| Message ID | 20220323152257.7871-3-mark-pk.tsai@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | tracing: make tracer_init_tracefs initcall asynchronous | expand |
On Wed, 23 Mar 2022 23:22:57 +0800 Mark-PK Tsai <mark-pk.tsai@mediatek.com> wrote: > +static __init int tracer_init_tracefs(void) > +{ > + int ret; > + > + trace_access_lock_init(); > + > + ret = tracing_init_dentry(); > + if (ret) > + return 0; > + > + INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); > + if (!eval_map_wq) > + tracer_init_tracefs_work_func(&tracerfs_init_work); Why go through the bother of doing the INIT_WORK if eval_map_wq is not created? Just do: if (eval_map_wq) { INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); queue_work(eval_map_wq, &tracerfs_init_work); } else { tracer_init_tracefs_work_func(NULL); } But that's just a nit anyway. -- Steve > + else > + queue_work(eval_map_wq, &tracerfs_init_work); > > return 0; > }
> > +static __init int tracer_init_tracefs(void) > > +{ > > + int ret; > > + > > + trace_access_lock_init(); > > + > > + ret = tracing_init_dentry(); > > + if (ret) > > + return 0; > > + > > + INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); > > + if (!eval_map_wq) > > + tracer_init_tracefs_work_func(&tracerfs_init_work); > > Why go through the bother of doing the INIT_WORK if eval_map_wq is not > created? Just do: > > if (eval_map_wq) { > INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); > queue_work(eval_map_wq, &tracerfs_init_work); > } else { > tracer_init_tracefs_work_func(NULL); > } Got it, I will update it in v4. Thanks! > > But that's just a nit anyway. > > -- Steve > > > > > + else > > + queue_work(eval_map_wq, &tracerfs_init_work); > > > > return 0; > > }
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 85ec758c4455..2974ae056068 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9571,6 +9571,7 @@ extern struct trace_eval_map *__stop_ftrace_eval_maps[]; static struct workqueue_struct *eval_map_wq __initdata; static struct work_struct eval_map_work __initdata; +static struct work_struct tracerfs_init_work __initdata; static void __init eval_map_work_func(struct work_struct *work) { @@ -9596,6 +9597,8 @@ static int __init trace_eval_init(void) return 0; } +subsys_initcall(trace_eval_init); + static int __init trace_eval_sync(void) { /* Make sure the eval map updates are finished */ @@ -9678,15 +9681,8 @@ static struct notifier_block trace_module_nb = { }; #endif /* CONFIG_MODULES */ -static __init int tracer_init_tracefs(void) +static __init void tracer_init_tracefs_work_func(struct work_struct *work) { - int ret; - - trace_access_lock_init(); - - ret = tracing_init_dentry(); - if (ret) - return 0; event_trace_init(); @@ -9708,8 +9704,6 @@ static __init int tracer_init_tracefs(void) trace_create_file("saved_tgids", TRACE_MODE_READ, NULL, NULL, &tracing_saved_tgids_fops); - trace_eval_init(); - trace_create_eval_file(NULL); #ifdef CONFIG_MODULES @@ -9724,6 +9718,23 @@ static __init int tracer_init_tracefs(void) create_trace_instances(NULL); update_tracer_options(&global_trace); +} + +static __init int tracer_init_tracefs(void) +{ + int ret; + + trace_access_lock_init(); + + ret = tracing_init_dentry(); + if (ret) + return 0; + + INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func); + if (!eval_map_wq) + tracer_init_tracefs_work_func(&tracerfs_init_work); + else + queue_work(eval_map_wq, &tracerfs_init_work); return 0; }
Move trace_eval_init() to subsys_initcall to make it start earlier. And to avoid tracer_init_tracefs being blocked by trace_event_sem which trace_eval_init() hold [1], queue tracer_init_tracefs() to eval_map_wq to let the two works being executed sequentially. It can speed up the initialization of kernel as result of making tracer_init_tracefs asynchronous. On my arm64 platform, it reduce ~20ms of 125ms which total time do_initcalls spend. [1]: https://lore.kernel.org/r/68d7b3327052757d0cd6359a6c9015a85b437232.camel@pengutronix.de Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> --- kernel/trace/trace.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-)