Re: TARGET_CPUS in assign_irq_vector

[Jeremy Fitzhardinge <jeremy@goop.org>]

Yinghai Lu wrote:
> On Tue, Sep 9, 2008 at 4:46 PM, Jeremy Fitzhardinge <jeremy@goop.org> 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