Messages in this thread | | | Date | Mon, 11 Jan 2010 14:57:14 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [patch] x86, apic: use 0x20 for the IRQ_MOVE_CLEANUP_VECTOR instead of 0x1f |
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On 01/11/2010 02:53 PM, Suresh Siddha wrote: > >> However, my most serious concern with this patch is that there is a >> fairly significant change due to this patch, which is that the legacy >> IRQ vectors now fall *inside* the FIRST_DEVICE_VECTOR range. This isn't >> a bad thing -- in fact, it is fundamentally the right thing to do >> especially once we consider platforms which *don't* have the legacy IRQs >> -- but it makes me scared of unexpected behavior changes as a result. >> If you feel confident that that is not the case, could you outline why >> it shouldn't be a problem? > > In irqinit.c, we statically pre-assign the per-cpu vector to irq > mappings (vector_irq) for all the legacy IRQ vectors. Similarly irq_cfg > is statically initialized for legacy IRQ's in io_apic.c. So we won't be > able to use this space for anything else. >
What enforces that, though? The used_vector bitmap? In the past it was enforced simply by being < FIRST_DEVICE_VECTOR.
-hpa
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