> The policy that defines what is [memory pressure](https://wwwx.cs.unc.edu/~sparkst/howto/network_tuning.php) is specified at tcp_mem and tcp_moderate_rcvbuf.
The step about qdisc on ingress side is incorrect.
By default there is no ingress queue discipline.
It is possible to add ingress qdisc, but it is not the default qdisc. The ingress qdisc is special, it never queues packet it only does actions like policing or redirect.