taglinefilesource code
xmit_idle531drivers/net/ppp.cppp->ddinfo.xmit_idle=         /* time since last NP packet sent */
xmit_idle2511drivers/net/ppp.ccur_ddinfo.xmit_idle = (cur_jiffies - ppp->ddinfo.xmit_idle) / HZ;
xmit_idle3187drivers/net/ppp.cppp->ddinfo.xmit_idle = jiffies;
xmit_idle163include/linux/ppp_defs.htime_t xmit_idle;    /* time since last NP packet sent */