Re: [PATCH RFC tip/core/rcu 7/7] rcu: Quiet RCU-lockdep warningsinvolving interrupt disabling

From: Steven Rostedt
Date: Tue Dec 06 2011 - 11:56:44 EST


On Tue, 2011-12-06 at 08:04 -0800, Paul E. McKenney wrote:

> > Perhaps the real answer is that we need to create an API for priority
> > inheritance, that things like RCU could use. Attach a task that another
> > task requires to finish something and boost the priority of that task.
> > Maybe even completions could use such a thing?
>
> I would be OK with that -- that was in fact the approach I was taking
> when I was advised to use mutexes instead. ;-)

Maybe we should rethink it. Using the makeshift mutex looks to be a
short term hack. But if we are starting to build on it, it will end up
being a horrible design, based off of a hack.

A mutex is to provide mutual exclusion. If we start bastardizing it to
do other things, it will become unmaintainable. I dare say that it's
close to unmaintainable now ;)

If we create a new API to handle inheritance, then perhaps it could be
used for other things like workqueues and completions (in -rt only).

-- Steve


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