Re: [PATCH 2/6] rcu: Create rcu_sync infrastructure

[Srikar Dronamraju]

* Peter Zijlstra <peterz@xxxxxxxxxxxxx> [2013-10-08 12:25:07]:

> From: Oleg Nesterov <oleg@xxxxxxxxxx>
> 
> It is functionally equivalent to
> 
>         struct rcu_sync_struct {
>                 atomic_t counter;
>         };
> 
>         static inline bool rcu_sync_is_idle(struct rcu_sync_struct *xxx)
>         {
>                 return atomic_read(&xxx->counter) == 0;
>         }
> 
>         static inline void rcu_sync_enter(struct rcu_sync_struct *xxx)
>         {
>                 atomic_inc(&xxx->counter);
>                 synchronize_sched();
>         }
> 
>         static inline void rcu_sync_enter(struct rcu_sync_struct *xxx)

Guess you meant rcu_sync_exit

>         {
>                 synchronize_sched();
>                 atomic_dec(&xxx->counter);
>         }
> 
> except: it records the state and synchronize_sched() is only called by
> rcu_sync_enter() and only if necessary.
> 

-- 
Thanks and Regards
Srikar Dronamraju

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