Re: [PATCH 05/32] nohz: Move rcu dynticks idle mode handling to idle enter/exit APIs

Peter Zijlstra
2011-08-30T11:18:11Z

On Tue, 2011-08-30 at 01:35 +0200, Frederic Weisbecker wrote:
> But rcu read side critical sections (preemption disabled, rcu_read_lock(),
> softirq disabled) don't need the tick to enforce the critical section
> itself.

Note that with PREEMPT_RCU only the rcu_read_lock() is actually an rcu
read side critical section, non of the others should be used as such.
Relying on preempt_disable(), local_bh_disable() and similar is broken
as per a long while ago.