From 2fbb90db1b8fcc78f43830f1a009f3af243c5f42 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 7 Feb 2012 09:32:43 -0500 Subject: [PATCH] tracing/rcu: Add trace_##name##__rcuidle() static tracepoint for inside rcu_idle_exit() sections Added is a new static inline function that lets *any* tracepoint be used inside a rcu_idle_exit() section. And this also solves the problem where the same tracepoint may be used inside a rcu_idle_exit() section as well as outside of one. I added a new tracepoint function with a "_rcuidle" extension. All tracepoints can be used with either the normal "trace_foobar()" function, or the "trace_foobar_rcuidle()" function when inside a rcu_idle_exit() section. All tracepoints defined by TRACE_EVENT() or any of the derivatives will have a "_rcuidle()" function also defined. When a tracepoint is used within an rcu_idle_exit() section, the "_rcuidle()" version must be used. This denotes that the tracepoint is within rcu_idle_exit() and it allows the rcu read locks within the tracepoint to still be valid, as this version takes us out of rcu_idle_exit(). Another nice aspect about this patch is that "static inline"s are not compiled into text when not used. So only the tracepoints that actually use the _rcuidle() version will have them defined in the actual text that is booted. Link: http://lkml.kernel.org/r/1328563113.2200.39.camel@gandalf.stny.rr.com> Acked-by: Paul E. McKenney Reviewed-by: Josh Triplett Signed-off-by: Steven Rostedt --- include/linux/tracepoint.h | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index df0a779..fc36da9 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -114,7 +114,7 @@ static inline void tracepoint_synchronize_unregister(void) * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto". */ -#define __DO_TRACE(tp, proto, args, cond) \ +#define __DO_TRACE(tp, proto, args, cond, prercu, postrcu) \ do { \ struct tracepoint_func *it_func_ptr; \ void *it_func; \ @@ -122,6 +122,7 @@ static inline void tracepoint_synchronize_unregister(void) \ if (!(cond)) \ return; \ + prercu; \ rcu_read_lock_sched_notrace(); \ it_func_ptr = rcu_dereference_sched((tp)->funcs); \ if (it_func_ptr) { \ @@ -132,6 +133,7 @@ static inline void tracepoint_synchronize_unregister(void) } while ((++it_func_ptr)->func); \ } \ rcu_read_unlock_sched_notrace(); \ + postrcu; \ } while (0) /* @@ -139,7 +141,7 @@ static inline void tracepoint_synchronize_unregister(void) * not add unwanted padding between the beginning of the section and the * structure. Force alignment to the same alignment as the section start. */ -#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ +#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ extern struct tracepoint __tracepoint_##name; \ static inline void trace_##name(proto) \ { \ @@ -147,7 +149,17 @@ static inline void tracepoint_synchronize_unregister(void) __DO_TRACE(&__tracepoint_##name, \ TP_PROTO(data_proto), \ TP_ARGS(data_args), \ - TP_CONDITION(cond)); \ + TP_CONDITION(cond),,); \ + } \ + static inline void trace_##name##_rcuidle(proto) \ + { \ + if (static_branch(&__tracepoint_##name.key)) \ + __DO_TRACE(&__tracepoint_##name, \ + TP_PROTO(data_proto), \ + TP_ARGS(data_args), \ + TP_CONDITION(cond), \ + rcu_idle_exit(), \ + rcu_idle_enter()); \ } \ static inline int \ register_trace_##name(void (*probe)(data_proto), void *data) \ @@ -190,9 +202,11 @@ static inline void tracepoint_synchronize_unregister(void) EXPORT_SYMBOL(__tracepoint_##name) #else /* !CONFIG_TRACEPOINTS */ -#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ +#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ static inline void trace_##name(proto) \ { } \ + static inline void trace_##name##_rcuidle(proto) \ + { } \ static inline int \ register_trace_##name(void (*probe)(data_proto), \ void *data) \ -- 2.7.4