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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, mingo@elte.hu,
	laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
	niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org,
	Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
	eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com,
	sbw@mit.edu, patches@linaro.org,
	"Paul E. McKenney" <paul.mckenney@linaro.org>
Subject: Re: [PATCH] trace: Don't declare trace_*_rcuidle functions in modules
Date: Wed, 5 Sep 2012 09:36:01 -0700	[thread overview]
Message-ID: <20120905163601.GD3308@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120905062306.GA14756@leaf>

On Tue, Sep 04, 2012 at 11:23:06PM -0700, Josh Triplett wrote:
> Tracepoints declare a static inline trace_*_rcuidle variant of the trace
> function, to support safely generating trace events from the idle loop.
> Module code never actually uses that variant of trace functions, because
> modules don't run code that needs tracing with RCU idled.  However, the
> declaration of those otherwise unused functions causes the module to
> reference rcu_idle_exit and rcu_idle_enter, which RCU does not export to
> modules.
> 
> To avoid this, don't generate trace_*_rcuidle functions for tracepoints
> declared in module code.
> 
> Reported-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Josh Triplett <josh@joshtriplett.org>

Looks good to me, please let me know when I should remove the exports.
Sending the relevant patch is sufficient notification.  ;-)

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

							Thanx, Paul

> ---
> On Tue, Sep 04, 2012 at 07:46:42PM -0400, Steven Rostedt wrote:
> > We could add either. Probably keep the ugliness of tracepoints inside
> > the tracepoint code than to start spreading it around to rcu. RCU has
> > its own ugliness features ;-)
> > 
> > Hence, I would be OK if you send me a patch that does what you proposed
> > and removes the EXPORT from RCU.
> 
>  include/linux/tracepoint.h |   28 ++++++++++++++++++----------
>  1 file changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> index 802de56..2f322c3 100644
> --- a/include/linux/tracepoint.h
> +++ b/include/linux/tracepoint.h
> @@ -136,6 +136,22 @@ static inline void tracepoint_synchronize_unregister(void)
>  		postrcu;						\
>  	} while (0)
> 
> +#ifndef MODULE
> +#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)	\
> +	static inline void trace_##name##_rcuidle(proto)		\
> +	{								\
> +		if (static_key_false(&__tracepoint_##name.key))		\
> +			__DO_TRACE(&__tracepoint_##name,		\
> +				TP_PROTO(data_proto),			\
> +				TP_ARGS(data_args),			\
> +				TP_CONDITION(cond),			\
> +				rcu_idle_exit(),			\
> +				rcu_idle_enter());			\
> +	}
> +#else
> +#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
> +#endif
> +
>  /*
>   * Make sure the alignment of the structure in the __tracepoints section will
>   * not add unwanted padding between the beginning of the section and the
> @@ -151,16 +167,8 @@ static inline void tracepoint_synchronize_unregister(void)
>  				TP_ARGS(data_args),			\
>  				TP_CONDITION(cond),,);			\
>  	}								\
> -	static inline void trace_##name##_rcuidle(proto)		\
> -	{								\
> -		if (static_key_false(&__tracepoint_##name.key))		\
> -			__DO_TRACE(&__tracepoint_##name,		\
> -				TP_PROTO(data_proto),			\
> -				TP_ARGS(data_args),			\
> -				TP_CONDITION(cond),			\
> -				rcu_idle_exit(),			\
> -				rcu_idle_enter());			\
> -	}								\
> +	__DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args),		\
> +		PARAMS(cond), PARAMS(data_proto), PARAMS(data_args))	\
>  	static inline int						\
>  	register_trace_##name(void (*probe)(data_proto), void *data)	\
>  	{								\
> -- 
> 1.7.10.4
> 


