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 /kernel/trace/trace.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 'kernel/trace/trace.h')
| -rw-r--r-- | kernel/trace/trace.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index c138c149d6ef..8de48bac1ce2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1313,5 +1313,6 @@ void trace_event_init(void); static inline void __init trace_event_init(void) { } #endif +extern struct trace_iterator *tracepoint_print_iter; #endif /* _LINUX_KERNEL_TRACE_H */ |