From c63b7682b6d90530d3a071ff75b81bfddcce8598 Mon Sep 17 00:00:00 2001 From: Tal Shorer Date: Sat, 1 Aug 2015 15:27:57 +0300 Subject: tracing: Allow disabling compilation of specific trace systems Allow a trace events header file to disable compilation of its trace events by defining the preprocessor macro NOTRACE. This could be done, for example, according to a Kconfig option. Link: http://lkml.kernel.org/r/1438432079-11704-3-git-send-email-tal.shorer@gmail.com Signed-off-by: Tal Shorer Signed-off-by: Steven Rostedt --- include/linux/tracepoint.h | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'include/linux/tracepoint.h') diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index a5f7f3ecafa3..afada369c5b7 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -111,7 +111,18 @@ extern void syscall_unregfunc(void); #define TP_ARGS(args...) args #define TP_CONDITION(args...) args -#ifdef CONFIG_TRACEPOINTS +/* + * Individual subsystem my have a separate configuration to + * enable their tracepoints. By default, this file will create + * the tracepoints if CONFIG_TRACEPOINT is defined. If a subsystem + * wants to be able to disable its tracepoints from being created + * it can define NOTRACE before including the tracepoint headers. + */ +#if defined(CONFIG_TRACEPOINTS) && !defined(NOTRACE) +#define TRACEPOINTS_ENABLED +#endif + +#ifdef TRACEPOINTS_ENABLED /* * it_func[0] is never NULL because there is at least one element in the array @@ -234,7 +245,7 @@ extern void syscall_unregfunc(void); #define EXPORT_TRACEPOINT_SYMBOL(name) \ EXPORT_SYMBOL(__tracepoint_##name) -#else /* !CONFIG_TRACEPOINTS */ +#else /* !TRACEPOINTS_ENABLED */ #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ static inline void trace_##name(proto) \ { } \ @@ -266,7 +277,7 @@ extern void syscall_unregfunc(void); #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) #define EXPORT_TRACEPOINT_SYMBOL(name) -#endif /* CONFIG_TRACEPOINTS */ +#endif /* TRACEPOINTS_ENABLED */ #ifdef CONFIG_TRACING /** -- cgit v1.2.2 From 7904b5c4988e18b50056b5e71a3ffca752a8a451 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 22 Sep 2015 17:13:19 -0400 Subject: tracepoint: Give priority to probes of tracepoints In order to guarantee that a probe will be called before other probes that are attached to a tracepoint, there needs to be a mechanism to provide priority of one probe over the others. Adding a prio field to the struct tracepoint_func, which lets the probes be sorted by the priority set in the structure. If no priority is specified, then a priority of 10 is given (this is a macro, and perhaps may be changed in the future). Now probes may be added to affect other probes that are attached to a tracepoint with a guaranteed order. One use case would be to allow tracing of tracepoints be able to filter by pid. A special (higher priority probe) may be added to the sched_switch tracepoint and set the necessary flags of the other tracepoints to notify them if they should be traced or not. In case a tracepoint is enabled at the sched_switch tracepoint too, the order of the two are not random. Cc: Mathieu Desnoyers Signed-off-by: Steven Rostedt --- include/linux/tracepoint.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux/tracepoint.h') diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index afada369c5b7..6b79537a42b1 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -26,6 +26,7 @@ struct notifier_block; struct tracepoint_func { void *func; void *data; + int prio; }; struct tracepoint { @@ -42,9 +43,14 @@ struct trace_enum_map { unsigned long enum_value; }; +#define TRACEPOINT_DEFAULT_PRIO 10 + extern int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data); extern int +tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data, + int prio); +extern int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data); extern void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv), @@ -207,6 +213,13 @@ extern void syscall_unregfunc(void); (void *)probe, data); \ } \ static inline int \ + register_trace_prio_##name(void (*probe)(data_proto), void *data,\ + int prio) \ + { \ + return tracepoint_probe_register_prio(&__tracepoint_##name, \ + (void *)probe, data, prio); \ + } \ + static inline int \ unregister_trace_##name(void (*probe)(data_proto), void *data) \ { \ return tracepoint_probe_unregister(&__tracepoint_##name,\ -- cgit v1.2.2 From a15920bea0428cd22291637f6c72542b1843e65f Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 2 Nov 2015 17:42:42 -0500 Subject: tracepoints: Fix documentation of RCU lockdep checks The documentation on top of __DECLARE_TRACE() does not match its implementation since the condition check has been added to the RCU lockdep checks. Update the documentation to match its implementation. Link: http://lkml.kernel.org/r/1446504164-21563-1-git-send-email-mathieu.desnoyers@efficios.com CC: Dave Hansen Fixes: a05d59a56733 "tracing: Add condition check to RCU lockdep checks" Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt --- include/linux/tracepoint.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux/tracepoint.h') diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 6b79537a42b1..696a339c592c 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -184,10 +184,11 @@ extern void syscall_unregfunc(void); * structure. Force alignment to the same alignment as the section start. * * When lockdep is enabled, we make sure to always do the RCU portions of - * the tracepoint code, regardless of whether tracing is on or we match the - * condition. This lets us find RCU issues triggered with tracepoints even - * when this tracepoint is off. This code has no purpose other than poking - * RCU a bit. + * the tracepoint code, regardless of whether tracing is on. However, + * don't check if the condition is false, due to interaction with idle + * instrumentation. This lets us find RCU issues triggered with tracepoints + * even when this tracepoint is off. This code has no purpose other than + * poking RCU a bit. */ #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ extern struct tracepoint __tracepoint_##name; \ -- cgit v1.2.2