Messages in this thread | | | Date | Tue, 27 Nov 2012 17:31:14 +0100 | Subject | Re: [RFC PATCH] Fix abnormal rcu dynticks_nesting values related to async page fault | From | Frederic Weisbecker <> |
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2012/11/27 Paul E. McKenney <paulmck@linux.vnet.ibm.com>: > It is OK to call rcu_irq_exit() without a matching rcu_irq_enter() -only- > if you have also called rcu_idle_exit() since the last rcu_idle_enter(). > There will be a similar rule for rcu_user_exit(). > > More generally, it is OK to call rcu_irq_exit() without a matching > rcu_irq_enter() only if RCU believes that the CPU you are running on is > non-idle.
Perfect!
> On 32-bit systems, you are only allowed a few tens of million > such unmatched rcu_irq_enter() calls in a given RCU-non-idle region. > > All courtesy of RCU's need to tolerate architectures that enter > interrupt handlers without ever leaving them and vice versa. ;-)
RCU idle mode in a hostile environment ;-)
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