Re: [PATCH 1/2] kernel/trace: call helper function to check global_trace

From: Yaowei Bai
Date: Wed Sep 23 2015 - 09:50:32 EST


On Tue, Sep 22, 2015 at 09:58:47AM -0400, Steven Rostedt wrote:
> On Tue, 22 Sep 2015 21:43:12 +0800
> Yaowei Bai <bywxiaobai@xxxxxxx> wrote:
>
> > Use helper function tracing_is_enabled() to check if global_trace
> > has been disabled.
>
> Actually, I prefer not to.
>
> >
> > No functional change.
> >
> > Signed-off-by: Yaowei Bai <bywxiaobai@xxxxxxx>
> > ---
> > kernel/trace/trace.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> > index 6e79408..b0bd322a 100644
> > --- a/kernel/trace/trace.c
> > +++ b/kernel/trace/trace.c
> > @@ -7111,7 +7111,7 @@ __init static int tracer_alloc_buffers(void)
> > goto out_free_savedcmd;
> > }
> >
> > - if (global_trace.buffer_disabled)
> > + if (!tracing_is_enabled())
>
> Yes, the above is functionally equivalent. But tracing_is_enabled() is
> not a "helper function" but actually an external interface for other
> parts of the tracing system.

Got it.

>
> The above code is the actual setup of the tracing infrastructure, that
> is used to allocate the tracing buffers. They may now use the same
> logic, but there's no guarantee that it will in the future.

Appreciate you wonderful explanation.

>
> -- Steve
>
>
> > tracing_off();
> >
> > if (trace_boot_clock) {

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