Re: [PATCH 07/14] genirq: Add a new generic IPI reservation code to irq core

Qais Yousef
2015-11-09T10:12:11Z

On 11/07/2015 01:31 PM, Thomas Gleixner wrote:
> On Tue, 3 Nov 2015, Qais Yousef wrote:
>> +
>> + /* always allocate a virq per cpu */
>> + nr_irqs = ipi_mask_weight(dest);
> That's not really a good assumption. Not all architectures need
> seperate interrupt numbers / descriptors because they can allocate
> from a per cpu interrupt space. We really want to handle that here as
> well. So we need a flag in the IPI domain which tells us whether that
> allocation needs to be weight(desc) or 1.

OK. But is it bad to always allocate the weight? I thought allocating
virqs is cheap, or maybe not?

Thanks,
Qais