Re: [PATCH tip/core/rcu 0/6] Check for use of RCU from dyntick-idlemode

[Frederic Weisbecker]

On Fri, Jul 08, 2011 at 08:43:31AM -0700, Paul E. McKenney wrote:
> Hello!
> 
> This set of patches adds checks for use of RCU from "extended quiescent
> states" such as dyntick-idle mode.  Such use is grossly illegal because
> RCU by definition ignores CPUs that are in extended quiescent states.
> In the case of dyntick-idle mode, the only way for RCU to avoid ignoring
> such CPUs would be to wake them up periodically, which would defeat the
> whole purpose of dyntick-idle mode.
> 
> The good news is that Frederic got this effort started.  The bad news is
> that there are several cases where RCU read-side critical sections appear
> in dyntick-idle mode.

Ok, let me send to you the patch that splits up rcu/tickless logic and I'll try
to fix up what you reported to me in ppc.

BTW, are you aware of other cases? You mentioned "several" :)
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