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From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	rostedt@goodmis.org
Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org,
	gregkh@linuxfoundation.org, gustavo@embeddedor.com,
	tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org,
	mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com
Subject: [PATCH 7/8] tracing: Employ trace_rcu_{enter,exit}()
Date: Wed, 12 Feb 2020 10:32:17 +0100	[thread overview]
Message-ID: <20200212094108.007700525@infradead.org> (raw)
In-Reply-To: <20200212093210.468391728@infradead.org>

Replace the opencoded (and incomplete) RCU manipulations with the new
helpers to ensure a regular RCU context when calling into
__ftrace_trace_stack().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/trace/trace.c |   19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2989,24 +2989,11 @@ void __trace_stack(struct trace_array *t
 		   int pc)
 {
 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+	unsigned long rcu_flags;
 
-	if (rcu_is_watching()) {
-		__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
-		return;
-	}
-
-	/*
-	 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
-	 * but if the above rcu_is_watching() failed, then the NMI
-	 * triggered someplace critical, and rcu_irq_enter() should
-	 * not be called from NMI.
-	 */
-	if (unlikely(in_nmi()))
-		return;
-
-	rcu_irq_enter_irqsave();
+	rcu_flags = trace_rcu_enter();
 	__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
-	rcu_irq_exit_irqsave();
+	trace_rcu_exit(rcu_flags);
 }
 
 /**



  parent reply	other threads:[~2020-02-12  9:43 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12  9:32 [PATCH 0/8] tracing vs rcu vs nmi Peter Zijlstra
2020-02-12  9:32 ` [PATCH 1/8] rcu: Rename rcu_irq_{enter,exit}_irqson() Peter Zijlstra
2020-02-12  9:32 ` [PATCH 2/8] rcu: Mark rcu_dynticks_curr_cpu_in_eqs() inline Peter Zijlstra
2020-02-12  9:32 ` [PATCH 3/8] rcu,tracing: Create trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-12  9:32 ` [PATCH 4/8] sched,rcu,tracing: Mark preempt_count_{add,sub}() notrace Peter Zijlstra
2020-02-12 14:24   ` Steven Rostedt
2020-02-12 15:02     ` Peter Zijlstra
2020-02-12 15:14       ` Steven Rostedt
2020-02-12 15:38         ` Peter Zijlstra
2020-02-12  9:32 ` [PATCH 5/8] x86,tracing: Mark debug_stack_{set_zero,reset)() notrace Peter Zijlstra
2020-02-12 14:25   ` Steven Rostedt
2020-02-12 15:04     ` Peter Zijlstra
2020-02-12 15:18       ` Steven Rostedt
2020-02-12 15:39         ` Peter Zijlstra
2020-02-12  9:32 ` [PATCH 6/8] perf,tracing: Prepare the perf-trace interface for RCU changes Peter Zijlstra
2020-02-12 14:26   ` Steven Rostedt
2020-02-12 15:07     ` Mathieu Desnoyers
2020-02-12  9:32 ` Peter Zijlstra [this message]
2020-02-12  9:32 ` [PATCH 8/8] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Peter Zijlstra
2020-02-12 14:29   ` Steven Rostedt
2020-02-12 15:12     ` Peter Zijlstra
2020-02-12 10:01 ` [PATCH 0/8] tracing vs rcu vs nmi Peter Zijlstra
2020-02-12 10:56   ` Will Deacon
2020-02-12 11:58     ` Peter Zijlstra
2020-02-12 14:32     ` Steven Rostedt
2020-02-12 15:21       ` Peter Zijlstra
2020-02-12 10:03 ` Peter Zijlstra
2020-02-12 10:07 ` Peter Zijlstra
2020-02-12 10:09 ` Peter Zijlstra

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