diff options
| -rw-r--r-- | kernel/rcutree.c | 54 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 11 |
2 files changed, 56 insertions, 9 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 77a7671dd147..89419ff92e99 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1648,7 +1648,6 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu) if (IS_ERR(t)) return PTR_ERR(t); kthread_bind(t, cpu); - set_task_state(t, TASK_INTERRUPTIBLE); per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu; WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL); per_cpu(rcu_cpu_kthread_task, cpu) = t; @@ -1756,7 +1755,6 @@ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp, if (IS_ERR(t)) return PTR_ERR(t); raw_spin_lock_irqsave(&rnp->lock, flags); - set_task_state(t, TASK_INTERRUPTIBLE); rnp->node_kthread_task = t; raw_spin_unlock_irqrestore(&rnp->lock, flags); sp.sched_priority = 99; @@ -1765,6 +1763,8 @@ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp, return rcu_spawn_one_boost_kthread(rsp, rnp, rnp_index); } +static void rcu_wake_one_boost_kthread(struct rcu_node *rnp); + /* * Spawn all kthreads -- called as soon as the scheduler is running. */ @@ -1772,18 +1772,30 @@ static int __init rcu_spawn_kthreads(void) { int cpu; struct rcu_node *rnp; + struct task_struct *t; rcu_kthreads_spawnable = 1; for_each_possible_cpu(cpu) { per_cpu(rcu_cpu_has_work, cpu) = 0; - if (cpu_online(cpu)) + if (cpu_online(cpu)) { (void)rcu_spawn_one_cpu_kthread(cpu); + t = per_cpu(rcu_cpu_kthread_task, cpu); + if (t) + wake_up_process(t); + } } rnp = rcu_get_root(rcu_state); (void)rcu_spawn_one_node_kthread(rcu_state, rnp); + if (rnp->node_kthread_task) + wake_up_process(rnp->node_kthread_task); if (NUM_RCU_NODES > 1) { - rcu_for_each_leaf_node(rcu_state, rnp) + rcu_for_each_leaf_node(rcu_state, rnp) { (void)rcu_spawn_one_node_kthread(rcu_state, rnp); + t = rnp->node_kthread_task; + if (t) + wake_up_process(t); + rcu_wake_one_boost_kthread(rnp); + } } return 0; } @@ -2188,14 +2200,14 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible) raw_spin_unlock_irqrestore(&rsp->onofflock, flags); } -static void __cpuinit rcu_online_cpu(int cpu) +static void __cpuinit rcu_prepare_cpu(int cpu) { rcu_init_percpu_data(cpu, &rcu_sched_state, 0); rcu_init_percpu_data(cpu, &rcu_bh_state, 0); rcu_preempt_init_percpu_data(cpu); } -static void __cpuinit rcu_online_kthreads(int cpu) +static void __cpuinit rcu_prepare_kthreads(int cpu) { struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu); struct rcu_node *rnp = rdp->mynode; @@ -2209,6 +2221,31 @@ static void __cpuinit rcu_online_kthreads(int cpu) } /* + * kthread_create() creates threads in TASK_UNINTERRUPTIBLE state, + * but the RCU threads are woken on demand, and if demand is low this + * could be a while triggering the hung task watchdog. + * + * In order to avoid this, poke all tasks once the CPU is fully + * up and running. + */ +static void __cpuinit rcu_online_kthreads(int cpu) +{ + struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu); + struct rcu_node *rnp = rdp->mynode; + struct task_struct *t; + + t = per_cpu(rcu_cpu_kthread_task, cpu); + if (t) + wake_up_process(t); + + t = rnp->node_kthread_task; + if (t) + wake_up_process(t); + + rcu_wake_one_boost_kthread(rnp); +} + +/* * Handle CPU online/offline notification events. */ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, @@ -2221,10 +2258,11 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self, switch (action) { case CPU_UP_PREPARE: case CPU_UP_PREPARE_FROZEN: - rcu_online_cpu(cpu); - rcu_online_kthreads(cpu); + rcu_prepare_cpu(cpu); + rcu_prepare_kthreads(cpu); break; case CPU_ONLINE: + rcu_online_kthreads(cpu); case CPU_DOWN_FAILED: rcu_node_kthread_setaffinity(rnp, -1); rcu_cpu_kthread_setrt(cpu, 1); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index a767b7dac365..c8bff3099a89 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1295,7 +1295,6 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, if (IS_ERR(t)) return PTR_ERR(t); raw_spin_lock_irqsave(&rnp->lock, flags); - set_task_state(t, TASK_INTERRUPTIBLE); rnp->boost_kthread_task = t; raw_spin_unlock_irqrestore(&rnp->lock, flags); sp.sched_priority = RCU_KTHREAD_PRIO; @@ -1303,6 +1302,12 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, return 0; } +static void __cpuinit rcu_wake_one_boost_kthread(struct rcu_node *rnp) +{ + if (rnp->boost_kthread_task) + wake_up_process(rnp->boost_kthread_task); +} + #else /* #ifdef CONFIG_RCU_BOOST */ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags) @@ -1326,6 +1331,10 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, return 0; } +static void __cpuinit rcu_wake_one_boost_kthread(struct rcu_node *rnp) +{ +} + #endif /* #else #ifdef CONFIG_RCU_BOOST */ #ifndef CONFIG_SMP |