From: "Steven Rostedt (Google)" <[email protected]>
Add the format of:
trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
That will create the "foo" instance and enable the sched_switch event
(here were the "sched" system is explicitly specified), the
irq_handler_entry event, and all events under the system initcall.
Signed-off-by: Steven Rostedt (Google) <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 14 ++++++++++++++
kernel/trace/trace.c | 4 ++++
kernel/trace/trace.h | 2 ++
kernel/trace/trace_events.c | 9 ++++-----
4 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cec486217ccc..7a7f41652719 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6278,6 +6278,20 @@
/sys/kernel/tracing/instances
+ Events can be enabled at the time the instance is created
+ via:
+
+ trace_instance=<name>,<system1>:<event1>,<system2>:<event2>
+
+ Note, the "<system*>:" portion is optional if the event is
+ unique.
+
+ trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
+
+ will enable the "sched_switch" event (note, the "sched:" is optional, and
+ the same thing would happen if it was left off). The irq_handler_entry
+ event, and all events under the "initcall" system.
+
trace_options=[option-list]
[FTRACE] Enable or disable tracer options at boot.
The option-list is a comma delimited list of options
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 34ed504ffca9..e8c52a8d712e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -10189,6 +10189,10 @@ __init static void enable_instances(void)
}
/* Allow user space to delete it */
trace_array_put(tr);
+
+ while ((tok = strsep(&curr_str, ","))) {
+ early_enable_events(tr, tok, true);
+ }
}
}
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e46a49269be2..a56b0b7d23ef 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1330,6 +1330,8 @@ DECLARE_PER_CPU(int, trace_buffered_event_cnt);
void trace_buffered_event_disable(void);
void trace_buffered_event_enable(void);
+void early_enable_events(struct trace_array *tr, char *buf, bool disable_first);
+
static inline void
__trace_event_discard_commit(struct trace_buffer *buffer,
struct ring_buffer_event *event)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b07931ad97de..cf3fd74fa675 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3750,10 +3750,9 @@ static __init int event_trace_memsetup(void)
return 0;
}
-static __init void
-early_enable_events(struct trace_array *tr, bool disable_first)
+__init void
+early_enable_events(struct trace_array *tr, char *buf, bool disable_first)
{
- char *buf = bootup_event_buf;
char *token;
int ret;
@@ -3806,7 +3805,7 @@ static __init int event_trace_enable(void)
*/
__trace_early_add_events(tr);
- early_enable_events(tr, false);
+ early_enable_events(tr, bootup_event_buf, false);
trace_printk_start_comm();
@@ -3834,7 +3833,7 @@ static __init int event_trace_enable_again(void)
if (!tr)
return -ENODEV;
- early_enable_events(tr, true);
+ early_enable_events(tr, bootup_event_buf, true);
return 0;
}
--
2.39.0
On Wed, Jan 11, 2023 at 09:56:38AM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <[email protected]>
>
> Add the format of:
>
> trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
>
> That will create the "foo" instance and enable the sched_switch event
> (here were the "sched" system is explicitly specified), the
> irq_handler_entry event, and all events under the system initcall.
>
> Signed-off-by: Steven Rostedt (Google) <[email protected]>
You can add:
Reviewed-by: Ross Zwisler <[email protected]>