Re: [PATCH] sparse_irq aka dyn_irq v13

[Yinghai Lu]

Andrew Morton wrote:

>> ...
>>
>>>> +static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
>>> Do these need to be 32-bit?  Maybe they'll fit in 16-bit, dunno.
>>>
>> struct irq_desc {
>>         unsigned int            irq;
>> #ifdef CONFIG_SPARSE_IRQ
>>         struct list_head        list;
>>         struct list_head        hash_entry;
>>         struct timer_rand_state *timer_rand_state;
>>         unsigned int            *kstat_irqs;
> 
> That doesn't address my question.
> 
> The above array can be very large.  Can we halve its size by using
> 16-bit quantities?  Will this code ever encounter IRQ numbers larger
> than 65536?
> 

NR_CPUS=4096, NR_IRQS_LEGACY=16, and that array will be 256k bytes

later could change that alloc_bootmem, so NR_CPUS will be replaced to nr_cpu_ids

YH
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