On 20/10/21 13:17, Peter Zijlstra wrote:
AFAICT, rcu_read_lock() for PREEMPT_RCU is: WRITE_ONCE(current->rcu_read_lock_nesting, READ_ONCE(current->rcu_read_lock_nesting) + 1); barrier();
rcu_read_unlock() is the expensive one if you need to go down rcu_read_unlock_special().
Paolo
Paul?
