Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> writes:
> +static void etm_event_destroy(struct perf_event *event)
> +{
> + /* switching off the source will also tear down the path */
> + etm_event_power_sources(event->cpu, false);
> +}
> +
> +static int etm_event_init(struct perf_event *event)
> +{
> + int ret;
> +
> + if (event->attr.type != etm_pmu.type)
> + return -ENOENT;
> +
> + if (event->cpu >= nr_cpu_ids)
> + return -EINVAL;
> +
> + /* only one session at a time */
> + if (etm_event_source_enabled(event->cpu))
> + return -EBUSY;
Why is this the case? If you were to configure the event in pmu::add()
and deconfigure it in pmu::del(), like you already do with the buffer
part, you could handle as many sessions as you want.
> +
> + /*
> + * Make sure CPUs don't disappear between the
> + * power up sequence and configuration.
> + */
> + get_online_cpus();
> + ret = etm_event_power_sources(event->cpu, true);
> + if (ret)
> + goto out;
> +
> + ret = etm_event_config_sources(event->cpu);
This can be done in pmu::add(), if you can call directly into
etm_configure_cpu() or etm_config_enable() so that there's no cross-cpu
calling in between.
> +
> + event->destroy = etm_event_destroy;
> +out:
> + put_online_cpus();
> + return ret;
> +}
> +
> static int __init etm_perf_init(void)
> {
> etm_pmu.capabilities = PERF_PMU_CAP_EXCLUSIVE;
> @@ -59,6 +234,7 @@ static int __init etm_perf_init(void)
> etm_pmu.attr_groups = etm_pmu_attr_groups;
> etm_pmu.task_ctx_nr = perf_sw_context;
> etm_pmu.read = etm_event_read;
> + etm_pmu.event_init = etm_event_init;
>
> return perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
> }
One general comment -- it would be slightly easier at least for me if
all the pmu related bits were in one patch.
Thanks,
--
Alex
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