Re: [PATCH RFC idle] Make arm, sh, and x86 stop using RCU when idle

From: Paul E. McKenney
Date: Wed Feb 01 2012 - 20:15:05 EST

On Wed, Feb 01, 2012 at 04:48:29PM -0800, Josh Triplett wrote:
> On Wed, Feb 01, 2012 at 04:42:53PM -0800, Paul E. McKenney wrote:
> > RCU's shiny new diagnostics (thank you, Frederic!) for using RCU when idle
> > located a few problems in arm, sh, and x86. This patch series contains
> > alleged fixes for these problems. And they are real problems -- if RCU
> > believes that the CPU is idle, it is ignoring it. Which means that the
> > idle CPU can say "rcu_read_lock()" all it like, but there will be no
> > useful effect.
> Having to put these calls down in every idle driver seems like such an
> ugly layering violation. Not that I have a better alternative to
> suggest...

If you do happen to think of one, I would very much like to hear of it! ;-)

Thanx, Paul

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