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authorStefan Assmann <sassmann@redhat.com>2009-10-13 00:17:21 +0400
committerFrederic Weisbecker <fweisbec@gmail.com>2009-10-13 00:17:21 +0400
commit369bc18f9a6c4e2686204c1d7476ab684a720968 (patch)
tree84606ab4244907d10b60fb091f2d2e23024ebbae
parent3c355863fb32070a2800f41106519c5c3038623a (diff)
downloadlinux-369bc18f9a6c4e2686204c1d7476ab684a720968.tar.xz
ftrace: add kernel command line graph function filtering
Add a command line parameter to allow limiting the function graphs that are traced on boot up from the given top-level callers , when ftrace=function_graph is specified. This patch adds the following command line option: ftrace_graph_filter=function-list Where function-list is a comma separated list of functions to filter. [fweisbec@gmail.com: picked the documentation changes from the v2 patch] Signed-off-by: Stefan Assmann <sassmann@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4AD2DEB9.2@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
-rw-r--r--Documentation/kernel-parameters.txt7
-rw-r--r--kernel/trace/ftrace.c34
2 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6fa7292947e5..1dc4b9cc20e5 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -778,6 +778,13 @@ and is between 256 and 4096 characters. It is defined in the file
by the set_ftrace_notrace file in the debugfs
tracing directory.
+ ftrace_graph_filter=[function-list]
+ [FTRACE] Limit the top level callers functions traced
+ by the function graph tracer at boot up.
+ function-list is a comma separated list of functions
+ that can be changed at run time by the
+ set_graph_function 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 9a72853a8f0a..91283d40821e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -78,6 +78,10 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+#endif
+
static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_ops *op = ftrace_list;
@@ -2248,6 +2252,7 @@ void ftrace_set_notrace(unsigned char *buf, int len, int reset)
#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
static int __init set_ftrace_notrace(char *str)
{
@@ -2263,6 +2268,31 @@ static int __init set_ftrace_filter(char *str)
}
__setup("ftrace_filter=", set_ftrace_filter);
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int __init set_graph_function(char *str)
+{
+ strncpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
+ return 1;
+}
+__setup("ftrace_graph_filter=", set_graph_function);
+
+static void __init set_ftrace_early_graph(char *buf)
+{
+ int ret;
+ char *func;
+
+ while (buf) {
+ func = strsep(&buf, ",");
+ /* we allow only one expression at a time */
+ ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
+ func);
+ if (ret)
+ printk(KERN_DEBUG "ftrace: function %s not "
+ "traceable\n", func);
+ }
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
static void __init set_ftrace_early_filter(char *buf, int enable)
{
char *func;
@@ -2279,6 +2309,10 @@ static void __init set_ftrace_early_filters(void)
set_ftrace_early_filter(ftrace_filter_buf, 1);
if (ftrace_notrace_buf[0])
set_ftrace_early_filter(ftrace_notrace_buf, 0);
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ if (ftrace_graph_buf[0])
+ set_ftrace_early_graph(ftrace_graph_buf);
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
}
static int