Bjorn Helgaas bhelgaas at google.com
Sat Jul 18 03:50:05 AEST 2015

On Fri, Jul 17, 2015 at 9:06 AM, Thomas Gleixner <tglx at linutronix.de> wrote:
> On Sun, 12 Jul 2015, Bjorn Helgaas wrote:
>> The per-cpu vector_irq[] table is indexed by CPU vector numbers, and each
>> entry contains an IRQ number.
>> Rename the special values VECTOR_UNDEFINED and VECTOR_RETRIGGERED to
>> IRQ_UNDEFINED and IRQ_RETRIGGERED to indicate that they are in the IRQ
>> number space, not the CPU vector number space.
> Makes some sense, but OTOH vector_irq actually reflects the vector
> state not the irq number state. The fact that we store the Linux irq
> number in vector_irq is just an implementation detail.
> VECTOR_UNDEFINED is certainly a misnomer; that should be VECTOR_UNUSED
> VECTOR_RETRIGGERED is pretty accurate. In the case we retrigger an
> interrupt, we merily use the Linux irq number to figure out which
> vector to kick. And after we retriggered it, we lose the association
> to the Linux irq number completely.
> That said, I'm working on storing the irq descriptor pointer in
> vector_irq instead of the irq number, which has the advantage that we
> avoid the lookup of the irq descriptor in the interrupt hotpath.

OK, I'll abandon this.  Thanks for taking a look!


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