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tracing: Add enabling of events to boot instances

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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.

Link: https://lkml.kernel.org/r/20230207173026.386114535@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2023-02-07 12:28:51 -05:00
parent cb1f98c5e5
commit c484648083
4 changed files with 24 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
Documentation/admin-guide/kernel-parameters.txt
View File

@ -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

4
kernel/trace/trace.c
View File

@ -10188,6 +10188,10 @@ __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);
}
}
}

2
kernel/trace/trace.h
View File

@ -1334,6 +1334,8 @@ 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)

9
kernel/trace/trace_events.c
View File

@ -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;
}