Re: [PATCH 0/4] [GIT PULL] for tip/tracing/filters

[Tom Zanussi <tzanussi@gmail.com>]

On Sat, 2009-04-04 at 11:42 -0400, Steven Rostedt wrote:
> On Sat, 4 Apr 2009, Tom Zanussi wrote:
> > On Fri, 2009-04-03 at 10:36 -0400, Steven Rostedt wrote:
> > 
> > I'm guessing the problem is that CONFIG_EVENT_TRACER wasn't selected but
> > should have been, because those tracers all now export events
> > (trace_event_types.h, included by trace_export.c).  I'm not sure this is
> > the right way to do it, but the patch below selects EVENT_TRACER if
> > TRACING is selected (a couple of the exported events belong to bprint
> > and print, which don't have a config option other than TRACING, so it
> > seems to belong there).
> > 
> > Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
> > 
> > ---
> >  kernel/trace/Kconfig |    3 ++-
> >  1 files changed, 2 insertions(+), 1 deletions(-)
> > 
> > diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> > index 8a41360..a061746 100644
> > --- a/kernel/trace/Kconfig
> > +++ b/kernel/trace/Kconfig
> > @@ -56,6 +56,7 @@ config TRACING
> >  	select TRACEPOINTS
> >  	select NOP_TRACER
> >  	select BINARY_PRINTF
> > +	select EVENT_TRACER
> 
> Yeah, we can do this.
> 
> >  
> >  #
> >  # Minimum requirements an architecture has to meet for us to
> > @@ -177,7 +178,7 @@ config CONTEXT_SWITCH_TRACER
> >  
> >  config EVENT_TRACER
> >  	bool "Trace various events in the kernel"
> > -	select TRACING
> > +	depends on TRACING
> 
> This means we can only select EVENT_TRACER if something else has been 
> selected. Can't we keep the "select TRACING" here.
> 

Keeping 'select TRACING' here gives this error:

kernel/trace/Kconfig:53:error: found recursive dependency: TRACING ->
EVENT_TRACER -> TRACING

I'll have to play around with it some more...

Tom

> That way, we could just select EVENT_TRACER, but if anything other 
> tracer is selected, we automatically get EVENT_TRACER.
> 
> The logic would be, if you pick any tracer you get the EVENT_TRACER.
> But you can still just ask for the EVENT_TRACER with no other tracer.

> -- Steve
> 
> 
> 
> >  	help
> >  	  This tracer hooks to various trace points in the kernel
> >  	  allowing the user to pick and choose which trace point they
> > -- 
> > 1.5.6.3
> > 
> > 
> > 
> >