On Mon, May 17, 2021 at 3:47 PM Thomas Gleixner [off-list ref] wrote:

Nitesh,

On Mon, May 17 2021 at 14:21, Nitesh Lal wrote:

quoted

On Mon, May 17, 2021 at 1:26 PM Robin Murphy [off-list ref] wrote:

We can use irq_set_affinity() to set the hint mask as well, however, maybe
there is a specific reason behind separating those two in the
first place (maybe not?).

Yes, because kernel side settings might overwrite the hint.

quoted

But even in this case, we have to either modify the PMU drivers' IRQs
affinity from the userspace or we will have to make changes in the existing
request_irq code path.

Adjusting them from user space does not work for various reasons,
especially CPU hotplug.

quoted

I am not sure about the latter because we already have the required controls
to adjust the device IRQ mask (by using default_smp_affinity or by modifying
them manually).

default_smp_affinity does not help at all and there is nothing a module
can modify manually.

Right, it will not help a module.

I'll send out a patch series which cleans that up soon.

Ack, thanks.

Thanks,

        tglx

--
Nitesh