Re: [PATCH] genirq: don't use flush_scheduled_work() in IRQaffinity notifiers

From: Ben Hutchings
Date: Thu Jun 16 2011 - 19:28:41 EST


On Wed, 2011-06-15 at 16:29 +0200, Tejun Heo wrote:
> cd7eab44e9 (genirq: Add IRQ affinity notifiers) added use of
> flush_scheduled_work() which is being deprecated. Add a dedicated
> workqueue and flush it instead of flushing system-wide workqueue.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
> ---
> I'm planning on marking flush_scheduled_work() deprecated in
> linux-next soonish. It would be great if this patch (or something
> else which removes flush_scheduled_work() call somehow) can be
> included in linux-next.
[...]
> --- work.orig/kernel/irq/manage.c
> +++ work/kernel/irq/manage.c
> @@ -74,6 +74,16 @@ EXPORT_SYMBOL(synchronize_irq);
>
> #ifdef CONFIG_SMP
> cpumask_var_t irq_default_affinity;
> +static struct workqueue_struct *irq_affinity_notify_wq;
> +
> +static int __init irq_affinity_init(void)
> +{
> + irq_affinity_notify_wq = alloc_workqueue("irq_affinity_notify", 0, 0);
> + if (!irq_affinity_notify_wq)
> + return -ENOMEM;
> + return 0;
> +}
> +subsys_initcall(irq_affinity_init);
[...]

This facility is enabled on all configurations with NET && SMP &&
GENERIC_HARDIRQS, but at the moment is only useful for some net drivers
(currently only one). So I don't think it should be creating a task at
boot time. Does alloc_workqueue() still create any tasks immediately?

Ben.

--
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

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