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Date: Fri, 16 Apr 2010 10:14:40 -0700
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Subject: Re: [PATCH 3/3] Stop tracing on a schedule bug
From: Chase Douglas <chase.douglas@canonical.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
       Frederic Weisbecker <fweisbec@gmail.com>, linux-kernel@vger.kernel.org,
       Ingo Molnar <mingo@elte.hu>, Randy Dunlap <randy.dunlap@oracle.com>
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On Fri, Apr 16, 2010 at 9:46 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 2010-04-15 at 21:01 -0700, Chase Douglas wrote:
>> > 2) tracing off can be done via filters on functions and/or events
>> >   already - so I doubt that the tracing_off_event(level) is necessary
>> >   at all.
>> >
>> >   schedule_bug() definitely deserves a separate trace_schedule_bug()
>> >   event which can be used to stop the tracer by already existing
>> >   functionality.
>>
>> Steven said he would be fine with a separate TRACE_EVENT_<blah> macro
>> for the schedule bug if needed, but I'm not sure we need to go that
>> far. If it's configurable through debugfs at run time then it serves
>> my purpose. Unless you feel we should have finer grained control
>> specifically for scheduling while atomic bugs, I'll just leave it as
>> TRACE_EVENT_WARN.
>
> I actually like Thomas's idea better. I need to add the "stop trace on
> event" functionality, and we can insert trace events for bugs, and not
> have this whole "stop tracing here" functions. Instead we could just add
> tracepoints and have a way to pick and choose where to stop tracing.
>
> add a:
>
> include/trace/events/errors.h
>
> #define TRACE_SYSTEM errors
>
> TRACE_EVENT(sched_bug, ....)
>
> etc,
>
>
> When I get back home, I'll add this functionality to stop tracing on
> events. Perhaps I'll even add "TRACE_SUB_SYSTEM" so in the events
> directory, we can have sub layers:
>
> events/errors/BUG/...
> events/errors/WARNING/...
>
> etc

Ok, I see where this is going now. I agree this sounds like a much
better approach. I'll wait for the implementation of the stop tracing
on event functionality so I know how it will work, and then I can
submit patches for the BUG, WARN, panic, and schedule_bug paths.

-- Chase