Re: [PATCH] tracing: add trace console

Johannes Berg
2011-11-16T14:30:52Z

On Wed, 2011-11-16 at 15:25 +0100, Peter Zijlstra wrote:

> > > kernel/trace/Kconfig | 13 ++++++++++
> > > kernel/trace/Makefile | 2 +
> > > kernel/trace/trace-console.c | 55 +++++++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 70 insertions(+)
> > >
> > > --- a/kernel/trace/Kconfig 2011-11-16 11:11:27.000000000 +0100
> > > +++ b/kernel/trace/Kconfig 2011-11-16 11:11:35.000000000 +0100
> > > @@ -368,6 +368,19 @@ config BLK_DEV_IO_TRACE
> > >
> > > If unsure, say N.
> > >
> > > +config TRACE_CONSOLE
> > > + tristate "Support for a tracing console"
> > > + help
> > > + Say M (or Y if you must, but this is not recommended)
>
> Why not?

It'll always be registered and you have no way to turn it off then, so
you can't trace without getting every printk. I didn't want to add extra
API to toggle it, but building it in might be a bit odd that way.

johannes