Re: [PATCH tip 1/1] tracing: handle unregistering the currenttracer

From: Arnaldo Carvalho de Melo
Date: Mon Feb 09 2009 - 06:52:24 EST


Em Mon, Feb 09, 2009 at 10:58:16AM +0100, Ingo Molnar escreveu:
>
> * Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
>
> > Impact: simplification
> >
> > Instead of requiring that plugins have the sequence:
> >
> > my_tracer_stop(my_trace_array);
> > unregister_tracer(my_tracer);
> >
> > it should be possible just do a:
> >
> > unregister_tracer(my_tracer);
> >
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > ---
> > kernel/trace/trace.c | 9 +++++++++
> > 1 files changed, 9 insertions(+), 0 deletions(-)
>
> Applied to tip/tracing/ftrace, thanks Arnaldo!
>
> Nice one - we should try to shoot for the smallest physically
> possible linecount for any new (possibly trivial) tracer plugin.

That and also for as few as possible EXPORT_SYMBOL_GPL entries, now, for
converting net/ipv4/tcp_probe.c to an ftrace plugin + one tracepoint at
tcp_rcv_established we need:

doppio linux-2.6-tip]$ grep ^+EXPORT_SYMBOL ~/tcp_cwnd_tracer.patch
+EXPORT_SYMBOL_GPL(register_tracer);
+EXPORT_SYMBOL_GPL(unregister_tracer);
+EXPORT_SYMBOL_GPL(tracing_record_cmdline);
+EXPORT_SYMBOL_GPL(trace_buffer_lock_reserve);
+EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
+EXPORT_SYMBOL_GPL(trace_seq_printf);
+EXPORT_SYMBOL_GPL(register_ftrace_event);
+EXPORT_SYMBOL_GPL(unregister_ftrace_event);
[acme@doppio linux-2.6-tip]$

- Arnaldo
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