Re: [PATCH 01/13] powerpc: Add rcu_read_lock() to gup_fast() implementation

Benjamin Herrenschmidt
2010-04-16T07:25:45Z

On Thu, 2010-04-15 at 07:28 -0700, Paul E. McKenney wrote:
>
> Of course, with call_rcu_sched(), the corresponding RCU read-side
> critical
> sections are non-preemptible. Therefore, in CONFIG_PREEMPT_RT, these
> read-side critical sections must use raw spinlocks.
>
> Can the code in question accommodate these restrictions?

What we protect against is always code that hard-disable IRQs (though
there seem to be a bug in the hugepages code there...). Would that
work ?

Cheers,
Ben.