diff options
Diffstat (limited to 'kernel/rcu/tasks.h')
| -rw-r--r-- | kernel/rcu/tasks.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 4dc56b6e27c0..ba3440a45b6d 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1747,6 +1747,16 @@ static void rcu_tasks_trace_pregp_step(struct list_head *hop) // allow safe access to the hop list. for_each_online_cpu(cpu) { rcu_read_lock(); + // Note that cpu_curr_snapshot() picks up the target + // CPU's current task while its runqueue is locked with + // an smp_mb__after_spinlock(). This ensures that either + // the grace-period kthread will see that task's read-side + // critical section or the task will see the updater's pre-GP + // accesses. The trailing smp_mb() in cpu_curr_snapshot() + // does not currently play a role other than simplify + // that function's ordering semantics. If these simplified + // ordering semantics continue to be redundant, that smp_mb() + // might be removed. t = cpu_curr_snapshot(cpu); if (rcu_tasks_trace_pertask_prep(t, true)) trc_add_holdout(t, hop); |