Re: [PATCH 2/3] ftrace: Add debug_print trace to print data from kernel to userspace

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On Fri, Nov 14, 2008 at 03:39:29PM +0100, Frédéric Weisbecker wrote:
> 2008/11/14 Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>:
> > We also want to make sure dp_printk doesn't do anything when tracer
> > is disabled. We do
> >
> > int do_dp_printk(const char *fmt, ...)
> > {
> >        int ret;
> >        va_list args;
> >
> >        if (!tracer_enabled)
> >                return 0;
> 
> 
> In this case you just have to do
> echo 0 > /debug/tracing/tracing_enabled
> And the entries will not be printed anymore....

That would prevent us to have both dp_printk and debug_dump
used at the same time. Both will them depend on the tracer_enabled
flag. That means the output of these call will also interact with
rest of the tracer output.

-aneesh