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    Subject[for-next][PATCH 18/21] tracing: Add ftrace_graph_notrace boot parameter
    From: Namhyung Kim <namhyung@kernel.org>

    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.

    Link: http://lkml.kernel.org/p/1402590233-22321-2-git-send-email-namhyung@kernel.org

    Signed-off-by: Namhyung Kim <namhyung@kernel.org>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.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 c1b9aa8c5a52..19c0a9096a02 100644
    --- a/Documentation/kernel-parameters.txt
    +++ b/Documentation/kernel-parameters.txt
    @@ -1097,6 +1097,12 @@ 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 232b898eebbd..17885a27281c 100644
    --- a/kernel/trace/ftrace.c
    +++ b/kernel/trace/ftrace.c
    @@ -3884,6 +3884,7 @@ __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)
    @@ -3893,16 +3894,29 @@ 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);
    @@ -3931,7 +3945,9 @@ 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 */
    }

    --
    2.0.0



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