On Mon, 24 Feb 2014, James Hogan wrote: > Hi Thomas, > > On 23/02/14 21:40, Thomas Gleixner wrote: > > There is no point in having an incomplete copy of irq_set_affinity() > > for the hotplug irq migration code. > > That sounds reasonable, but when I gave it a try I started getting > warnings on the log after offlining one cpu then the other: > > META213-Thread0 DSP [LogF] IRQ13 no longer affine to CPU1 > META213-Thread0 DSP [LogF] IRQ14 no longer affine to CPU1 > META213-Thread0 DSP [LogF] IRQ15 no longer affine to CPU1 > META213-Thread0 DSP [LogF] IRQ18 no longer affine to CPU1 > META213-Thread0 DSP [LogF] IRQ29 no longer affine to CPU1 > META213-Thread0 DSP [LogF] IRQ30 no longer affine to CPU1 > META213-Thread0 DSP [LogF] IRQ31 no longer affine to CPU1 > > It appears that the irq affinities weren't getting modified previously, > whereas now irq_do_set_affinity() does do cpumask_copy(data->affinity, > mask). Once all CPUs have been offlined at least once you get those > spurious messages even though the IRQ affinities haven't been explicitly > limited by anything. > > I wonder if the stored affinity should really be altered in this case?
Delta patch below. You need that irq-metag part in any case as the user space interface does not filter out stuff. Assume you offlined core 1 and user changes affinity from 0xf to 0xe. So your selector will pick core 1 which is offline.... Btw, our handling of this is a bit awkward. Right now we let the user do echo 0xf > /proc/irq/$N/smp_affinity and reading that back will give you 0xf though the kernel just selects a subset or even a single target cpu and one has to analyze /proc/interrupts to find out which one. We should add some mechanism to tell the user what's really going on. But that's a separate issue. Thanks, tglx Index: tip/arch/metag/kernel/irq.c =================================================================== --- tip.orig/arch/metag/kernel/irq.c +++ tip/arch/metag/kernel/irq.c @@ -287,10 +287,8 @@ void migrate_irqs(void) i, cpu); cpumask_setall(data->affinity); - newcpu = cpumask_any_and(data->affinity, - cpu_online_mask); } - irq_set_affinity(i, cpumask_of(newcpu)); + irq_set_affinity(i, data->affinity); } } #endif /* CONFIG_HOTPLUG_CPU */ Index: tip/drivers/irqchip/irq-metag.c =================================================================== --- tip.orig/drivers/irqchip/irq-metag.c +++ tip/drivers/irqchip/irq-metag.c @@ -201,7 +201,7 @@ static int metag_internal_irq_set_affini * one cpu (the interrupt code doesn't support it), so we just * pick the first cpu we find in 'cpumask'. */ - cpu = cpumask_any(cpumask); + cpu = cpumask_any_and(cpumask, cpu_online_mask); thread = cpu_2_hwthread_id[cpu]; metag_out32(TBI_TRIG_VEC(TBID_SIGNUM_TR1(thread)), -- To unsubscribe from this list: send the line "unsubscribe linux-metag" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html