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    Subject[PATCH 5.2 082/131] fgraph: Remove redundant ftrace_graph_notrace_addr() test
    Date
    From: Changbin Du <changbin.du@gmail.com>

    commit 6c77221df96177da0520847ce91e33f539fb8b2d upstream.

    We already have tested it before. The second one should be removed.
    With this change, the performance should have little improvement.

    Link: http://lkml.kernel.org/r/20190730140850.7927-1-changbin.du@gmail.com

    Cc: stable@vger.kernel.org
    Fixes: 9cd2992f2d6c ("fgraph: Have set_graph_notrace only affect function_graph tracer")
    Signed-off-by: Changbin Du <changbin.du@gmail.com>
    Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    kernel/trace/trace_functions_graph.c | 17 +++++++----------
    1 file changed, 7 insertions(+), 10 deletions(-)

    --- a/kernel/trace/trace_functions_graph.c
    +++ b/kernel/trace/trace_functions_graph.c
    @@ -137,6 +137,13 @@ int trace_graph_entry(struct ftrace_grap
    if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
    return 0;

    + /*
    + * Do not trace a function if it's filtered by set_graph_notrace.
    + * Make the index of ret stack negative to indicate that it should
    + * ignore further functions. But it needs its own ret stack entry
    + * to recover the original index in order to continue tracing after
    + * returning from the function.
    + */
    if (ftrace_graph_notrace_addr(trace->func)) {
    trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
    /*
    @@ -156,16 +163,6 @@ int trace_graph_entry(struct ftrace_grap
    return 0;

    /*
    - * Do not trace a function if it's filtered by set_graph_notrace.
    - * Make the index of ret stack negative to indicate that it should
    - * ignore further functions. But it needs its own ret stack entry
    - * to recover the original index in order to continue tracing after
    - * returning from the function.
    - */
    - if (ftrace_graph_notrace_addr(trace->func))
    - return 1;
    -
    - /*
    * Stop here if tracing_threshold is set. We only write function return
    * events to the ring buffer.
    */

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