Re: [PATCH 17/22 -v7] mcount tracer for wakeup latency timings.

Peter Zijlstra
2008-01-30T09:37:26Z

On Tue, 2008-01-29 at 22:15 -0500, Steven Rostedt wrote:

> +static void notrace __wakeup_reset(struct tracing_trace *tr)
> +{
> + struct tracing_trace_cpu *data;
> + int cpu;
> +
> + assert_spin_locked(&wakeup_lock);
> +
> + for_each_possible_cpu(cpu) {
> + data = tr->data[cpu];
> + tracing_reset(data);
> + }
> +
> + wakeup_cpu = -1;
> + wakeup_prio = -1;
> + if (wakeup_task) {
> + put_task_struct(wakeup_task);
> + tracing_stop_function_trace();
> + }
> +
> + wakeup_task = NULL;
> +
> + /*
> + * Don't let the trace_enabled = 1 show up before
> + * the wakeup_task is reset.
> + */
> + smp_wmb();
> +}

Another un-balanced barrier.