Mathieu Poirier <[email protected]> writes:
> +static void etm_event_destroy(struct perf_event *event) {}
> +
> +static int etm_event_init(struct perf_event *event)
> +{
> + if (event->attr.type != etm_pmu.type)
> + return -ENOENT;
> +
> + if (event->cpu >= nr_cpu_ids)
> + return -EINVAL;
> +
> + event->destroy = etm_event_destroy;
You don't have to do this if it's a nop, event::destroy can be NULL.
> +
> + return 0;
> +}
> +static void *alloc_event_data(int cpu)
> +{
> + int lcpu, size;
> + cpumask_t *mask;
> + struct etm_cpu_data *cpu_data;
> + struct etm_event_data *event_data;
> +
> + /* First get memory for the session's data */
> + event_data = kzalloc(sizeof(struct etm_event_data), GFP_KERNEL);
> + if (!event_data)
Looks like a whitespace mixup.
> + return NULL;
> +
> + /* Make sure nothing disappears under us */
> + get_online_cpus();
> + size = num_online_cpus();
> +
> + mask = &event_data->mask;
> + if (cpu != -1)
> + cpumask_set_cpu(cpu, mask);
> + else
> + cpumask_copy(mask, cpu_online_mask);
It would be nice to have a comment somewhere here explaining that you
have to set up tracer on each cpu in case of per-thread counter and
why. We must have discussed this, but I forgot already.
Btw, do you want to also set 'size' to 1 for cpu != -1 case?
> + put_online_cpus();
> +
> + /* Allocate an array of cpu_data to work with */
> + event_data->cpu_data = kcalloc(size,
> + sizeof(struct etm_cpu_data *),
> + GFP_KERNEL);
> + if (!event_data->cpu_data)
> + goto free_event_data;
> +
> + /* Allocate a cpu_data for each CPU this event is dealing with */
> + for_each_cpu(lcpu, mask) {
> + cpu_data = kzalloc(sizeof(struct etm_cpu_data), GFP_KERNEL);
> + if (!cpu_data)
> + goto free_event_data;
> +
> + event_data->cpu_data[lcpu] = cpu_data;
> + }
Wouldn't it be easier to allocate the whole thing with one
event_data->cpu_data = kcalloc(size, sizeof(struct etm_cpu_data), GFP_KERNEL);
?
Regards,
--
Alex
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