Function lock_delay

freebsd/kern/subr_lock.c:124–143

    &restrict_starvation, 0, "");

void
lock_delay(struct lock_delay_arg *la)
{
	struct lock_delay_config *lc = la->config;
	u_short i;

	la->delay <<= 1;
	if (__predict_false(la->delay > lc->max))
		la->delay = lc->max;

	for (i = la->delay; i > 0; i--)
		cpu_spinwait();

	la->spin_cnt += la->delay;
	if (__predict_false(la->spin_cnt > starvation_limit)) {
		SDT_PROBE1(lock, , , starvation, la->delay);
		if (restrict_starvation)
			la->delay = lc->base;
	}
}

static u_int
lock_roundup_2(u_int val)