Messages in this thread | | | Date | Wed, 24 Nov 2010 14:53:14 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [question] NR_IRQS in genirq |
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On Wed, 24 Nov 2010, Haojian Zhuang wrote: > On Wed, Nov 24, 2010 at 9:18 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > > Why can nr_irqs become larger? Is that a theoretical problem or did > > you run into this ? > > My hardware environment is ARM. Each machine description can specify > nr_irqs. In my implementation of PXA, NR_IRQS is fixed for SoC > internal IRQs. And there's some additional board IRQs, we arrange them > between NR_IRQS and nr_irqs. So nr_irqs will be larger than NR_IRQS if > board IRQs exists.
And that's wrong. NR_IRQS is the upper bound. nr_irqs is the runtime bound which is supposed to be <= NR_IRQS.
The whole point of sparse_irq is that it does not statically allocate irq_desc[NR_IRQS] to reduce memory consumption if only a small number of irqs are actuallt used by a specific board.
Thanks,
tglx
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