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Subject[PATCH 1/4] tracing: Add ftrace_graph_notrace boot parameter
Date
The ftrace_graph_notrace option is for specifying notrace filter for
function graph tracer at boot time. It can be altered after boot
using set_graph_notrace file on the debugfs.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
Documentation/kernel-parameters.txt | 6 ++++++
kernel/trace/ftrace.c | 24 ++++++++++++++++++++----
2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 43842177b771..40cf0caf92a9 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1062,6 +1062,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
that can be changed at run time by the
set_graph_function file in the debugfs tracing directory.

+ ftrace_graph_notrace=[function-list]
+ [FTRACE] Do not trace from the functions specified in
+ function-list. This list is a comma separated list of
+ functions that can be changed at run time by the
+ set_graph_notrace file in the debugfs tracing directory.
+
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 071908f58e7a..f08edd7125c6 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3628,6 +3628,7 @@ __setup("ftrace_filter=", set_ftrace_filter);

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);

static int __init set_graph_function(char *str)
@@ -3637,16 +3638,29 @@ static int __init set_graph_function(char *str)
}
__setup("ftrace_graph_filter=", set_graph_function);

-static void __init set_ftrace_early_graph(char *buf)
+static int __init set_graph_notrace_function(char *str)
+{
+ strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+ return 1;
+}
+__setup("ftrace_graph_notrace=", set_graph_notrace_function);
+
+static void __init set_ftrace_early_graph(char *buf, int enable)
{
int ret;
char *func;
+ unsigned long *table = ftrace_graph_funcs;
+ int *count = &ftrace_graph_count;
+
+ if (!enable) {
+ table = ftrace_graph_notrace_funcs;
+ count = &ftrace_graph_notrace_count;
+ }

while (buf) {
func = strsep(&buf, ",");
/* we allow only one expression at a time */
- ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
- FTRACE_GRAPH_MAX_FUNCS, func);
+ ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
if (ret)
printk(KERN_DEBUG "ftrace: function %s not "
"traceable\n", func);
@@ -3675,7 +3689,9 @@ static void __init set_ftrace_early_filters(void)
ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (ftrace_graph_buf[0])
- set_ftrace_early_graph(ftrace_graph_buf);
+ set_ftrace_early_graph(ftrace_graph_buf, 1);
+ if (ftrace_graph_notrace_buf[0])
+ set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
}

--
1.7.9.2


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