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tracing: Add needs_rec flag to event triggers 

Add a new needs_rec flag for triggers that require unconditional
access to trace records in order to function.

Normally a trigger requires access to the contents of a trace record
only if it has a filter associated with it (since filters need the
contents of a record in order to make a filtering decision).  Some
types of triggers, such as 'hist' triggers, require access to trace
record contents independent of the presence of filters, so add a new
flag for those triggers.

Link: http://lkml.kernel.org/r/7be8fa38f9b90fdb6c47ca0f98d20a07b9fd512b.1449767187.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Tom Zanussi 2015-12-10 12:50:48 -06:00 committed by Steven Rostedt
parent 104f281044
commit a5863dae84
2 changed files with 9 additions and 1 deletions
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7
kernel/trace/trace.h
View File

@ -1292,6 +1292,12 @@ struct event_trigger_ops {
* itself logs to the trace buffer, this flag should be set,
* otherwise it can be left unspecified.
*
* @needs_rec: A flag that says whether or not this command needs
* access to the trace record in order to perform its function,
* regardless of whether or not it has a filter associated with
* it (filters make a trigger require access to the trace record
* but are not always present).
*
* All the methods below, except for @set_filter(), must be
* implemented.
*
@ -1332,6 +1338,7 @@ struct event_command {
char *name;
enum event_trigger_type trigger_type;
bool post_trigger;
bool needs_rec;
int (*func)(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *params);

3
kernel/trace/trace_events_trigger.c
View File

@ -493,7 +493,8 @@ void update_cond_flag(struct trace_event_file *file)
bool set_cond = false;
list_for_each_entry_rcu(data, &file->triggers, list) {
if (data->filter || data->cmd_ops->post_trigger) {
if (data->filter || data->cmd_ops->post_trigger ||
data->cmd_ops->needs_rec) {
set_cond = true;
break;
}