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    Subject[PATCH v2 2/4] ring-buffer: rename debugfs file tracing_on to writing_enabled
    From: Steven Rostedt <>

    Impact: clean up

    The debugfs file name tracing_on is confusing since there is also
    a tracing_enabled. When a tracer is added to current_tracer and
    tracing_enabled is set to 1, then the tracer will start tracing.
    The current file tracing_on, if set to 1, will allow writing to
    the ring buffers. If tracing_on is set to 0 then the ring buffers
    are read only, and any attempt by the tracers to write to the
    ring buffers will fail.

    But the name tracing_on confuses both developers and users.
    This patch renames it to 'writing_enabled'. This is exactly what
    the file does. When set to 1, the ring buffers have writing enabled
    and when set to 0, the ring buffers can not be written to.

    The tracers do not get any call backs called or other notification
    that the ring buffers have been set to read only, except when they
    attempt to write to the ring buffers, that write will fail.

    Note: it is a requirement that any tracer that uses the ring buffers
    must handle a failure to write to the ring buffers, since the ring buffers
    may be disabled for any number of reasons.

    Signed-off-by: Steven Rostedt <>
    kernel/trace/ring_buffer.c | 5 +++--
    1 files changed, 3 insertions(+), 2 deletions(-)

    diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
    index a9d9760..dba6876 100644
    --- a/kernel/trace/ring_buffer.c
    +++ b/kernel/trace/ring_buffer.c
    @@ -2514,10 +2514,11 @@ static __init int rb_init_debugfs(void)

    d_tracer = tracing_init_dentry();

    - entry = debugfs_create_file("tracing_on", 0644, d_tracer,
    + entry = debugfs_create_file("writing_enabled", 0644, d_tracer,
    &ring_buffer_flags, &rb_simple_fops);
    if (!entry)
    - pr_warning("Could not create debugfs 'tracing_on' entry\n");
    + pr_warning("Could not create debugfs"
    + " 'writing_enabled' entry\n");

    return 0;

     \ /
      Last update: 2009-01-07 05:21    [W:0.019 / U:12.324 seconds]
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