From: Tom Zanussi <tom.zanu...@linux.intel.com>

It would be useful to have a cheat-sheet for everything under
tracing/events/ alongside the existing text describing the other files
in the tracing/ dir.

Add short descriptions of the directories and files under events/
along with examples, similar to the existing text for the other files
in tracing/.

Also clean up a few minor alignment problems noticed when adding the
new text.

Link: http://lkml.kernel.org/r/1389993104.3040.445.camel@empanada

Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
 kernel/trace/trace.c | 37 ++++++++++++++++++++++++++++++++++---
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 20c755e..2ced5e5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3523,9 +3523,9 @@ static const char readme_msg[] =
 #ifdef CONFIG_DYNAMIC_FTRACE
        "\n  available_filter_functions - list of functions that can be 
filtered on\n"
        "  set_ftrace_filter\t- echo function name in here to only trace these 
functions\n"
-       "            accepts: func_full_name, *func_end, func_begin*, 
*func_middle*\n"
-       "            modules: Can select a group via module\n"
-       "             Format: :mod:<module-name>\n"
+       "             accepts: func_full_name, *func_end, func_begin*, 
*func_middle*\n"
+       "             modules: Can select a group via module\n"
+       "              Format: :mod:<module-name>\n"
        "             example: echo :mod:ext3 > set_ftrace_filter\n"
        "            triggers: a command to perform when function is hit\n"
        "              Format: <function>:<trigger>[:count]\n"
@@ -3573,6 +3573,37 @@ static const char readme_msg[] =
        "  stack_trace_filter\t- Like set_ftrace_filter but limits what 
stack_trace traces\n"
 #endif
 #endif /* CONFIG_STACK_TRACER */
+       "  events/\t\t- Directory containing all trace event subsystems:\n"
+       "      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
+       "  events/<system>/\t- Directory containing all trace events for 
<system>:\n"
+       "      enable\t\t- Write 0/1 to enable/disable tracing of all <system> 
events\n"
+       "      filter\t\t- If set, only events passing filter are traced\n"
+       "  events/<system>/<event>/\t- Directory containing control files for 
<event>:\n"
+       "      enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
+       "      filter\t\t- If set, only events passing filter are traced\n"
+       "      trigger\t\t- If set, a command to perform when event is hit\n"
+       "            Format: <trigger>[:count][if <filter>]\n"
+       "           trigger: traceon, traceoff\n"
+       "                    enable_event:<system>:<event>\n"
+       "                    disable_event:<system>:<event>\n"
+#ifdef CONFIG_STACKTRACE
+       "                    stacktrace\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+       "                    snapshot\n"
+#endif
+       "           example: echo traceoff > 
events/block/block_unplug/trigger\n"
+       "                    echo traceoff:3 > 
events/block/block_unplug/trigger\n"
+       "                    echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > 
events/block/block_unplug/trigger\n"
+       "           The first disables tracing every time block_unplug is 
hit.\n"
+       "           The second disables tracing the first 3 times block_unplug 
is hit.\n"
+       "           The third enables the kmalloc event the first 3 times 
block_unplug\n"
+       "             is hit and has value of greater than 1 for the 'nr_rq' 
event field.\n"
+       "           To remove a trigger without a count:\n"
+       "             echo '!<trigger> > <system>/<event>/trigger\n"
+       "           To remove a trigger with a count:\n"
+       "             echo '!<trigger>:0 > <system>/<event>/trigger\n"
+       "           Filters can be ignored when removing a trigger.\n"
 ;
 
 static ssize_t
-- 
1.8.4.3


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