Hello, Quick question (for educational purpose) for anyone - why does PREEMPT=n kernel not want to get help from __rcu_read_unlock() for expedited grace periods? Basically, with PREEMPT=y kernels, rcu_read_unlock_special.b.exp_hint is set to true, but for PREEMPT=n, no such thing is done. Furthermore, the __rcu_read_unlock() for PREEMPT=n does not help expedited GPs come to an end either. I am guessing the answer is, "no one cares about that", or "no one reported needing this", but if there is another reason why a PREEMPT=n kernel should not need it, do let me know :) To make it more interesting, it appears that CONFIG_PREEMPT=y where preemption is dynamically disabled, it _should_ have the effect of helping expedited GPs as far as I can see. Which further seems a difference between booting PREEMPT=n versus PREEMPT=y + booting with preemption turned off via boot option. thanks, - Joel
