diff options
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b7d943e98a9a..da5718da280d 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -777,7 +777,18 @@ static void rcu_gpnum_ovf(struct rcu_node *rnp, struct rcu_data *rdp) */ static int dyntick_save_progress_counter(struct rcu_data *rdp) { - rdp->dynticks_snap = rcu_dynticks_snap(rdp->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 and even further by + * smp_mb__after_unlock_lock() barriers chained all the way throughout the + * rnp locking tree since rcu_gp_init() 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. + */ + rdp->dynticks_snap = ct_dynticks_cpu_acquire(rdp->cpu); if (rcu_dynticks_in_eqs(rdp->dynticks_snap)) { trace_rcu_fqs(rcu_state.name, rdp->gp_seq, rdp->cpu, TPS("dti")); rcu_gpnum_ovf(rdp->mynode, rdp); |