The architecture specific code will determine whether the IRQ could be migrated
in process context. For example, the IRQ_MOVE_PCNTXT flag will be set on x86
systems if interrupt remapping is enabled.
On 03/26/2012 10:28 PM, Bjorn Helgaas wrote:
> [This is not really a PCI question, so +cc Thomas, LKML.]
>
> On Mon, Mar 26, 2012 at 3:06 AM, Yevgeny Petrilin
> <yevgenyp@xxxxxxxxxxxxxx> wrote:
>> Hello,
>>
>> I'm working on an issue where affinity changes to IRQ only have effect after the first interrupt which still happens on the original core.
>> I understand that the decision regarding it takes place in this code:
>>
>> if (irq_can_move_pcntxt(data)) {
>> ret = chip->irq_set_affinity(data, mask, false);
>> switch (ret) {
>> case IRQ_SET_MASK_OK:
>> cpumask_copy(data->affinity, mask);
>> case IRQ_SET_MASK_OK_NOCOPY:
>> irq_set_thread_affinity(desc);
>> ret = 0;
>> }
>> } else {
>> irqd_set_move_pending(data);
>> irq_copy_pending(desc, mask);
>> }
>>
>> Which means that the "IRQD_MOVE_PCNTXT" flag is not set in irq_data->state_use_accessors.
>> I was able to add this flag using irq_modify_status(), which is probably not the way to go.
>> This option also doesn't exist in older kernels (2.6.32)
>>
>> So the question is, when irq_desc is created, how is it determined that "IRQD_MOVE_PCNTXT" flag is set?
>>
>> Thanks,
>> Yevgeny
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