Re: [PATCH 3/5] irq_work: Implement remote queueing

From: Eric Dumazet
Date: Tue Jun 03 2014 - 16:02:45 EST


On Tue, 2014-06-03 at 18:37 +0200, Peter Zijlstra wrote:
> On Tue, Jun 03, 2014 at 09:29:07AM -0700, Eric Dumazet wrote:
> > > +bool irq_work_queue_on(struct irq_work *work, int cpu)
> > > +{
> > > + /* All work should have been flushed before going offline */
> > > + WARN_ON_ONCE(cpu_is_offline(cpu));
> > > +
> > > + /* Arch remote IPI send/receive backend aren't NMI safe */
> > > + WARN_ON_ONCE(in_nmi());
> > > +
> > > + /* Only queue if not already pending */
> > > + if (!irq_work_claim(work))
> > > + return false;
> > > +
> > > + if (llist_add(&work->llnode, &per_cpu(raised_list, cpu)))
> > > + native_send_call_func_single_ipi(cpu);
> > > +
> > > + return true;
> > > +}
> > > +EXPORT_SYMBOL_GPL(irq_work_queue_on);
> > > +
> >
> > I am curious, this should only compile on x86, right ?
>
> Oh, you tease, you forgot to say why you think this.
>
> Are you referring to the in_nmi() usage? that's from
> include/linux/hardirq.h, hardly x86 specific.

No, my eyes were attracted by native_send_call_func_single_ipi()




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