Re: [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs

Alex Nixon
2008-08-19T19:01:35Z

Yinghai Lu wrote:
> On Tue, Aug 19, 2008 at 11:13 AM, Alex Nixon (Intern)
> <Alex.Nixon@citrix.com> wrote:
>> Yinghai Lu <yhlu.kernel@gmail.com> wrote:
>>> On Tue, Aug 19, 2008 at 9:55 AM, Alex Nixon <alex.nixon@citrix.com> wrote:
>>>> If the number of discovered IRQs is suspiciously low, this patch causes
>>>> the number reported to default to NR_IRQS, rather than 32. NR_IRQS has
>>>> already been defined to be a >sensible value for the current system (in
>>>> particular, at least 224 when paravirtualisation is involved).
>>>>
>>> if only one ioapic, nr will be 24<<1, you will get 48. Does pv has io apic
>>> ?
>>>
>>> YH
>>>
>> I'm not sure about the general case, but Xen does not (Jeremy correct me if
>> I'm wrong).
>>
>> Unless I'm missing something (which I may well be; I'm new to this area of
>> code), it seems more logical anyway to default back to the calculated
>> system-specific value (NR_IRQS), instead of 32, which seems rather
>> arbitrary.
>
> can you try !CONFIG_HAVE_SPARSE_IRQ and CONFIG_HAVE_SPARSE_IRQ ?
>
> YH

Sorry I should have mentioned originally - the bug occurs both with
CONFIG_HAVE_SPARSE_IRQ enabled, and disabled.

- Alex