Re: [PATCH tip/core/rcu 20/45] torture: Include "Stopping" string to torture_kthread_stopping()

[Josh Triplett]

On Fri, May 09, 2014 at 05:42:59PM -0700, Paul E. McKenney wrote:
> On Fri, May 09, 2014 at 05:16:57PM -0700, Josh Triplett wrote:
> > On Fri, May 09, 2014 at 05:13:46PM -0700, Paul E. McKenney wrote:
> > > On Wed, May 07, 2014 at 02:37:36PM -0700, josh@xxxxxxxxxxxxxxxx wrote:
> > > > On Mon, Apr 28, 2014 at 05:25:08PM -0700, Paul E. McKenney wrote:
> > > > > From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
> > > > > 
> > > > > Currently, torture_kthread_stopping() prints only the name of the
> > > > > kthread that is stopping, which can be unedifying.  This commit therefore
> > > > > adds "Stopping" to make things more evident.
> > > > > 
> > > > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> > > > 
> > > > Feedback below.
> > > > 
> > > > >  kernel/torture.c | 5 ++++-
> > > > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/kernel/torture.c b/kernel/torture.c
> > > > > index acc9afc2f26e..f329848c3eee 100644
> > > > > --- a/kernel/torture.c
> > > > > +++ b/kernel/torture.c
> > > > > @@ -674,8 +674,11 @@ EXPORT_SYMBOL_GPL(torture_must_stop_irq);
> > > > >   */
> > > > >  void torture_kthread_stopping(char *title)
> > > > >  {
> > > > > +	char buf[128];
> > > > > +
> > > > > +	snprintf(buf, sizeof(buf), "Stopping %s", title);
> > > > >  	if (verbose)
> > > > > -		VERBOSE_TOROUT_STRING(title);
> > > > > +		VERBOSE_TOROUT_STRING(buf);
> > > > 
> > > > This seems like a case where the macro has led to poorer code; rather
> > > > than using sprintf into a temporary buffer, this should just print.
> > > > Please consider fixing the output macros to allow formats, as the pr_*
> > > > macros do.
> > > > 
> > > > Also, why do you need "if (verbose)" if the name of the macro has
> > > > VERBOSE_ in it; shouldn't that mean it checks verbosity itself?
> > > > (Another good reason not to create a unique verbosity level mechanism,
> > > > and to use the kernel mechanisms instead.)
> > > 
> > > Good catch, removed the redundant "if (verbose)".
> > > 
> > > My attempts in the past to leverage existing in-kernel verbosity controls
> > > has caused problems such as the output appearing or not depending on
> > > the distro in question.
> > 
> > That aside, though, what do you think about making the macros accept
> > format strings and arguments, in the style of pr_* and pr_fmt?
> 
> If I end up needing this in a few more cases, then it would indeed be
> worth it.

I'd argue that it's worth it already: doing snprintf into a temporary
buffer seems ridiculous here, when without these macros you'd just call
pr_foo("Stopping %s\n", title);

- Josh Triplett
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/