  parent reply	other threads:[~2012-09-05 16:38 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-30 18:56 [PATCH tip/core/rcu 0/15] Miscellaneous fixes Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 01/15] rcu: Add PROVE_RCU_DELAY to provoke difficult races Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 02/15] rcu: Pull TINY_RCU dyntick-idle tracing into non-idle region Paul E. McKenney
2012-08-31 16:53     ` Josh Triplett
2012-08-30 18:56   ` [PATCH tip/core/rcu 03/15] rcu: Properly initialize ->boost_tasks on CPU offline Paul E. McKenney
2012-08-31 17:56     ` Josh Triplett
2012-09-06 14:40     ` Peter Zijlstra
2012-09-06 20:58       ` Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 04/15] rcu: Permit RCU_NONIDLE() to be used from interrupt context Paul E. McKenney
2012-08-31 18:00     ` Josh Triplett
2012-09-04 22:33       ` Paul E. McKenney
2012-09-04 22:48         ` Josh Triplett
2012-09-04 22:51         ` Steven Rostedt
2012-09-04 23:08           ` Josh Triplett
2012-09-04 23:23             ` Steven Rostedt
2012-09-04 23:33               ` Josh Triplett
2012-09-04 23:43                 ` Paul E. McKenney
2012-09-06 18:54                   ` Josh Triplett
2012-09-06 19:54                     ` Steven Rostedt
2012-09-07  6:09                       ` Josh Triplett
2012-09-07 14:24                         ` Paul E. McKenney
2012-09-07 14:47                           ` Josh Triplett
2012-09-07 15:16                             ` Steven Rostedt
2012-09-12  1:07                               ` Paul E. McKenney
2012-09-12 14:13                                 ` Steven Rostedt
2012-09-12 15:03                                   ` Paul E. McKenney
2012-09-12 15:18                                     ` Steven Rostedt
2012-09-12 16:57                                       ` Paul E. McKenney
2012-09-04 23:46                 ` Steven Rostedt
2012-09-05  0:42                   ` Josh Triplett
2012-09-05  6:23                   ` [PATCH] trace: Don't declare trace_*_rcuidle functions in modules Josh Triplett
2012-09-05 14:26                     ` Mathieu Desnoyers
2012-09-05 16:36                     ` Paul E. McKenney [this message]
2012-09-06 19:49                     ` Steven Rostedt
2012-09-14  6:07                     ` [tip:core/rcu] trace: Don' t " tip-bot for Josh Triplett
2012-09-04 23:14           ` [PATCH tip/core/rcu 04/15] rcu: Permit RCU_NONIDLE() to be used from interrupt context Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 05/15] rcu: Improve boost selection when moving tasks to root rcu_node Paul E. McKenney
2012-08-31 18:09     ` Josh Triplett
2012-08-30 18:56   ` [PATCH tip/core/rcu 06/15] rcu: Make offline-CPU checking allow for indefinite delays Paul E. McKenney
2012-08-31 18:12     ` Josh Triplett
2012-08-30 18:56   ` [PATCH tip/core/rcu 07/15] rcu: Fix obsolete rcu_initiate_boost() header comment Paul E. McKenney
2012-08-31 18:13     ` Josh Triplett
2012-08-30 18:56   ` [PATCH tip/core/rcu 08/15] rcu: Apply for_each_rcu_flavor() to increment_cpu_stall_ticks() Paul E. McKenney
2012-08-31 18:15     ` Josh Triplett
2012-09-04 22:44       ` Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 09/15] rcu: Avoid rcu_print_detail_task_stall_rnp() segfault Paul E. McKenney
2012-08-31 18:19     ` Josh Triplett
2012-09-04 22:46       ` Paul E. McKenney
2012-09-04 22:55         ` Josh Triplett
2012-08-30 18:56   ` [PATCH tip/core/rcu 10/15] rcu: Protect rcu_node accesses during CPU stall warnings Paul E. McKenney
2012-08-31 18:23     ` Josh Triplett
2012-09-04 22:51       ` Paul E. McKenney
2012-09-06 14:51     ` Peter Zijlstra
2012-09-06 21:01       ` Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 11/15] rcu: Avoid spurious RCU " Paul E. McKenney
2012-08-31 18:24     ` Josh Triplett
2012-09-06 14:56     ` Peter Zijlstra
2012-09-06 15:07       ` Steven Rostedt
2012-09-06 15:19         ` Peter Zijlstra
2012-09-06 21:03           ` Paul E. McKenney
2012-09-06 21:41             ` Steven Rostedt
2012-09-06 21:58               ` Paul E. McKenney
2012-09-06 22:05                 ` Steven Rostedt
2012-09-06 22:22                   ` Paul E. McKenney
2012-09-07  7:00                     ` Peter Zijlstra
2012-09-07 14:42                       ` Steven Rostedt
2012-08-30 18:56   ` [PATCH tip/core/rcu 12/15] rcu: Remove redundant memory barrier from __call_rcu() Paul E. McKenney
2012-08-31 18:30     ` Josh Triplett
2012-08-31 18:40       ` Josh Triplett
2012-08-30 18:56   ` [PATCH tip/core/rcu 13/15] rcu: Move TINY_PREEMPT_RCU away from raw_local_irq_save() Paul E. McKenney
2012-08-31 18:34     ` Josh Triplett
2012-09-04 23:03       ` Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 14/15] time: RCU permitted to stop idle entry via softirq Paul E. McKenney
2012-08-31 18:51     ` Josh Triplett
2012-09-06 15:12     ` Peter Zijlstra
2012-09-06 21:35       ` Paul E. McKenney
2012-09-06 21:57         ` Steven Rostedt
2012-09-06 22:11           ` Paul E. McKenney
2012-08-30 18:56   ` [PATCH tip/core/rcu 15/15] kmemleak: Replace list_for_each_continue_rcu with new interface Paul E. McKenney
2012-08-31 18:55     ` Josh Triplett
2012-09-04 23:41       ` Paul E. McKenney
2012-08-31 16:49   ` [PATCH tip/core/rcu 01/15] rcu: Add PROVE_RCU_DELAY to provoke difficult races Josh Triplett
2012-09-04 22:36     ` Paul E. McKenney
2012-09-06 14:38   ` Peter Zijlstra
2012-09-06 20:51     ` Paul E. McKenney
2012-09-07  6:54       ` Peter Zijlstra

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