diff options
| -rw-r--r-- | kernel/rcu/tasks.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index c61dc92537db..147b5945d67a 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -968,13 +968,33 @@ static void rcu_tasks_postscan(struct list_head *hop) */ for_each_possible_cpu(cpu) { + unsigned long j = jiffies + 1; struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rcu_tasks.rtpcpu, cpu); struct task_struct *t; + struct task_struct *t1; + struct list_head tmp; raw_spin_lock_irq_rcu_node(rtpcp); - list_for_each_entry(t, &rtpcp->rtp_exit_list, rcu_tasks_exit_list) + list_for_each_entry_safe(t, t1, &rtpcp->rtp_exit_list, rcu_tasks_exit_list) { if (list_empty(&t->rcu_tasks_holdout_list)) rcu_tasks_pertask(t, hop); + + // RT kernels need frequent pauses, otherwise + // pause at least once per pair of jiffies. + if (!IS_ENABLED(CONFIG_PREEMPT_RT) && time_before(jiffies, j)) + continue; + + // Keep our place in the list while pausing. + // Nothing else traverses this list, so adding a + // bare list_head is OK. + list_add(&tmp, &t->rcu_tasks_exit_list); + raw_spin_unlock_irq_rcu_node(rtpcp); + cond_resched(); // For CONFIG_PREEMPT=n kernels + raw_spin_lock_irq_rcu_node(rtpcp); + t1 = list_entry(tmp.next, struct task_struct, rcu_tasks_exit_list); + list_del(&tmp); + j = jiffies + 1; + } raw_spin_unlock_irq_rcu_node(rtpcp); } |