Re: Subject: [PATCH 1/2] x86: get back 15 vectors

From: Yinghai Lu
Date: Mon Jan 04 2010 - 13:42:37 EST


On 01/04/2010 08:18 AM, Eric W. Biederman wrote:
> Yinghai Lu <yinghai@xxxxxxxxxx> writes:
>
> This patch is wrong.
>
>> between FIRST_EXTERNAL_VECTOR (0x20) and FIRST_DEVICE_VECTOR (0x41)
>>
>> for 0x20 and 0x2f, we are safe be used_vectors will prevent it to use used one.
>
> We can not use any of 0x20 - 0x2f for ioapic irqs. We need the entire
> priority level to ensure that the irq move cleanup ipi is of a lower
> priority.
>
>> also try to reuse 0x30 to 0x3f after smp_affinity for irq[0,15] is changed to other cpu.
>
> There may be a point with 0x30 to 0x3f as I recall when those irqs come through a legacy
> pic we need to reserve those vectors on all cpus.

ok, I see.

any reason that we can not use 0x40?

Thanks

Yinghai
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