On Tue, Sep 9, 2008 at 5:50 PM, Jeremy Fitzhardinge  wrote:

quoted text
> Yinghai Lu wrote:

>> On Tue, Sep 9, 2008 at 4:46 PM, Jeremy Fitzhardinge  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?

for phys_flat mode: it will get new vector for on new cpu.
>

quoted text
> 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?

seems need to rework __assign_irq_vector a little bit.
to

cpumask_t (*vector_allocation_domain_t)(int cpu)

static int __assign_irq_vector(int irq, cpumask_t mask,

vector_allocation_domain_t p)
...
and you could have your own
static cpumask_t vec_domain_alloc(int cpu)

{

        cpumask_t domain = cpu_possible_map;

        return domain;

}
static int assign_irq_vector_all(int irq)

{

        int err;

        unsigned long flags;

        cpumask_t mask = cpu_possible_map;
        spin_lock_irqsave(&vector_lock, flags);

        err = __assign_irq_vector(irq, mask, vec_domain_alloc);

        spin_unlock_irqrestore(&vector_lock, flags);

        return err;

}
YH

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