Function netisr_init

freebsd/net/netisr.c:1299–1343

* Initialize the netisr subsystem. We rely on BSS and static initialization * of most fields in global data structures. * * Start a worker thread for the boot CPU so that we can support network * traffic immediately in case the network stack is used before additional * CPUs are started (for example, diskless boot). */

 * CPUs are started (for example, diskless boot).
 */
static void
netisr_init(void *arg)
{
	struct pcpu *pc;

	NETISR_LOCK_INIT();
	if (netisr_maxthreads == 0 || netisr_maxthreads < -1 )
		netisr_maxthreads = 1;		/* default behavior */
	else if (netisr_maxthreads == -1)
		netisr_maxthreads = mp_ncpus;	/* use max cpus */
	if (netisr_maxthreads > mp_ncpus) {
		printf("netisr_init: forcing maxthreads from %d to %d\n",
		    netisr_maxthreads, mp_ncpus);
		netisr_maxthreads = mp_ncpus;
	}
	if (netisr_defaultqlimit > netisr_maxqlimit) {
		printf("netisr_init: forcing defaultqlimit from %d to %d\n",
		    netisr_defaultqlimit, netisr_maxqlimit);
		netisr_defaultqlimit = netisr_maxqlimit;
	}
#ifdef DEVICE_POLLING
	/*
	 * The device polling code is not yet aware of how to deal with
	 * multiple netisr threads, so for the time being compiling in device
	 * polling disables parallel netisr workers.
	 */
	if (netisr_maxthreads != 1 || netisr_bindthreads != 0) {
		printf("netisr_init: forcing maxthreads to 1 and "
		    "bindthreads to 0 for device polling\n");
		netisr_maxthreads = 1;
		netisr_bindthreads = 0;
	}
#endif

#ifdef EARLY_AP_STARTUP
	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
		if (nws_count >= netisr_maxthreads)
			break;
		netisr_start_swi(pc->pc_cpuid, pc);
	}
#else
	pc = get_pcpu();
	netisr_start_swi(pc->pc_cpuid, pc);
#endif
}
SYSINIT(netisr_init, SI_SUB_SOFTINTR, SI_ORDER_FIRST, netisr_init, NULL);

#ifndef EARLY_AP_STARTUP