From 369bc18f9a6c4e2686204c1d7476ab684a720968 Mon Sep 17 00:00:00 2001 From: Stefan Assmann Date: Mon, 12 Oct 2009 22:17:21 +0200 Subject: [PATCH] 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 Acked-by: Steven Rostedt LKML-Reference: <4AD2DEB9.2@redhat.com> Signed-off-by: Frederic Weisbecker --- Documentation/kernel-parameters.txt | 7 ++++++ kernel/trace/ftrace.c | 34 +++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) 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 -- 2.30.2