Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: Cure load woes
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07ef3c3b44
@ -1648,7 +1648,6 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu)
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if (IS_ERR(t))
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return PTR_ERR(t);
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kthread_bind(t, cpu);
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set_task_state(t, TASK_INTERRUPTIBLE);
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per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu;
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WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL);
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per_cpu(rcu_cpu_kthread_task, cpu) = t;
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@ -1756,7 +1755,6 @@ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp,
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if (IS_ERR(t))
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return PTR_ERR(t);
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raw_spin_lock_irqsave(&rnp->lock, flags);
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set_task_state(t, TASK_INTERRUPTIBLE);
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rnp->node_kthread_task = t;
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raw_spin_unlock_irqrestore(&rnp->lock, flags);
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sp.sched_priority = 99;
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@ -1765,6 +1763,8 @@ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp,
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return rcu_spawn_one_boost_kthread(rsp, rnp, rnp_index);
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}
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static void rcu_wake_one_boost_kthread(struct rcu_node *rnp);
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/*
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* Spawn all kthreads -- called as soon as the scheduler is running.
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*/
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@ -1772,18 +1772,30 @@ static int __init rcu_spawn_kthreads(void)
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{
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int cpu;
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struct rcu_node *rnp;
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struct task_struct *t;
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rcu_kthreads_spawnable = 1;
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for_each_possible_cpu(cpu) {
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per_cpu(rcu_cpu_has_work, cpu) = 0;
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if (cpu_online(cpu))
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if (cpu_online(cpu)) {
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(void)rcu_spawn_one_cpu_kthread(cpu);
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t = per_cpu(rcu_cpu_kthread_task, cpu);
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if (t)
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wake_up_process(t);
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}
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}
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rnp = rcu_get_root(rcu_state);
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(void)rcu_spawn_one_node_kthread(rcu_state, rnp);
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if (rnp->node_kthread_task)
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wake_up_process(rnp->node_kthread_task);
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if (NUM_RCU_NODES > 1) {
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rcu_for_each_leaf_node(rcu_state, rnp)
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rcu_for_each_leaf_node(rcu_state, rnp) {
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(void)rcu_spawn_one_node_kthread(rcu_state, rnp);
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t = rnp->node_kthread_task;
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if (t)
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wake_up_process(t);
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rcu_wake_one_boost_kthread(rnp);
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}
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}
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return 0;
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}
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@ -2188,14 +2200,14 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible)
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raw_spin_unlock_irqrestore(&rsp->onofflock, flags);
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}
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static void __cpuinit rcu_online_cpu(int cpu)
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static void __cpuinit rcu_prepare_cpu(int cpu)
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{
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rcu_init_percpu_data(cpu, &rcu_sched_state, 0);
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rcu_init_percpu_data(cpu, &rcu_bh_state, 0);
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rcu_preempt_init_percpu_data(cpu);
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}
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static void __cpuinit rcu_online_kthreads(int cpu)
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static void __cpuinit rcu_prepare_kthreads(int cpu)
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{
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struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
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struct rcu_node *rnp = rdp->mynode;
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@ -2208,6 +2220,31 @@ static void __cpuinit rcu_online_kthreads(int cpu)
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}
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}
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/*
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* kthread_create() creates threads in TASK_UNINTERRUPTIBLE state,
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* but the RCU threads are woken on demand, and if demand is low this
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* could be a while triggering the hung task watchdog.
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*
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* In order to avoid this, poke all tasks once the CPU is fully
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* up and running.
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*/
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static void __cpuinit rcu_online_kthreads(int cpu)
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{
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struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
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struct rcu_node *rnp = rdp->mynode;
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struct task_struct *t;
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t = per_cpu(rcu_cpu_kthread_task, cpu);
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if (t)
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wake_up_process(t);
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t = rnp->node_kthread_task;
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if (t)
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wake_up_process(t);
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rcu_wake_one_boost_kthread(rnp);
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}
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/*
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* Handle CPU online/offline notification events.
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*/
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@ -2221,10 +2258,11 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
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switch (action) {
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case CPU_UP_PREPARE:
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case CPU_UP_PREPARE_FROZEN:
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rcu_online_cpu(cpu);
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rcu_online_kthreads(cpu);
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rcu_prepare_cpu(cpu);
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rcu_prepare_kthreads(cpu);
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break;
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case CPU_ONLINE:
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rcu_online_kthreads(cpu);
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case CPU_DOWN_FAILED:
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rcu_node_kthread_setaffinity(rnp, -1);
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rcu_cpu_kthread_setrt(cpu, 1);
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@ -1295,7 +1295,6 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
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if (IS_ERR(t))
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return PTR_ERR(t);
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raw_spin_lock_irqsave(&rnp->lock, flags);
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set_task_state(t, TASK_INTERRUPTIBLE);
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rnp->boost_kthread_task = t;
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raw_spin_unlock_irqrestore(&rnp->lock, flags);
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sp.sched_priority = RCU_KTHREAD_PRIO;
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@ -1303,6 +1302,12 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
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return 0;
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}
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static void __cpuinit rcu_wake_one_boost_kthread(struct rcu_node *rnp)
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{
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if (rnp->boost_kthread_task)
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wake_up_process(rnp->boost_kthread_task);
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}
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#else /* #ifdef CONFIG_RCU_BOOST */
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static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
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@ -1326,6 +1331,10 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
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return 0;
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}
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static void __cpuinit rcu_wake_one_boost_kthread(struct rcu_node *rnp)
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{
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}
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#endif /* #else #ifdef CONFIG_RCU_BOOST */
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#ifndef CONFIG_SMP
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