Re: [PATCH v2 9/9] perf,tracing: Allow function tracing when !RCU

Kim Phillips
2020-02-14T20:38:19Z

On 2/12/20 3:01 PM, Peter Zijlstra wrote:
> Since perf is now able to deal with !rcu_is_watching() contexts,
> remove the restraint.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> kernel/trace/trace_event_perf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/kernel/trace/trace_event_perf.c
> +++ b/kernel/trace/trace_event_perf.c
> @@ -477,7 +477,7 @@ static int perf_ftrace_function_register
> {
> struct ftrace_ops *ops = &event->ftrace_ops;
>
> - ops->flags = FTRACE_OPS_FL_RCU;
> + ops->flags = 0;
> ops->func = perf_ftrace_function_call;
> ops->private = (void *)(unsigned long)nr_cpu_ids;

If this is the last user of the flag, should all remaining
FTRACE_OPS_FL_RCU references be removed, too?

Thanks,

Kim