[PATCH 3/6] tracing: Enable adding dynamic events early stage
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: 2020-09-10 12:46:07
Also in:
lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
Split the event fields initialization from creating new event directory. This allows the boot-time tracing to define dynamic events before initializing events directory on tracefs. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- kernel/trace/trace_events.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a2531301b44f..720b0d72ea52 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c@@ -38,6 +38,7 @@ DEFINE_MUTEX(event_mutex); LIST_HEAD(ftrace_events); static LIST_HEAD(ftrace_generic_fields); static LIST_HEAD(ftrace_common_fields); +static bool eventdir_initialized; #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
@@ -2486,7 +2487,10 @@ __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr) if (!file) return -ENOMEM; - return event_create_dir(tr->event_dir, file); + if (eventdir_initialized) + return event_create_dir(tr->event_dir, file); + else + return event_define_fields(call); } /*
@@ -3483,6 +3487,9 @@ __init int event_trace_init(void) if (ret) pr_warn("Failed to register trace events module notifier\n"); #endif + + eventdir_initialized = true; + return 0; }