diff options
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8a62cbfe1f2f..082aedefe29c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1611,15 +1611,23 @@ static int rcu_future_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp) } /* - * Awaken the grace-period kthread for the specified flavor of RCU. - * Don't do a self-awaken, and don't bother awakening when there is - * nothing for the grace-period kthread to do (as in several CPUs - * raced to awaken, and we lost), and finally don't try to awaken - * a kthread that has not yet been created. + * Awaken the grace-period kthread. Don't do a self-awaken (unless in + * an interrupt or softirq handler), and don't bother awakening when there + * is nothing for the grace-period kthread to do (as in several CPUs raced + * to awaken, and we lost), and finally don't try to awaken a kthread that + * has not yet been created. If all those checks are passed, track some + * debug information and awaken. + * + * So why do the self-wakeup when in an interrupt or softirq handler + * in the grace-period kthread's context? Because the kthread might have + * been interrupted just as it was going to sleep, and just after the final + * pre-sleep check of the awaken condition. In this case, a wakeup really + * is required, and is therefore supplied. */ static void rcu_gp_kthread_wake(struct rcu_state *rsp) { - if (current == rsp->gp_kthread || + if ((current == rsp->gp_kthread && + !in_interrupt() && !in_serving_softirq()) || !READ_ONCE(rsp->gp_flags) || !rsp->gp_kthread) return; @@ -3817,7 +3825,7 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) continue; rdp = per_cpu_ptr(rsp->rda, cpu); pr_cont(" %d-%c%c%c", cpu, - "O."[cpu_online(cpu)], + "O."[!!cpu_online(cpu)], "o."[!!(rdp->grpmask & rnp->expmaskinit)], "N."[!!(rdp->grpmask & rnp->expmaskinitnext)]); } |