Messages in this thread Patch in this message | | | Date | Sat, 06 Sep 2008 18:37:38 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH, RFC] v4 scalable classic RCU implementation |
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Hi Paul,
Paul E. McKenney wrote: > o The rcu_pending() and rcu_needs_cpu() primitives are now > much more aggressive about permitting CPUs to enter dynticks > idle mode. Only CPUs that have RCU callbacks are kept out > of dynticks idle mode. >
I've noticed that right now rcu_enter_nohz() can be nested within rcu_irq_enter(): irq_exit() first calls tick_nohz_stop_sched_tick(), then rcu_irq_exit(). And tick_nohz_stop_sched_tick() can switch into nohz mode.
Is that intentional? Does rcupreempt support that? It broke my rcustate code on x86-64.
I would prefer if something like the attached patch is applied. What do you think? Do you need the patch as well?
-- Manfred diff --git a/kernel/softirq.c b/kernel/softirq.c index ba20a90..cca5a83 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -284,10 +284,10 @@ void irq_exit(void) invoke_softirq(); #ifdef CONFIG_NO_HZ + rcu_irq_exit(0); /* Make sure that timer wheel updates are propagated */ if (!in_interrupt() && idle_cpu(smp_processor_id()) && !need_resched()) tick_nohz_stop_sched_tick(0); - rcu_irq_exit(0); #endif preempt_enable_no_resched(); } | |