linux-kernel - [PATCH v2 8/9] tracing: Remove regular RCU context for

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Message-Id: <20200212210750.255616631@infradead.org>
Date:   Wed, 12 Feb 2020 22:01:47 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        rostedt@...dmis.org
Cc:     peterz@...radead.org, mingo@...nel.org, joel@...lfernandes.org,
        gregkh@...uxfoundation.org, gustavo@...eddedor.com,
        tglx@...utronix.de, paulmck@...nel.org, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com
Subject: [PATCH v2 8/9] tracing: Remove regular RCU context for _rcuidle tracepoints (again)

Effectively revert commit 865e63b04e9b2 ("tracing: Add back in
rcu_irq_enter/exit_irqson() for rcuidle tracepoints") now that we've
taught perf how to deal with not having an RCU context provided.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 include/linux/tracepoint.h |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -179,10 +179,8 @@ static inline struct tracepoint *tracepo
 		 * For rcuidle callers, use srcu since sched-rcu	\
 		 * doesn't work from the idle path.			\
 		 */							\
-		if (rcuidle) {						\
+		if (rcuidle)						\
 			__idx = srcu_read_lock_notrace(&tracepoint_srcu);\
-			rcu_irq_enter_irqsave();			\
-		}							\
 									\
 		it_func_ptr = rcu_dereference_raw((tp)->funcs);		\
 									\
@@ -194,10 +192,8 @@ static inline struct tracepoint *tracepo
 			} while ((++it_func_ptr)->func);		\
 		}							\
 									\
-		if (rcuidle) {						\
-			rcu_irq_exit_irqsave();				\
+		if (rcuidle)						\
 			srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\
-		}							\
 									\
 		preempt_enable_notrace();				\
 	} while (0)