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Viewing changes to kernel/rcupdate.c

  • Committer: Bazaar Package Importer
  • Author(s): Luke Yelavich
  • Date: 2009-08-05 23:00:52 UTC
  • Revision ID: james.westby@ubuntu.com-20090805230052-7xedvqcyk9dnnxb2
Tags: 2.6.31-1.1
New upstream release

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Lines of Context:
kernel/rcupdate.c
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static struct completion rcu_barrier_completion;
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int rcu_scheduler_active __read_mostly;
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static atomic_t rcu_migrate_type_count = ATOMIC_INIT(0);
 
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static struct rcu_head rcu_migrate_head[3];
 
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static DECLARE_WAIT_QUEUE_HEAD(rcu_migrate_wq);
 
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/*
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 * Awaken the corresponding synchronize_rcu() instance now that a
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 * grace period has elapsed.
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        }
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}
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static inline void wait_migrated_callbacks(void)
 
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{
 
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        wait_event(rcu_migrate_wq, !atomic_read(&rcu_migrate_type_count));
 
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}
 
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/*
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 * Orchestrate the specified type of RCU barrier, waiting for all
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 * RCU callbacks of the specified type to complete.
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                complete(&rcu_barrier_completion);
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        wait_for_completion(&rcu_barrier_completion);
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        mutex_unlock(&rcu_barrier_mutex);
 
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        wait_migrated_callbacks();
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}
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/**
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}
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EXPORT_SYMBOL_GPL(rcu_barrier_sched);
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static void rcu_migrate_callback(struct rcu_head *notused)
 
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{
 
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        if (atomic_dec_and_test(&rcu_migrate_type_count))
 
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                wake_up(&rcu_migrate_wq);
 
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}
 
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static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
 
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                unsigned long action, void *hcpu)
 
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{
 
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        if (action == CPU_DYING) {
 
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                /*
 
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                 * preempt_disable() in on_each_cpu() prevents stop_machine(),
 
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                 * so when "on_each_cpu(rcu_barrier_func, (void *)type, 1);"
 
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                 * returns, all online cpus have queued rcu_barrier_func(),
 
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                 * and the dead cpu(if it exist) queues rcu_migrate_callback()s.
 
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                 *
 
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                 * These callbacks ensure _rcu_barrier() waits for all
 
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                 * RCU callbacks of the specified type to complete.
 
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                 */
 
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                atomic_set(&rcu_migrate_type_count, 3);
 
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                call_rcu_bh(rcu_migrate_head, rcu_migrate_callback);
 
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                call_rcu_sched(rcu_migrate_head + 1, rcu_migrate_callback);
 
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                call_rcu(rcu_migrate_head + 2, rcu_migrate_callback);
 
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        } else if (action == CPU_POST_DEAD) {
 
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                /* rcu_migrate_head is protected by cpu_add_remove_lock */
 
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                wait_migrated_callbacks();
 
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        }
 
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        return NOTIFY_OK;
 
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}
 
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void __init rcu_init(void)
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{
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        __rcu_init();
 
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        hotcpu_notifier(rcu_barrier_cpu_hotplug, 0);
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}
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void rcu_scheduler_starting(void)