taglinefilesource code
ssthresh855net/inet/sock.csk->ssthresh = 0;
ssthresh115net/inet/sock.hvolatile unsigned short  ssthresh;
ssthresh226net/inet/tcp.csk->ssthresh = sk->cong_window >> 1; /* remember window where we lost */
ssthresh1776net/inet/tcp.cnewsk->ssthresh = 0;
ssthresh2271net/inet/tcp.cif (sk->cong_window < sk->ssthresh)