Re: [PATCH v2 1/2] sched: Add cond_resched_rcu_lock() helper

[Julian Anastasov <ja@xxxxxx>]

        Hello,

On Fri, 3 May 2013, Paul E. McKenney wrote:

> static inline int cond_resched_rcu(void)
> {
> #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
>       rcu_read_unlock();
>       cond_resched();
>       rcu_read_lock();
> #endif
> }
> 
> This adds absolutely no overhead in non-debug builds of CONFIG_PREEMPT_RCU,
> does the checking in debug builds, and allows voluntary preemption in
> !CONFIG_PREEMPT_RCU builds.  CONFIG_PROVE_RCU builds will check for an
> (illegal) outer rcu_read_lock() in CONFIG_PREEMPT_RCU builds, and you
> will get "scheduling while atomic" in response to an outer rcu_read_lock()
> in !CONFIG_PREEMPT_RCU builds.
> 
> It also seems to me a lot simpler.
> 
> Does this work, or am I still missing something?

        Works perfectly. Thanks! Tested CONFIG_PREEMPT_RCU=y/n,
the errors messages with extra RCU lock.

Regards

--
Julian Anastasov <ja@xxxxxx>
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