Re: [patch] Add allowed_affinity to the irq_desc to make it possible to have restricted irqs

From: Ingo Molnar
Date: Wed Dec 13 2006 - 14:45:39 EST



* Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:

> In addition the cases I can think of allowed_affinity is the wrong
> name. suggested_affinity sounds like what you are trying to implement
> and when it is merely a suggestion and not a hard limit it doesn't
> make sense to export like this.

well, there are interrupts that must be tied to a single CPU and must
never be moved away. For example per-CPU clock-events-source interrupts
are such. So allowed_affinity very much exists.

also there might be hardware that can only route a given IRQ to a subset
of CPUs. While setting set_affinity allows the irqbalance-daemon to
'probe' this mask, it's a far from optimal API.

Ingo
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