est_timer
unsigned long est_timer; /* estimation timer (jiffies) */
timer_setup(&est->timer, est_timer, 0);
gap = kd->est_timer - now;
kd->est_timer = now - IPVS_EST_TICK;
kd->est_timer = now;
kd->est_timer += IPVS_EST_TICK;
gap = kd->est_timer - now;
kd->est_timer = now;
kd->est_timer = jiffies;