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Message-ID: <491CAD20.9020202@kernel.org>
Date: Thu, 13 Nov 2008 14:41:36 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
CC: mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
linux-kernel@...r.kernel.org, travis@....com
Subject: Re: [PATCH] sparse_irq aka dyn_irq v13
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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