tracing: Add 'enable_event' and 'disable_event' event trigger commands
authorTom Zanussi <tom.zanussi@linux.intel.com>
Thu, 24 Oct 2013 13:59:28 +0000 (08:59 -0500)
committerSteven Rostedt <rostedt@goodmis.org>
Sun, 22 Dec 2013 03:02:16 +0000 (22:02 -0500)
commit7862ad1846e994574cb47dc503cc2b1646ea6593
treecec348fd60d6f85d1ae772996d0b8241a31d5b35
parentf21ecbb35f865a508073c0e73854da469a07f278
tracing: Add 'enable_event' and 'disable_event' event trigger commands

Add 'enable_event' and 'disable_event' event_command commands.

enable_event and disable_event event triggers are added by the user
via these commands in a similar way and using practically the same
syntax as the analagous 'enable_event' and 'disable_event' ftrace
function commands, but instead of writing to the set_ftrace_filter
file, the enable_event and disable_event triggers are written to the
per-event 'trigger' files:

    echo 'enable_event:system:event' > .../othersys/otherevent/trigger
    echo 'disable_event:system:event' > .../othersys/otherevent/trigger

The above commands will enable or disable the 'system:event' trace
events whenever the othersys:otherevent events are hit.

This also adds a 'count' version that limits the number of times the
command will be invoked:

    echo 'enable_event:system:event:N' > .../othersys/otherevent/trigger
    echo 'disable_event:system:event:N' > .../othersys/otherevent/trigger

Where N is the number of times the command will be invoked.

The above commands will will enable or disable the 'system:event'
trace events whenever the othersys:otherevent events are hit, but only
N times.

This also makes the find_event_file() helper function extern, since
it's useful to use from other places, such as the event triggers code,
so make it accessible.

Link: http://lkml.kernel.org/r/f825f3048c3f6b026ee37ae5825f9fc373451828.1382622043.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
include/linux/ftrace_event.h
kernel/trace/trace.h
kernel/trace/trace_events.c
kernel/trace/trace_events_trigger.c