From acd388fd3af350ab24c6ab6f19b83fc4a4f3aa60 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 31 Mar 2015 14:37:12 -0400 Subject: tracing: Give system name a pointer Normally the compiler will use the same pointer for a string throughout the file. But there's no guarantee of that happening. Later changes will require that all events have the same pointer to the system string. Name the system string and have all events point to it. Testing this, it did not increases the size of the text, except for the notes section, which should not harm the real size any. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index c674ee8f7fca..62b8fac7ded5 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -202,7 +202,7 @@ enum trace_reg { struct ftrace_event_call; struct ftrace_event_class { - char *system; + const char *system; void *probe; #ifdef CONFIG_PERF_EVENTS void *perf_probe; -- cgit v1.2.3 From 0c564a538aa934ad15b2145aaf8b64f3feb0be63 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 24 Mar 2015 17:58:09 -0400 Subject: tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values Several tracepoints use the helper functions __print_symbolic() or __print_flags() and pass in enums that do the mapping between the binary data stored and the value to print. This works well for reading the ASCII trace files, but when the data is read via userspace tools such as perf and trace-cmd, the conversion of the binary value to a human string format is lost if an enum is used, as userspace does not have access to what the ENUM is. For example, the tracepoint trace_tlb_flush() has: __print_symbolic(REC->reason, { TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, { TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, { TLB_LOCAL_SHOOTDOWN, "local shootdown" }, { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }) Which maps the enum values to the strings they represent. But perf and trace-cmd do no know what value TLB_LOCAL_MM_SHOOTDOWN is, and would not be able to map it. With TRACE_DEFINE_ENUM(), developers can place these in the event header files and ftrace will convert the enums to their values: By adding: TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH); TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN); TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN); $ cat /sys/kernel/debug/tracing/events/tlb/tlb_flush/format [...] __print_symbolic(REC->reason, { 0, "flush on task switch" }, { 1, "remote shootdown" }, { 2, "local shootdown" }, { 3, "local mm shootdown" }) The above is what userspace expects to see, and tools do not need to be modified to parse them. Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Cc: Guilherme Cox Cc: Tony Luck Cc: Xie XiuQi Acked-by: Namhyung Kim Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 2 +- include/linux/tracepoint.h | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 62b8fac7ded5..112cf49d9576 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -285,7 +285,7 @@ struct ftrace_event_call { struct tracepoint *tp; }; struct trace_event event; - const char *print_fmt; + char *print_fmt; struct event_filter *filter; void *mod; void *data; diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index c72851328ca9..a5f7f3ecafa3 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -36,6 +36,12 @@ struct tracepoint { struct tracepoint_func __rcu *funcs; }; +struct trace_enum_map { + const char *system; + const char *enum_string; + unsigned long enum_value; +}; + extern int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data); extern int @@ -87,6 +93,8 @@ extern void syscall_unregfunc(void); #define PARAMS(args...) args +#define TRACE_DEFINE_ENUM(x) + #endif /* _LINUX_TRACEPOINT_H */ /* -- cgit v1.2.3 From 3673b8e4ce7237160fa31ee8d7e94a4d5a9976a1 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Mar 2015 15:44:21 -0400 Subject: tracing: Allow for modules to convert their enums to values Update the infrastructure such that modules that declare TRACE_DEFINE_ENUM() will have those enums converted into their values in the tracepoint print fmt strings. Link: http://lkml.kernel.org/r/87vbhjp74q.fsf@rustcorp.com.au Acked-by: Rusty Russell Reviewed-by: Masami Hiramatsu Tested-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/module.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/module.h b/include/linux/module.h index 42999fe2dbd0..53dc41dd5c62 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -338,6 +338,8 @@ struct module { #ifdef CONFIG_EVENT_TRACING struct ftrace_event_call **trace_events; unsigned int num_trace_events; + struct trace_enum_map **trace_enums; + unsigned int num_trace_enums; #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD unsigned int num_ftrace_callsites; -- cgit v1.2.3