Re: [PATCH] tracing, rcu: Hide trace event rcu_nocb_wake when not used

From: Paul E. McKenney
Date: Thu Oct 12 2017 - 18:44:50 EST


On Thu, Oct 12, 2017 at 06:16:41PM -0400, Steven Rostedt wrote:
> From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
>
> The trace event rcu_nocb_wake is only used when CONFIG_RCU_NOCB_CPU is
> defined. But the trace event is defined regardless. As defined trace
> events take up memory, it is a waste to have it defined when not used.
> Surround the trace event with an #ifdef to have it only defined when it
> is used.
>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

And this one applied cleanly, queued for review and testing, thank you!

Thanx, Paul

> ---
> Index: linux-trace.git/include/trace/events/rcu.h
> ===================================================================
> --- linux-trace.git.orig/include/trace/events/rcu.h
> +++ linux-trace.git/include/trace/events/rcu.h
> @@ -242,6 +242,7 @@ TRACE_EVENT(rcu_exp_funnel_lock,
> __entry->grphi, __entry->gpevent)
> );
>
> +#ifdef CONFIG_RCU_NOCB_CPU
> /*
> * Tracepoint for RCU no-CBs CPU callback handoffs. This event is intended
> * to assist debugging of these handoffs.
> @@ -284,6 +285,7 @@ TRACE_EVENT(rcu_nocb_wake,
>
> TP_printk("%s %d %s", __entry->rcuname, __entry->cpu, __entry->reason)
> );
> +#endif
>
> /*
> * Tracepoint for tasks blocking within preemptible-RCU read-side
>