Messages in this thread | | | Date | Fri, 12 May 2006 10:10:56 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC][PATCH -rt] irqd starvation on SMP by a single process? |
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* Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 12 May 2006, Ingo Molnar wrote: > > > ah. This actually uncovered a real bug. We were calling __do_softirq() > > with interrupts enabled (and being preemptible) - which is certainly > > bad. > > Hmm, I wonder if this is also affecting Mark's problem. > > But since I showed that if hardirqs_disabled and running PREEMPT not > PREEMPT_RT, disable_irq can call schedule. This is done in > drivers/net/3c59x.c. It has a watchdog timeout calling disable_irq, > which calls synchronize_irq which might schedule: > > void synchronize_irq(unsigned int irq) > { > struct irq_desc *desc = irq_desc + irq; > > if (irq >= NR_IRQS) > return; > > if (hardirq_preemption && !(desc->status & IRQ_NODELAY)) > wait_event(desc->wait_for_handler, > !(desc->status & IRQ_INPROGRESS)); > else > while (desc->status & IRQ_INPROGRESS) > cpu_relax(); > } > > -- Steve > > > > > this was hidden before because the smp_processor_id() debugging code > > handles tasks bound to a single CPU as per-cpu-safe. > > > > could you check the (totally untested) patch below and see if that fixes > > things for you? I've also added your affinity change. > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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