Re: [RFC 4/6] softirq: Run per-group per-cpu ksoftirqd thread

[Mike Galbraith <efault@gmx.de>]

On Thu, 2018-01-18 at 17:53 +0000, Dmitry Safonov wrote:
> How do you identify in RT one ksoftirqd thread from
> another? I mean, to find which softirq nr the thread is servicing?

static void do_raise_softirq_irqoff(unsigned int nr)
{
	struct task_struct *tsk = __this_cpu_ksoftirqd(nr);
	unsigned int mask = 1UL << nr;

	trace_softirq_raise(nr);
	or_softirq_pending(mask);

	/*
	 * If we are not in a hard interrupt and inside a bh disabled
	 * region, we simply raise the flag on current. local_bh_enable()
	 * will make sure that the softirq is executed. Otherwise we
	 * delegate it to the proper softirqd thread for this softirq.
	 */
	if (!in_irq() && current->softirq_nestcnt) {
		if (!(current->flags & PF_KSOFTIRQD) || current == tsk)
			current->softirqs_raised |= mask;
		else if (tsk) {
			tsk->softirqs_raised |= mask;
			wakeup_softirqd(nr);
		}
	} else if (tsk)
		tsk->softirqs_raised |= mask;
}