Re: [PATCH RESEND] x86/fixup_irq: Clean the offlining CPU from theirq affinity mask

From: Srivatsa S. Bhat
Date: Wed Sep 26 2012 - 05:03:13 EST


On 09/26/2012 02:26 PM, Liu, Chuansheng wrote:
>> A return value of 0 and 1 are acceptable. So this check isn't correct.
>>
>> Regards,
>> Srivatsa S. Bhat
>>
> Which case value 1 is acceptable, could you share? Thanks.

I can see the following in include/linux/irq.h:

/*
* Return value for chip->irq_set_affinity()
*
* IRQ_SET_MASK_OK - OK, core updates irq_data.affinity
* IRQ_SET_MASK_NOCPY - OK, chip did update irq_data.affinity
*/
enum {
IRQ_SET_MASK_OK = 0,
IRQ_SET_MASK_OK_NOCOPY,
};

And see some of those ->irq_set_affinity() implementations at various
places.

Regards,
Srivatsa S. Bhat

>
>> OMG, why did you drop the other hunk which cleared the cpu *before*
>> invoking ->irq_set_affinity()? IMO, altering irq affinity involves more work
>> than just altering the mask; that's why you have that ->irq_set_affinity()
>> function. So, if you alter the mask *after* calling ->irq_set_affinity(),
>> its not right..
> Sorry the mistake, will update.
>

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