This patch splits trace event initialization in two stages:
* ftrace enable
* sysfs event entry creation
This allows to capture trace events from an earlier point
by using 'trace_event' kernel parameter and is important
to trace boot-up allocations.
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Ingo Molnar <mi...@redhat.com>
Signed-off-by: Ezequiel Garcia <elezegar...@gmail.com>
---
kernel/trace/trace_events.c | 71 ++++++++++++++++++++++++++++++++-----------
1 files changed, 53 insertions(+), 18 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 29111da..3055bc9 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1450,6 +1450,49 @@ static __init int setup_trace_event(char *str)
}
__setup("trace_event=", setup_trace_event);
+static __init int event_trace_enable(void)
+{
+ struct ftrace_event_call **iter, *call;
+ char *buf = bootup_event_buf;
+ char *token;
+ int ret;
+
+ for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
+
+ call = *iter;
+
+ /* The linker may leave blanks */
+ if (!call->name)
+ continue;
+
+ if (!call->class->raw_init)
+ continue;
+
+ ret = call->class->raw_init(call);
+ if (ret < 0) {
+ if (ret != -ENOSYS)
+ pr_warning("Could not initialize trace
events/%s\n",
+ call->name);
+ continue;
+ }
+ list_add(&call->list, &ftrace_events);
+ }
+
+ while (true) {
+ token = strsep(&buf, ",");
+
+ if (!token)
+ break;
+ if (!*token)
+ continue;
+
+ ret = ftrace_set_clr_event(token, 1);
+ if (ret)
+ pr_warning("Failed to enable trace event: %s\n", token);
+ }
+ return 0;
+}
+
static __init int event_trace_init(void)
{
struct ftrace_event_call **call;
@@ -1457,8 +1500,6 @@ static __init int event_trace_init(void)
struct dentry *entry;
struct dentry *d_events;
int ret;
- char *buf = bootup_event_buf;
- char *token;
d_tracer = tracing_init_dentry();
if (!d_tracer)
@@ -1497,24 +1538,17 @@ static __init int event_trace_init(void)
if (trace_define_common_fields())
pr_warning("tracing: Failed to allocate common fields");
+ /*
+ * Early initialization already enabled ftrace event.
+ * Now it's only necessary to create the event directory.
+ */
for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
- __trace_add_event_call(*call, NULL, &ftrace_event_id_fops,
- &ftrace_enable_fops,
- &ftrace_event_filter_fops,
- &ftrace_event_format_fops);
- }
-
- while (true) {
- token = strsep(&buf, ",");
-
- if (!token)
- break;
- if (!*token)
- continue;
- ret = ftrace_set_clr_event(token, 1);
- if (ret)
- pr_warning("Failed to enable trace event: %s\n", token);
+ event_create_dir(*call, d_events,
+ &ftrace_event_id_fops,
+ &ftrace_enable_fops,
+ &ftrace_event_filter_fops,
+ &ftrace_event_format_fops);
}
ret = register_module_notifier(&trace_module_nb);
@@ -1523,6 +1557,7 @@ static __init int event_trace_init(void)
return 0;
}
+early_initcall(event_trace_enable);
fs_initcall(event_trace_init);
#ifdef CONFIG_FTRACE_STARTUP_TEST
--
1.7.8.6
--
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