Messages in this thread | | | Date | Wed, 14 Jan 2015 10:09:05 +0900 | From | Namhyung Kim <> | Subject | Re: [PATCH 1/2] tracing: Move enabling tracepoints to just after rcu_init() |
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On Wed, Jan 14, 2015 at 08:12:40AM +0800, Wang Nan wrote: > Ping... > > On 2015/1/9 12:06, Wang Nan wrote: > > Hi Steven Rostedt, > > > > During studying your code we find a problem, please see below. > > > >> > >> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> > >> > >> Enabling tracepoints at boot up can be very useful. The tracepoint > >> can be initialized right after RCU has been. There's no need to > >> wait for the early_initcall() to be called. That's too late for some > >> things that can use tracepoints for debugging. Move the logic to > >> enable tracepoints out of the initcalls and into init/main.c to > >> right after rcu_init(). > >> > >> This also allows trace_printk() to be used early too. > >> > >> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1412121539300.16494@nanos > >> Link: http://lkml.kernel.org/r/20141214164104.307127356@goodmis.org > >> > >> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > >> Suggested-by: Thomas Gleixner <tglx@linutronix.de> > >> Tested-by: Thomas Gleixner <tglx@linutronix.de> > >> Acked-by: Thomas Gleixner <tglx@linutronix.de> > >> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> > > > > [...] > > > >> +void __init trace_init(void) > >> +{ > >> + tracer_alloc_buffers(); > >> + init_ftrace_syscalls(); > >> + trace_event_init(); > >> +} > >> + > > > > [...] > > > >> + > >> +void __init trace_event_init(void) > >> +{ > >> + event_trace_memsetup(); > >> + init_ftrace_syscalls(); > >> + event_trace_enable(); > >> +} > >> + > > > > init_ftrace_syscalls() get called twice by trace_init() and trace_event_init(), some resources are wasted. > > At lease one of them can be removed.
I think it's more natural to keep it in the trace_event_init().
Thanks, Namhyung
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