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From: Steven Rostedt <rostedt@goodmis.org>
To: Josh Triplett <josh@joshtriplett.org>
Cc: paulmck@linux.vnet.ibm.com, 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 tip/core/rcu 04/15] rcu: Permit RCU_NONIDLE() to be used from interrupt context
Date: Tue, 04 Sep 2012 19:46:42 -0400	[thread overview]
Message-ID: <1346802402.27919.44.camel@gandalf.local.home> (raw)
In-Reply-To: <20120904233344.GB11855@jtriplet-mobl1>

On Tue, 2012-09-04 at 16:33 -0700, Josh Triplett wrote:
>  
> > > +#ifdef 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
> > > +
> > 
> > Egad! More macros on top of macros! Yeah I know I'm the most guilty of
> > this, but it just seems to add one more indirection that I would like to
> > avoid.
> 
> This doesn't seem to add a significant amount of complexity; it forwards
> exactly the same parameters to the helper macro, and just moves the one
> function definition there and makes it conditional.  This still seems
> more preferable than exporting functions just so they won't get called.

The change itself is not complex. But what is already there is complex
enough. I'm talking more about adding to:

$ grep '#define' include/linux/tracepoint.h
#define _LINUX_TRACEPOINT_H
#define PARAMS(args...) args
#define TP_PROTO(args...)       args
#define TP_ARGS(args...)        args
#define TP_CONDITION(args...)   args
#define __DO_TRACE(tp, proto, args, cond, prercu, postrcu)              \
#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
#define DEFINE_TRACE_FN(name, reg, unreg)                                \
#define DEFINE_TRACE(name)                                              \
#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)                              \
#define EXPORT_TRACEPOINT_SYMBOL(name)                                  \
#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
#define DEFINE_TRACE_FN(name, reg, unreg)
#define DEFINE_TRACE(name)
#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
#define EXPORT_TRACEPOINT_SYMBOL(name)
#define DECLARE_TRACE_NOARGS(name)                                      \
#define DECLARE_TRACE(name, proto, args)                                \
#define DECLARE_TRACE_CONDITION(name, proto, args, cond)                \
#define TRACE_EVENT_FLAGS(event, flag)
#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
#define DEFINE_EVENT(template, name, proto, args)               \
#define DEFINE_EVENT_PRINT(template, name, proto, args, print)  \
#define DEFINE_EVENT_CONDITION(template, name, proto,           \
#define TRACE_EVENT(name, proto, args, struct, assign, print)   \
#define TRACE_EVENT_FN(name, proto, args, struct,               \
#define TRACE_EVENT_CONDITION(name, proto, args, cond,          \
#define TRACE_EVENT_FLAGS(event, flag)


> 
> I could live with that; it seems preferable to unnecessary exports,
> though it still seems much uglier to me than the conditional definition
> of trace_*_rcuidle. :)

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.

-- Steve



  parent reply	other threads:[~2012-09-04 23:46 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 [this message]
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
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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