[PATCH v3 1/4] irq: export kstat_irqs

[Thomas Gleixner]

On Sun, Dec 06 2020 at 09:40, James Bottomley wrote:
> On Sun, 2020-12-06 at 17:40 +0100, Thomas Gleixner wrote:
>> On Sat, Dec 05 2020 at 12:39, Jarkko Sakkinen wrote:
>> > On Fri, Dec 04, 2020 at 06:43:37PM -0700, Jerry Snitselaar wrote:
>> > > To try and detect potential interrupt storms that
>> > > have been occurring with tpm_tis devices it was suggested
>> > > to use kstat_irqs() to get the number of interrupts.
>> > > Since tpm_tis can be built as a module it needs kstat_irqs
>> > > exported.
>> > 
>> > I think you should also have a paragraph explicitly stating that
>> > i915_pmu.c contains a duplicate of kstat_irqs() because it is not
>> > exported as of today. It adds a lot more weight to this given that
>> > there is already existing mainline usage (kind of).
>> 
>> It's abusage and just the fact that it exists is not an argument by
>> itself.
>
> What we want is a count of the interrupts to see if we're having an
> interrupt storm from the TPM device (some seem to be wired to fire the
> interrupt even when there's no event to warrant it).  Since
> kstat_irqs_user() does the correct RCU locking, should we be using that
> instead?

If we need to export it, yes. But I still have to understand the
value. See my other reply.

Thanks,

        tglx