Re: [RFC Part2 v1 03/21] x86, irq: Save destination CPU ID in irq_cfg

[Jiang Liu <jiang.liu@linux.intel.com>]

On 2014/9/17 1:47, Thomas Gleixner wrote:
> 
> 
> On Thu, 11 Sep 2014, Jiang Liu wrote:
> 
>> Cache destination CPU APIC ID into struct irq_cfg when assigning vector
>> for interrupt. Upper layer just needs to read the cached APIC ID instead
>> of calling apic->cpu_mask_to_apicid_and(), it helps to hide APIC driver
>> details from IOAPIC/HPET/MSI drivers..
>>
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>> ---
>>  arch/x86/include/asm/hw_irq.h |    1 +
>>  arch/x86/kernel/apic/vector.c |    4 ++++
>>  2 files changed, 5 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
>> index 7624fffc2822..3d51d74d6c01 100644
>> --- a/arch/x86/include/asm/hw_irq.h
>> +++ b/arch/x86/include/asm/hw_irq.h
>> @@ -116,6 +116,7 @@ struct irq_data;
>>  struct irq_cfg {
>>  	cpumask_var_t		domain;
>>  	cpumask_var_t		old_domain;
>> +	unsigned int		dest_apicid;
>>  	u8			vector;
>>  	u8			move_in_progress : 1;
>>  #ifdef CONFIG_IRQ_REMAP
>> diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
>> index 7562cb15b3bd..287ae4e8d500 100644
>> --- a/arch/x86/kernel/apic/vector.c
>> +++ b/arch/x86/kernel/apic/vector.c
>> @@ -188,6 +188,10 @@ next:
>>  	}
>>  	free_cpumask_var(tmp_mask);
> 
> Lacks a comment what this call is actually doing.
How about this?
/* cache destination APIC IDs into cfg->dest_apicid */
Regards!
Gerry
>   
>> +	if (!err)
>> +		err = apic->cpu_mask_to_apicid_and(mask, cfg->domain,
>> +						   &cfg->dest_apicid);
>> +
> 
> Thanks,
> 
> 	tglx
>