Messages in this thread | | | Date | Tue, 26 Feb 2013 11:17:58 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 2/2] irq: Cleanup context state transitions in irq_exit() |
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On Tue, Feb 26, 2013 at 07:55:06PM +0100, Thomas Gleixner wrote: > On Tue, 26 Feb 2013, Paul E. McKenney wrote: > > On Tue, Feb 26, 2013 at 04:14:43PM +0100, Thomas Gleixner wrote: > > > > > > On Tue, 26 Feb 2013, Frederic Weisbecker wrote: > > > > And what do you think about Linus's idea to move tick_nohz_irq_exit() > > > > to do_softirq()? > > > > This sounds feasible and a right place to do this, I hope that won't > > > > uglify do_softirq() though. > > > > I can try something. > > > > > > Yeah, looks doable. the rcu stuff needs to go there as well, right? > > > > If it does, it needs to do so in such a way that rcu_irq_enter() and > > rcu_irq_exit() nest properly. One area of concern is the force_irqthreads > > case, skips calling do_softirq(). Another area of concern is the > > __ARCH_IRQ_EXIT_IRQS_DISABLED case, which calls __do_softirq() rather > > than do_softirq(). > > That's sorted already. We disable interrupts in irq_exit(). > > > Or am I missing some adjustment that is to be made when moving rcu_irq_exit() > > to do_softirq()? > > Yeah, we need an extra parameter or such, so the other callers of > __do_softirq() don't mess with it. > > I also noticed that rcu_irq_enter/exit needs to be symetric and the > NOHZ code will get confused as well if we call it asymetric.
Exactly!
Thanx, Paul
> So that will become even more ugly than the extra check at the end of > irq_exit(). > > Thanks, > > tglx > > >
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