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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150703164624.77188a63@free-electrons.com>
Date:	Fri, 3 Jul 2015 16:46:24 +0200
From:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
To:	Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Gregory Clement <gregory.clement@...e-electrons.com>,
	Jason Cooper <jason@...edaemon.net>,
	Andrew Lunn <andrew@...n.ch>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH 6/6] net: mvneta: Statically assign queues to CPUs

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/