From 41c52c0db9607e59f90da7da5309489fa06e887f Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 22 May 2008 11:46:33 -0400 Subject: ftrace: set_ftrace_notrace feature While debugging latencies in the RT kernel, I found that it would be nice to be able to filter away functions from the trace than just to filter on functions. I added a new interface to the debugfs tracing directory called set_ftrace_notrace When dynamic frace is enabled, this lets you filter away functions that will not be recorded in the trace. It is similar to adding 'notrace' to those functions but by doing it without recompiling the kernel. Here's how set_ftrace_filter and set_ftrace_notrace interact. Remember, if set_ftrace_filter is set, it removes all functions from the trace execpt for those listed in the set_ftrace_filter. set_ftrace_notrace will prevent those functions from being traced. If you were to set one function in both set_ftrace_filter and set_ftrace_notrace and that function was the same, then you would end up with an empty trace. the set of functions to trace is: set_ftrace_filter == empty then all functions not in set_ftrace_notrace else set of the set_ftrace_filter and not in set of set_ftrace_notrace. Signed-off-by: Steven Rostedt Signed-off-by: Thomas Gleixner --- include/linux/ftrace.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/ftrace.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 922e23d0196f..ffbbd54a720e 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -48,6 +48,7 @@ enum { FTRACE_FL_FAILED = (1 << 1), FTRACE_FL_FILTER = (1 << 2), FTRACE_FL_ENABLED = (1 << 3), + FTRACE_FL_NOTRACE = (1 << 4), }; struct dyn_ftrace { -- cgit v1.2.2