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author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-05-09 14:17:48 -0400 |
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committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-05-29 08:28:53 -0400 |
commit | 3dd8095368475a9538895ce757b63dd311e58fe8 (patch) | |
tree | 33d00f2039b91119b01fe7f46b403bf5360580df /kernel/trace/trace_export.c | |
parent | 5d948c86bb332cd143f4b2dc21d949baf38e29aa (diff) | |
download | linux-stable-3dd8095368475a9538895ce757b63dd311e58fe8.tar.gz linux-stable-3dd8095368475a9538895ce757b63dd311e58fe8.tar.bz2 linux-stable-3dd8095368475a9538895ce757b63dd311e58fe8.zip |
tracing: Add trigger file for trace_markers tracefs/ftrace/print
Allow writing to the trace_markers file initiate triggers defined in
tracefs/ftrace/print/trigger file. This will allow of user space to trigger
the same type of triggers (including histograms) that the trace events use.
Had to create a ftrace_event_register() function that will become the
trace_marker print event's reg() function. This is required because of how
triggers are enabled:
event_trigger_write() {
event_trigger_regex_write() {
trigger_process_regex() {
for p in trigger_commands {
p->func(); /* trigger_snapshot_cmd->func */
event_trigger_callback() {
cmd_ops->reg() /* register_trigger() */ {
trace_event_trigger_enable_disable() {
trace_event_enable_disable() {
call->class->reg();
Without the reg() function, the trigger code will call a NULL pointer and
crash the system.
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Karim Yaghmour <karim.yaghmour@opersys.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Suggested-by: Joel Fernandes <joelaf@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_export.c')
-rw-r--r-- | kernel/trace/trace_export.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index d842f1eadfe5..45630a76ed3a 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -14,6 +14,13 @@ #include "trace_output.h" +/* Stub function for events with triggers */ +static int ftrace_event_register(struct trace_event_call *call, + enum trace_reg type, void *data) +{ + return 0; +} + #undef TRACE_SYSTEM #define TRACE_SYSTEM ftrace |