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From: Josh Triplett <josh@joshtriplett.org>
To: Steven Rostedt <rostedt@goodmis.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, 4 Sep 2012 17:42:49 -0700	[thread overview]
Message-ID: <20120905004248.GA12373@jtriplet-mobl1> (raw)
In-Reply-To: <1346802402.27919.44.camel@gandalf.local.home>

On Tue, Sep 04, 2012 at 07:46:42PM -0400, Steven Rostedt wrote:
> 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)

Yeah, I've had the adventure of hand-tracing through most of those in
the past myself. :)  At least they have a fairly clear hierarchy,
without particularly complex conditionals.

Ah, for a language with decent code generation facilities. :)

> > 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.

To clarify: does what I proposed as in the macro change to avoid
defining trace_*_rcuidle in modules, or makes the change to define panicy
versions of the two functions trace_*_rcuidle needs?

- Josh Triplett

  reply	other threads:[~2012-09-05  0:43 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 [this message]
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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