Messages in this thread | | | Date | Wed, 11 May 2022 17:09:24 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH v6 01/29] irq/matrix: Expose functions to allocate the best CPU for new vectors |
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On Fri, May 06, 2022 at 09:48:28PM +0200, Thomas Gleixner wrote: > Ricardo,
Thank you very much for your feedback Thomas! I am sorry for my late reply, I had been out of office.
> > On Thu, May 05 2022 at 16:59, Ricardo Neri wrote: > > Certain types of interrupts, such as NMI, do not have an associated vector. > > They, however, target specific CPUs. Thus, when assigning the destination > > CPU, it is beneficial to select the one with the lowest number of > > vectors. > > Why is that beneficial especially in the context of a NMI watchdog which > then broadcasts the NMI to all other CPUs?
My intent was not the NMI watchdog specifically but potential use cases that do not involve NMI broadcasts. If the NMI targets a single CPU, it is best to select the CPU with the lowest vector allocation count.
> > That's wishful thinking perhaps, but I don't see any benefit at all. > > > Prepend the functions matrix_find_best_cpu_managed() and > > matrix_find_best_cpu_managed() > > The same function prepended twice becomes two functions :) >
Sorry, I missed this.
> > with the irq_ prefix and expose them for > > IRQ controllers to use when allocating and activating vector-less IRQs. > > There is no such thing like a vectorless IRQ. NMIs have a vector. Can we > please describe facts and not pulled out of thin air concepts which do > not exist?
Thank you for the clarification. I see your point. I wrote this patch because maskable interrupts and NMIs have different entry points. As you state, however, the also have a vector.
I can drop this patch.
BR, Ricardo
> > Thanks, > > tglx
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