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

[Ingo Molnar <mingo@elte.hu>]

* 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