Re: [PATCH RFC] tracepoint: Introduce tracepoint callbacks executing with preempt on

From: Steven Rostedt <rostedt@goodmis.org>
To: Joel Fernandes <joelaf@google.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zilstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Tom Zanussi <tom.zanussi@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Thomas Glexiner <tglx@linutronix.de>,
	Boqun Feng <boqun.feng@gmail.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Fenguang Wu <fengguang.wu@intel.com>,
	Baohong Liu <baohong.liu@intel.com>,
	Vedang Patel <vedang.patel@intel.com>,
	"Cc: Android Kernel" <kernel-team@android.com>
Subject: Re: [PATCH RFC] tracepoint: Introduce tracepoint callbacks executing with preempt on
Date: Fri, 27 Apr 2018 12:22:01 -0400	[thread overview]
Message-ID: <20180427122201.75abc313@gandalf.local.home> (raw)
In-Reply-To: <CAJWu+or9GJwkDK9+842YbobG3=xVW-PgqS=uE5P2xFbDhmqxEQ@mail.gmail.com>

On Fri, 27 Apr 2018 09:14:30 -0700
Joel Fernandes <joelaf@google.com> wrote:

> > Hmmm...  Do I need to create a _notrace variant of srcu_read_lock()
> > and srcu_read_unlock()?  
> 
> That shouldn't be needed. For the rcu_read_lock_sched case, there is a
> preempt_disable which needs to be a notrace, but for the srcu one,
> since we don't do that, I think it should be fine.

Actually, I think I may agree here too. Because the _notrace is for
function tracing, and it shouldn't affect it. If people don't want it
traced, they could add those functions to the list in the notrace file.

-- Steve