory.
