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tracing: Enable creating new instance early boot

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Enable creating new trace_array instance in early boot stage.
If the instances directory is not created, postpone it until
the tracefs is initialized.

Link: https://lkml.kernel.org/r/159974154763.478751.6289753509587233103.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2020-09-10 21:39:07 +09:00 • committed by Steven Rostedt (VMware)
parent a838deab4e
commit 4114fbfd02
3 changed files with 63 additions and 19 deletions
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53
kernel/trace/trace.c
View file

@ -8636,6 +8636,24 @@ struct trace_array *trace_array_find_get(const char *instance)
return tr;
}
static int trace_array_create_dir(struct trace_array *tr)
{
int ret;
tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
if (!tr->dir)
return -EINVAL;
ret = event_trace_add_tracer(tr->dir, tr);
if (ret)
tracefs_remove(tr->dir);
init_tracer_tracefs(tr, tr->dir);
__update_tracer_options(tr);
return ret;
}
static struct trace_array *trace_array_create(const char *name)
{
struct trace_array *tr;
@ -8671,30 +8689,27 @@ static struct trace_array *trace_array_create(const char *name)
if (allocate_trace_buffers(tr, trace_buf_size) < 0)
goto out_free_tr;
tr->dir = tracefs_create_dir(name, trace_instance_dir);
if (!tr->dir)
if (ftrace_allocate_ftrace_ops(tr) < 0)
goto out_free_tr;
ret = event_trace_add_tracer(tr->dir, tr);
if (ret) {
tracefs_remove(tr->dir);
goto out_free_tr;
}
ftrace_init_trace_array(tr);
init_tracer_tracefs(tr, tr->dir);
init_trace_flags_index(tr);
__update_tracer_options(tr);
if (trace_instance_dir) {
ret = trace_array_create_dir(tr);
if (ret)
goto out_free_tr;
}
list_add(&tr->list, &ftrace_trace_arrays);
tr->ref++;
return tr;
out_free_tr:
ftrace_free_ftrace_ops(tr);
free_trace_buffers(tr);
free_cpumask_var(tr->tracing_cpumask);
kfree(tr->name);
@ -8852,11 +8867,27 @@ static int instance_rmdir(const char *name)
static __init void create_trace_instances(struct dentry *d_tracer)
{
struct trace_array *tr;
trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
instance_mkdir,
instance_rmdir);
if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
return;
mutex_lock(&event_mutex);
mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (!tr->name)
continue;
if (MEM_FAIL(trace_array_create_dir(tr) < 0,
"Failed to create instance directory\n"))
break;
}
mutex_unlock(&trace_types_lock);
mutex_unlock(&event_mutex);
}
static void