From 4114fbfd02f12d7a58cc4bd6fc36e0925266f9f7 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 10 Sep 2020 21:39:07 +0900 Subject: [PATCH] tracing: Enable creating new instance early boot 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 Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 53 +++++++++++++++++++++++++++------- kernel/trace/trace.h | 7 +++++ kernel/trace/trace_functions.c | 22 +++++++++----- 3 files changed, 63 insertions(+), 19 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c35fcd2f2529..6211a13b3327 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -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 diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 0d3a405fe446..525434145eea 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1125,6 +1125,8 @@ extern int ftrace_is_dead(void); int ftrace_create_function_files(struct trace_array *tr, struct dentry *parent); void ftrace_destroy_function_files(struct trace_array *tr); +int ftrace_allocate_ftrace_ops(struct trace_array *tr); +void ftrace_free_ftrace_ops(struct trace_array *tr); void ftrace_init_global_array_ops(struct trace_array *tr); void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func); void ftrace_reset_array_ops(struct trace_array *tr); @@ -1146,6 +1148,11 @@ ftrace_create_function_files(struct trace_array *tr, { return 0; } +static inline int ftrace_allocate_ftrace_ops(struct trace_array *tr) +{ + return 0; +} +static inline void ftrace_free_ftrace_ops(struct trace_array *tr) { } static inline void ftrace_destroy_function_files(struct trace_array *tr) { } static inline __init void ftrace_init_global_array_ops(struct trace_array *tr) { } diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index dd4dff71d89a..2c2126e1871d 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -34,10 +34,14 @@ enum { TRACE_FUNC_OPT_STACK = 0x1, }; -static int allocate_ftrace_ops(struct trace_array *tr) +int ftrace_allocate_ftrace_ops(struct trace_array *tr) { struct ftrace_ops *ops; + /* The top level array uses the "global_ops" */ + if (tr->flags & TRACE_ARRAY_FL_GLOBAL) + return 0; + ops = kzalloc(sizeof(*ops), GFP_KERNEL); if (!ops) return -ENOMEM; @@ -48,15 +52,19 @@ static int allocate_ftrace_ops(struct trace_array *tr) tr->ops = ops; ops->private = tr; + return 0; } +void ftrace_free_ftrace_ops(struct trace_array *tr) +{ + kfree(tr->ops); + tr->ops = NULL; +} int ftrace_create_function_files(struct trace_array *tr, struct dentry *parent) { - int ret; - /* * The top level array uses the "global_ops", and the files are * created on boot up. @@ -64,9 +72,8 @@ int ftrace_create_function_files(struct trace_array *tr, if (tr->flags & TRACE_ARRAY_FL_GLOBAL) return 0; - ret = allocate_ftrace_ops(tr); - if (ret) - return ret; + if (!tr->ops) + return -EINVAL; ftrace_create_filter_files(tr->ops, parent); @@ -76,8 +83,7 @@ int ftrace_create_function_files(struct trace_array *tr, void ftrace_destroy_function_files(struct trace_array *tr) { ftrace_destroy_filter_files(tr->ops); - kfree(tr->ops); - tr->ops = NULL; + ftrace_free_ftrace_ops(tr); } static int function_trace_init(struct trace_array *tr)