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Date:   Tue, 17 Jul 2018 20:25:28 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Joel Fernandes <joel@joelfernandes.org>
Cc:     linux-kernel@vger.kernel.org, kernel-team@android.com,
        Boqun Feng <boqun.feng@gmail.com>,
        Byungchul Park <byungchul.park@lge.com>,
        Erick Reyes <erickreyes@google.com>,
        Ingo Molnar <mingo@redhat.com>,
        Julia Cartwright <julia@ni.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Paul McKenney <paulmck@linux.vnet.ibm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Glexiner <tglx@linutronix.de>,
        Todd Kjos <tkjos@google.com>,
        Tom Zanussi <tom.zanussi@linux.intel.com>,
        Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v10 2/3] tracepoint: Make rcuidle tracepoint callers use
 SRCU
Message-ID: <20180717182528.GK2494@hirez.programming.kicks-ass.net>
References: <20180713215547.255620-1-joel@joelfernandes.org>
 <20180713215547.255620-3-joel@joelfernandes.org>
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On Fri, Jul 13, 2018 at 02:55:46PM -0700, Joel Fernandes wrote:
> +		/* keep srcu and sched-rcu usage consistent */		\
> +		preempt_disable_notrace();				\
> +									\
> +		/*							\
> +		 * For rcuidle callers, use srcu since sched-rcu	\
> +		 * doesn't work from the idle path.			\
> +		 */							\
> +		if (rcuidle)						\
> +			idx = srcu_read_lock_notrace(&tracepoint_srcu);	\
> +		else							\
> +			rcu_read_lock_sched_notrace();			\

That else is completely superfluous. rcu_read_lock_sched_notrace() :=
prempt_disable_notrace().