rcu: Allow processing deferred QSes for exiting RCU-preempt readers

If an RCU-preempt read-side critical section is exiting, that is,
->rcu_read_lock_nesting is negative, then it is a good time to look
at the possibility of reporting deferred quiescent states.  This
commit therefore updates the checks in rcu_preempt_need_deferred_qs()
to allow exiting critical sections to report deferred quiescent states.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-06-27 21:48:00 -07:00
parent c0335743c5
commit 27c744e32a

View file

@ -602,7 +602,7 @@ static bool rcu_preempt_need_deferred_qs(struct task_struct *t)
{
return (this_cpu_ptr(&rcu_preempt_data)->deferred_qs ||
READ_ONCE(t->rcu_read_unlock_special.s)) &&
!t->rcu_read_lock_nesting;
t->rcu_read_lock_nesting <= 0;
}
/*