diff options
| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2014-12-12 22:27:10 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2014-12-15 10:17:38 -0500 |
| commit | 0daa2302968c13b657118d6ac92471f8fd2f3f28 (patch) | |
| tree | 8bea68f7bbeab6521c11c01f55b5660082eeedf6 /include/linux/ftrace.h | |
| parent | 5f893b2639b21ffe6834b1aebba392c37d2b83f9 (diff) | |
tracing: Add tp_printk cmdline to have tracepoints go to printk()
Add the kernel command line tp_printk option that will have tracepoints
that are active sent to printk() as well as to the trace buffer.
Passing "tp_printk" will activate this. To turn it off, the sysctl
/proc/sys/kernel/tracepoint_printk can have '0' echoed into it. Note,
this only works if the cmdline option is used. Echoing 1 into the sysctl
file without the cmdline option will have no affect.
Note, this is a dangerous option. Having high frequency tracepoints send
their data to printk() can possibly cause a live lock. This is another
reason why this is only active if the command line option is used.
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1412121539300.16494@nanos
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ftrace.h')
| -rw-r--r-- | include/linux/ftrace.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index f4bc14b7d444..1da602982cf9 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -879,6 +879,7 @@ static inline int test_tsk_trace_graph(struct task_struct *tsk) enum ftrace_dump_mode; extern enum ftrace_dump_mode ftrace_dump_on_oops; +extern int tracepoint_printk; extern void disable_trace_on_warning(void); extern int __disable_trace_on_warning; |