Peter Zijlstra <pet...@infradead.org> writes:
> + /*
> + * perf_event_attr::disabled events will not run and can be initialized
> + * without IPI. Except when this is the first event for the context, in
> + * that case we need the magic of the IPI to set ctx->is_active.
> + *
> + * The IOC_ENABLE that is sure to follow the creation of a disabled
> + * event will issue the IPI and reprogram the hardware.
> + */
> + if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
> ctx->nr_events) {
> + raw_spin_lock_irq(&ctx->lock);
> + if (task && ctx->task == TASK_TOMBSTONE) {
Confused: isn't that redundant? If ctx->task reads TASK_TOMBSTONE, task
is always !NULL, afaict. And in any case, if a task context is going
away, we shouldn't probably be adding events there. Or am I missing
something?
Other than that, this makes sense to me, fwiw.
Regards,
--
Alex
