diff options
| -rw-r--r-- | kernel/rcu/tree_exp.h | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 8a1d9c8bd9f7..1dbad2442e8d 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -357,7 +357,21 @@ static void __sync_rcu_exp_select_node_cpus(struct rcu_exp_work *rewp) !(rnp->qsmaskinitnext & mask)) { mask_ofl_test |= mask; } else { - snap = rcu_dynticks_snap(cpu); + /* + * Full ordering between remote CPU's post idle accesses + * and updater's accesses prior to current GP (and also + * the started GP sequence number) is enforced by + * rcu_seq_start() implicit barrier, relayed by kworkers + * locking and even further by smp_mb__after_unlock_lock() + * barriers chained all the way throughout the rnp locking + * tree since sync_exp_reset_tree() and up to the current + * leaf rnp locking. + * + * Ordering between remote CPU's pre idle accesses and + * post grace period updater's accesses is enforced by the + * below acquire semantic. + */ + snap = ct_dynticks_cpu_acquire(cpu); if (rcu_dynticks_in_eqs(snap)) mask_ofl_test |= mask; else |