Re: [PATCH] rcu: convert rcupreempt trace to seq file

Ingo Molnar
2009-01-11T01:40:08Z

* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> On Sat, Jan 10, 2009 at 03:48:46PM +0800, Li Zefan wrote:
> > Impact: also fix a bug in show_rcustats()
> >
> > Use seq file for simplification, and the global buffer and mutex can be
> > removed.
>
> Looks very good, and passes my tests.
>
> > While doing this, I found rcustats will never show 'ggp' and 'rcc' fields
> > due to a bug in show_rcustats().
>
> Good eyes!
>
> The only change I ask is that you pull the contents of
> rcupreempt_debugfs_init() into the now-one-line rcupreempt_trace_init().
>
> With that change:
>
> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>
> > ---
> > kernel/rcupreempt_trace.c | 155 ++++++++++++++++++++-------------------------

i think the whole kernel/rcupreempt_trace.c file might be a good candidate
for the 'statistical tracing' extensions to ftrace that Frederice is
working on.

That way there would just be a few tracepoints, and the rest would be done
in kernel/tracing/trace_rcupreempt.c, or so.
Ingo