Re: [PATCH 6/6] net: mvneta: Statically assign queues to CPUs

From: Thomas Petazzoni
Date: Fri Jul 03 2015 - 10:46:43 EST


Maxime,

On Fri, 3 Jul 2015 16:25:51 +0200, Maxime Ripard wrote:

> +static void mvneta_percpu_enable(void *arg)
> +{
> + struct mvneta_port *pp = arg;
> +
> + enable_percpu_irq(pp->dev->irq, IRQ_TYPE_NONE);
> +}
> +
> static int mvneta_open(struct net_device *dev)
> {
> struct mvneta_port *pp = netdev_priv(dev);
> @@ -2655,6 +2662,19 @@ static int mvneta_open(struct net_device *dev)
> goto err_cleanup_txqs;
> }
>
> + /*
> + * Even though the documentation says that request_percpu_irq
> + * doesn't enable the interrupts automatically, it actually
> + * does so on the local CPU.
> + *
> + * Make sure it's disabled.
> + */
> + disable_percpu_irq(pp->dev->irq);
> +
> + /* Enable per-CPU interrupt on the one CPU we care about */
> + smp_call_function_single(rxq_def % num_online_cpus(),
> + mvneta_percpu_enable, pp, true);

What happens if that CPU goes offline through CPU hotplug?

Thanks!

Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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