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From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.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: Re: [PATCH 6/8] perf,tracing: Prepare the perf-trace interface for RCU changes
Date: Wed, 12 Feb 2020 09:26:55 -0500	[thread overview]
Message-ID: <20200212092655.4ba6cd79@gandalf.local.home> (raw)
In-Reply-To: <20200212094107.951346701@infradead.org>

On Wed, 12 Feb 2020 10:32:16 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> The tracepoint interface will stop providing regular RCU context; make
> sure we do it ourselves, since perf makes use of regular RCU protected
> data.
> 

Suggested-by: Steven Rostedt (VMware) <rosted@goodmis.org>

  ;-)

-- Steve

> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>  kernel/events/core.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -8950,6 +8950,7 @@ void perf_tp_event(u16 event_type, u64 c
>  {
>  	struct perf_sample_data data;
>  	struct perf_event *event;
> +	unsigned long rcu_flags;
>  
>  	struct perf_raw_record raw = {
>  		.frag = {
> @@ -8961,6 +8962,8 @@ void perf_tp_event(u16 event_type, u64 c
>  	perf_sample_data_init(&data, 0, 0);
>  	data.raw = &raw;
>  
> +	rcu_flags = trace_rcu_enter();
> +
>  	perf_trace_buf_update(record, event_type);
>  
>  	hlist_for_each_entry_rcu(event, head, hlist_entry) {
> @@ -8996,6 +8999,8 @@ void perf_tp_event(u16 event_type, u64 c
>  	}
>  
>  	perf_swevent_put_recursion_context(rctx);
> +
> +	trace_rcu_exit(rcu_flags);
>  }
>  EXPORT_SYMBOL_GPL(perf_tp_event);
>  
> 


  reply	other threads:[~2020-02-12 14:26 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 [this message]
2020-02-12 15:07     ` Mathieu Desnoyers
2020-02-12  9:32 ` [PATCH 7/8] tracing: Employ trace_rcu_{enter,exit}() Peter Zijlstra
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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