[PATCH V1] perf: qcom: Add L3 cache PMU driver

[Peter Zijlstra]

On Mon, Mar 21, 2016 at 10:35:08AM +0000, Mark Rutland wrote:
> > +static
> > +int qcom_l3_cache__event_add(struct perf_event *event, int flags)
> > +{
> > +	struct l3cache_pmu *system = to_l3cache_pmu(event->pmu);
> > +	struct hw_perf_event *hwc = &event->hw;
> > +	int idx;
> > +	int prev_cpu;
> > +	int err = 0;
> > +
> > +	/*
> > +	 * We need to disable the pmu while adding the event, otherwise
> > +	 * the perf tick might kick-in and re-add this event.
> > +	 */
> > +	perf_pmu_disable(event->pmu);

Why did you write that? If you really need this you did something
seriously wrong elsewhere, because:

kernel/events/core.c:event_sched_in() is the only place calling
pmu::add() and that explicitly already does this.