Re: [RFC][PATCH] genirq: support multiple interrupt priorities

Ingo Molnar
2007-08-06T10:36:28Z

* Paul Mundt <lethal@linux-sh.org> wrote:

> This is a simple patch for adding trivial interrupt priority support.
>
> I've added a ->set_prio() to the irq_chip which is implemented
> effectively the same way as ->set_type(), it's an optional component
> for those that really care about it.

i have no fundamental objections but it would be nice to actually
prototype this by implementing real priority support in the hardware:
both the i8259A and the IO-APIC/local-apic has such IRQ prioritization
features.

> + * IRQF_PRIO_HIGH - Give IRQ a high priority
> + * IRQF_PRIO_LOW - Give IRQ a low priority

this should be a numeric scale. (Preferably in the 1-99 range (the
hardware can then do a lower-resolution thing out of it), so that we can
directly map this to IRQ threads and SCHED_FIFO priorities in -rt.)

Ingo