Re: TARGET_CPUS in assign_irq_vector

From: Jeremy Fitzhardinge
Date: Tue Sep 09 2008 - 20:50:25 EST


Yinghai Lu wrote:
> On Tue, Sep 9, 2008 at 4:46 PM, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>
>> Yinghai Lu wrote:
>>
>>> target_cpus is the cpus that could be possible to used to take vector
>>> and process that irq. so at least it should be online.
>>>
>>>
>> Would it be wrong to make it possible_cpu_mask?
>>
>>
> it is wrong

What happens if you online a new cpu and migrate the irq to it? Does it
get allocated a new vector?

I'm using create_irq() as a general irq and vector allocation mechanism
for Xen interrupts. I'd like to be able to allocate a vector across all
possible cpus so I can bind Xen event channels to vectors. Should I: 1)
add a create_irq_cpus() which takes a cpu mask rather than defaulting to
TARGET_CPUS, 2) modify struct genapic to insert by own target_cpus(),
3) give up because the idea is fundamentally ill-conceived, or 4)
something else?

Thanks,
J

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