diff options
| -rw-r--r-- | kernel/rcu/tasks.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index a8f95864c921..d318cdfd2309 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1492,7 +1492,11 @@ static void rcu_tasks_trace_pertask_handler(void *hop_in) /* Initialize for a new RCU-tasks-trace grace period. */ static void rcu_tasks_trace_pregp_step(struct list_head *hop) { + LIST_HEAD(blkd_tasks); int cpu; + unsigned long flags; + struct rcu_tasks_percpu *rtpcp; + struct task_struct *t; // There shouldn't be any old IPIs, but... for_each_possible_cpu(cpu) @@ -1506,6 +1510,26 @@ static void rcu_tasks_trace_pregp_step(struct list_head *hop) // allow safe access to the hop list. for_each_online_cpu(cpu) smp_call_function_single(cpu, rcu_tasks_trace_pertask_handler, hop, 1); + + // Only after all running tasks have been accounted for is it + // safe to take care of the tasks that have blocked within their + // current RCU tasks trace read-side critical section. + for_each_possible_cpu(cpu) { + rtpcp = per_cpu_ptr(rcu_tasks_trace.rtpcpu, cpu); + raw_spin_lock_irqsave_rcu_node(rtpcp, flags); + list_splice_init(&rtpcp->rtp_blkd_tasks, &blkd_tasks); + while (!list_empty(&blkd_tasks)) { + rcu_read_lock(); + t = list_first_entry(&blkd_tasks, struct task_struct, trc_blkd_node); + list_del_init(&t->trc_blkd_node); + list_add(&t->trc_blkd_node, &rtpcp->rtp_blkd_tasks); + raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags); + rcu_tasks_trace_pertask(t, hop); + rcu_read_unlock(); + raw_spin_lock_irqsave_rcu_node(rtpcp, flags); + } + raw_spin_unlock_irqrestore_rcu_node(rtpcp, flags); + } } /* |