Re: [PATCH] x86, sparseirq: let nr_irqs equal to NR_IRQS

From: Yinghai Lu
Date: Tue Dec 28 2010 - 16:25:08 EST


On Tue, Dec 28, 2010 at 9:42 AM, Konrad Rzeszutek Wilk
<konrad.wilk@xxxxxxxxxx> wrote:
> On Mon, Dec 27, 2010 at 04:54:11PM -0800, Yinghai Lu wrote:
>>
>>
>> For x86_64 system:
>> when we have 128 cpus with 5 ioapics, will have nr_irqs = 3064
>>       120 + 8 * 128 + 120 * 16
>> systems could take 20 pcie,  when intel 10g are used with
>> sriov and ixgbevf, every vf will need 3 irqs, and one device
>> have 64 vf. so will need 20 * 3 * 64 = 3840.
>> some 6 ports Intel 10gb may need more.
>>
>> Just remove that function for x86, and let nr_irqs to NR_IRQS
>> because We already have radix-tree and bit_map for searching desc for irq.
>
> Won't that make the arch_probe_nr_irqs be NR_IRQS_LEGACY?

int nr_irqs = NR_IRQS;

and

int __init __weak arch_probe_nr_irqs(void)
{
return NR_IRQS_LEGACY;
}

int __init early_irq_init(void)
{
int i, initcnt, node = first_online_node;
struct irq_desc *desc;

init_irq_default_affinity();

/* Let arch update nr_irqs and return the nr of preallocated irqs */
initcnt = arch_probe_nr_irqs();
printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS,
nr_irqs, initcnt);


that arch_probe_nr_irqs() is return for initcnt...

should change nr_irqs in the functions...

some confusing...


>
> I am looking at Linus's today tree, or is this patch based on some other tree?
>
>>
>> Notes: long before same vresion cause one of Ingo's setup udev hang...
>>
>> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>>
>> ---
>>  arch/x86/kernel/apic/io_apic.c |   22 ----------------------
>>  1 file changed, 22 deletions(-)
>>
>> Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
>> ===================================================================
>> --- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
>> +++ linux-2.6/arch/x86/kernel/apic/io_apic.c
>> @@ -3637,28 +3637,6 @@ int get_nr_irqs_gsi(void)
>>       return nr_irqs_gsi;
>>  }
>>
>> -#ifdef CONFIG_SPARSE_IRQ
>> -int __init arch_probe_nr_irqs(void)
>> -{
>> -     int nr;
>> -
>> -     if (nr_irqs > (NR_VECTORS * nr_cpu_ids))
>> -             nr_irqs = NR_VECTORS * nr_cpu_ids;
>> -
>> -     nr = nr_irqs_gsi + 8 * nr_cpu_ids;
>> -#if defined(CONFIG_PCI_MSI) || defined(CONFIG_HT_IRQ)
>> -     /*
>> -      * for MSI and HT dyn irq
>> -      */
>> -     nr += nr_irqs_gsi * 16;
>> -#endif
>> -     if (nr < nr_irqs)
>> -             nr_irqs = nr;
>> -
>> -     return NR_IRQS_LEGACY;
>> -}
>> -#endif
>> -
>>  static int __io_apic_set_pci_routing(struct device *dev, int irq,
>>                               struct io_apic_irq_attr *irq_attr)
>>  {
>> --
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