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

From: Peter Zijlstra
Date: Fri May 03 2013 - 14:11:07 EST


> This happens in only two cases:
>
> 1. CONFIG_PREEMPT_RCU=n kernels. But in this case, rcu_read_unlock()
> and rcu_read_lock() are free, at least for CONFIG_PROVE_LOCKING=n
> kernels. And if you have CONFIG_PROVE_LOCKING=y, any contribution
> from rcu_read_unlock() and rcu_read_lock() will be in the noise.

Oh argh.. I completely overlooked that rcu_read_{,un}lock() are NOPs for
PREEMPT=n kernels.

/me crawls back under his stone..
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