Re: [PATCH tip/core/rcu 09/15] rcu: Increasing rcu_barrier()concurrency

From: Paul E. McKenney
Date: Fri Jun 15 2012 - 20:49:32 EST


On Fri, Jun 15, 2012 at 08:21:20PM -0400, Steven Rostedt wrote:
> On Fri, 2012-06-15 at 16:31 -0700, Josh Triplett wrote:
> >
> > > - smp_mb(); /* Prevent any prior operations from leaking in. */
> > > + /*
> > > + * Ensure tht all prior references, including to ->n_barrier_done,
> > > + * are ordered before the _rcu_barrier() machinery.
> > > + */
> > > + smp_mb(); /* See above block comment. */
> >
> > If checkpatch complains about the lack of a comment to the right of a
> > barrier even when the barrier has a comment directly above it, that
> > seems like a bug in checkpatch that needs fixing, to prevent developers
> > from having to add noise like "See above block comment.". :)
>
>
> Yuck yuck yuck yuck!!!
>
>
> Really, checkpatch is not the golden rule. I've copied an old checkpatch
> from something like 2.6.38 or so and use that today, where it was still
> reasonable. I've long abandoned the latest checkpatch, as it causes too
> many false positives. Or nazis like dictation.
>
> My rule of thumb is this. If what checkpatch tells you to do makes the
> format either uglier, or look stupid, it's a good idea to ignore the
> checkpatch complaint.
>
> I think in this case, you hit the latter.

Heh. I have been doing this "/* See above block comment. */" thing for
quite some time. ;-)

Thanx, Paul

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