Re: [PATCH] ftrace: add ftrace_graph_max_depth kernel parameter

[Steven Rostedt]

On Thu, 2 Mar 2017 19:38:27 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Thu,  2 Mar 2017 16:12:15 -0800
> Todd Brandt <todd.e.brandt@xxxxxxxxxxxxxxx> wrote:
> 
> > Early trace callgraphs can be extremely large on systems with
> > several seconds of boot time. The max_depth parameter limits how
> > deep the graph trace goes and reduces the output size. This
> > parameter is the same as the max_graph_depth file in debugfs.  
> 
> I'll take this with one modification I'll make. s/debugfs/tracefs/
> because it's really the tracefs file system now. It just happens to be
> automatically mounted in the debugfs file system. But can be by itself
> in /sys/kernel/tracing/
> 
> -- Steve
> 
> > 
> > Signed-off-by: Todd Brandt <todd.e.brandt@xxxxxxxxxxxxxxx>
> > ---
> >  Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
> >  kernel/trace/ftrace.c                           | 9 +++++++++
> >  2 files changed, 15 insertions(+)
> > 
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 986e443..1a8575f 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -1183,6 +1183,12 @@
> >  			functions that can be changed at run time by the
> >  			set_graph_notrace file in the debugfs tracing directory.

I need to make a patch to update the old documentation to reflect this
as well. But I'll do that another time.

-- Steve