diff options
Diffstat (limited to 'kernel/sched/core.c')
| -rw-r--r-- | kernel/sched/core.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fa0d4990618e..b71ed5ee97fd 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2275,13 +2275,21 @@ static int ttwu_remote(struct task_struct *p, int wake_flags) void sched_ttwu_pending(void) { struct rq *rq = this_rq(); - struct llist_node *llist = llist_del_all(&rq->wake_list); + struct llist_node *llist; struct task_struct *p, *t; struct rq_flags rf; + llist = llist_del_all(&rq->wake_list); if (!llist) return; + /* + * rq::ttwu_pending racy indication of out-standing wakeups. + * Races such that false-negatives are possible, since they + * are shorter lived that false-positives would be. + */ + WRITE_ONCE(rq->ttwu_pending, 0); + rq_lock_irqsave(rq, &rf); update_rq_clock(rq); @@ -2318,6 +2326,7 @@ static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED); + WRITE_ONCE(rq->ttwu_pending, 1); if (llist_add(&p->wake_entry, &rq->wake_list)) { if (!set_nr_if_polling(rq->idle)) smp_call_function_single_async(cpu, &rq->wake_csd); @@ -4705,7 +4714,7 @@ int idle_cpu(int cpu) return 0; #ifdef CONFIG_SMP - if (!llist_empty(&rq->wake_list)) + if (rq->ttwu_pending) return 0; #endif |