The voms process has a variable for the number of requests that it is serving
https://github.com/italiangrid/voms/blob/2.x/src/server/vomsd.cc#L652

This is increased each time the voms main process accept a connection
https://github.com/italiangrid/voms/blob/2.x/src/server/vomsd.cc#L715
but it is decreased only when the number of active requests reaches the configured maximum for active requests
https://github.com/italiangrid/voms/blob/2.x/src/server/vomsd.cc#L722