From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>
Subject: Re: [PATCH v2] tracing/perf: Move rcu_irq_enter/exit_irqson() to perf trace point hook
Date: Tue, 11 Feb 2020 11:18:28 -0500 [thread overview]
Message-ID: <20200211111828.48058768@gandalf.local.home> (raw)
In-Reply-To: <20200211153452.GW14914@hirez.programming.kicks-ass.net>
On Tue, 11 Feb 2020 16:34:52 +0100
Peter Zijlstra <peterz@infradead.org> wrote:
> > + if (unlikely(in_nmi()))
> > + goto out;
>
> unless I'm mistaken, we can simply do rcu_nmi_enter() in this case, and
> rcu_nmi_exit() on the other end.
>
> > + rcu_irq_enter_irqson();
The thing is, I don't think this can ever happen. We've had in the
tracepoint.h:
/* srcu can't be used from NMI */ \
WARN_ON_ONCE(rcuidle && in_nmi()); \
And this has yet to trigger.
-- Steve
next prev parent reply other threads:[~2020-02-11 16:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 14:50 [PATCH v2] tracing/perf: Move rcu_irq_enter/exit_irqson() to perf trace point hook Steven Rostedt
2020-02-11 15:34 ` Mathieu Desnoyers
2020-02-11 15:46 ` Peter Zijlstra
2020-02-11 16:02 ` Mathieu Desnoyers
2020-02-11 15:34 ` Peter Zijlstra
2020-02-11 16:18 ` Steven Rostedt [this message]
2020-02-11 16:27 ` Mathieu Desnoyers
2020-02-11 16:35 ` Steven Rostedt
2020-02-11 17:29 ` Peter Zijlstra
2020-02-11 17:32 ` Peter Zijlstra
2020-02-11 18:54 ` Paul E. McKenney
2020-02-12 8:05 ` Peter Zijlstra
2020-02-12 9:05 ` Paul E. McKenney
2020-02-11 17:35 ` Mathieu Desnoyers
2020-02-12 8:02 ` Peter Zijlstra
2020-02-12 15:14 ` Mathieu Desnoyers
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