doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist

This commit explains why rcu_read_lock_sched is better than using
preempt_disable.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
This commit is contained in:
Joel Fernandes (Google) 2018-10-05 16:18:11 -07:00 committed by Paul E. McKenney
parent 3398496483
commit 090c1685fd

View File

@ -63,7 +63,7 @@ over a rather long period of time, but improvements are always welcome!
pointer must be covered by rcu_read_lock(), rcu_read_lock_bh(),
rcu_read_lock_sched(), or by the appropriate update-side lock.
Disabling of preemption can serve as rcu_read_lock_sched(), but
is less readable.
is less readable and prevents lockdep from detecting locking issues.
Letting RCU-protected pointers "leak" out of an RCU read-side
critical section is every bid as bad as letting them leak out