Re: [PATCH v4 4/7] arm_pmu: Tidy up clear_event_idx call backs

[Suzuki K Poulose]

On 03/07/18 13:49, Mark Rutland wrote:
> On Mon, Jul 02, 2018 at 10:59:45PM +0100, Suzuki K Poulose wrote:
> > The armpmu uses get_event_idx callback to allocate an event
> > counter for a given event, which marks the selected counter
> > as "used". Now, when we delete the counter, the arm_pmu goes
> > ahead and clears the "used" bit and then invokes the "clear_event_idx"
> > call back, which kind of splits the job between the core code
> > and the backend. To keep things tidy, mandate the implementation
> > of clear_event_idx() and add it for exisiting backends.
> > This will be useful for adding the chained event support, where
> > we leave the event idx maintenance to the backend.
> >
> > Also, when an event is removed from the PMU, reset the hw.idx
> > to indicate that a counter is not allocated for this event,
> > to help the backends do better checks. This will be also used
> > for the chain counter support.
> >
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Cc: Will Deacon <will.deacon@xxxxxxx>
> > Reviewed-by: Julien Thierry <julien.thierry@xxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > ---
> > Changes since v3:
> >   - Add clear_event_idx call back for backends.
> > ---
> >   arch/arm/kernel/perf_event_v6.c | 8 ++++++++
> >   arch/arm/kernel/perf_event_v7.c | 9 +++++++++
> >   arch/arm64/kernel/perf_event.c  | 7 +++++++
> >   drivers/perf/arm_pmu.c          | 7 +++----
> >   4 files changed, 27 insertions(+), 4 deletions(-)
>
> I beleive this is missing the xscale PMU code.

Ah! Thanks for spotting. I will fix that.
> Otherwiwse, this looks good to me.

Thanks
Suzuki