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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2009-10-06 21:48:16 -0700
committerIngo Molnar <mingo@elte.hu>2009-10-07 08:11:20 +0200
commitd0ec774cb2599c858be9d923bb873cf6697520d8 (patch)
tree0897fd843622033a6db6ab43167e47c3236aa22d /kernel/rcupdate.c
parent322a2c100a8998158445599ea437fb556aa95b11 (diff)
downloadvexpress-lsk-d0ec774cb2599c858be9d923bb873cf6697520d8.tar.gz
rcu: Move rcu_barrier() to rcutree
Move the existing rcu_barrier() implementation to rcutree.c, consistent with the fact that the rcu_barrier() implementation is tied quite tightly to the RCU implementation. This opens the way to simplify and fix rcutree.c's rcu_barrier() implementation in a later patch. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12548908982563-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcupdate.c')
-rw-r--r--kernel/rcupdate.c120
1 files changed, 1 insertions, 119 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index e4324227446..400183346ad 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -53,16 +53,8 @@ struct lockdep_map rcu_lock_map =
EXPORT_SYMBOL_GPL(rcu_lock_map);
#endif
-static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
-static atomic_t rcu_barrier_cpu_count;
-static DEFINE_MUTEX(rcu_barrier_mutex);
-static struct completion rcu_barrier_completion;
int rcu_scheduler_active __read_mostly;
-static atomic_t rcu_migrate_type_count = ATOMIC_INIT(0);
-static struct rcu_head rcu_migrate_head[3];
-static DECLARE_WAIT_QUEUE_HEAD(rcu_migrate_wq);
-
/*
* Awaken the corresponding synchronize_rcu() instance now that a
* grace period has elapsed.
@@ -165,120 +157,10 @@ void synchronize_rcu_bh(void)
}
EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
-static void rcu_barrier_callback(struct rcu_head *notused)
-{
- if (atomic_dec_and_test(&rcu_barrier_cpu_count))
- complete(&rcu_barrier_completion);
-}
-
-/*
- * Called with preemption disabled, and from cross-cpu IRQ context.
- */
-static void rcu_barrier_func(void *type)
-{
- int cpu = smp_processor_id();
- struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu);
- void (*call_rcu_func)(struct rcu_head *head,
- void (*func)(struct rcu_head *head));
-
- atomic_inc(&rcu_barrier_cpu_count);
- call_rcu_func = type;
- call_rcu_func(head, rcu_barrier_callback);
-}
-
-static inline void wait_migrated_callbacks(void)
-{
- wait_event(rcu_migrate_wq, !atomic_read(&rcu_migrate_type_count));
- smp_mb(); /* In case we didn't sleep. */
-}
-
-/*
- * Orchestrate the specified type of RCU barrier, waiting for all
- * RCU callbacks of the specified type to complete.
- */
-static void _rcu_barrier(void (*call_rcu_func)(struct rcu_head *head,
- void (*func)(struct rcu_head *head)))
-{
- BUG_ON(in_interrupt());
- /* Take cpucontrol mutex to protect against CPU hotplug */
- mutex_lock(&rcu_barrier_mutex);
- init_completion(&rcu_barrier_completion);
- /*
- * Initialize rcu_barrier_cpu_count to 1, then invoke
- * rcu_barrier_func() on each CPU, so that each CPU also has
- * incremented rcu_barrier_cpu_count. Only then is it safe to
- * decrement rcu_barrier_cpu_count -- otherwise the first CPU
- * might complete its grace period before all of the other CPUs
- * did their increment, causing this function to return too
- * early.
- */
- atomic_set(&rcu_barrier_cpu_count, 1);
- on_each_cpu(rcu_barrier_func, (void *)call_rcu_func, 1);
- if (atomic_dec_and_test(&rcu_barrier_cpu_count))
- complete(&rcu_barrier_completion);
- wait_for_completion(&rcu_barrier_completion);
- mutex_unlock(&rcu_barrier_mutex);
- wait_migrated_callbacks();
-}
-
-/**
- * rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
- */
-void rcu_barrier(void)
-{
- _rcu_barrier(call_rcu);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier);
-
-/**
- * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
- */
-void rcu_barrier_bh(void)
-{
- _rcu_barrier(call_rcu_bh);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier_bh);
-
-/**
- * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
- */
-void rcu_barrier_sched(void)
-{
- _rcu_barrier(call_rcu_sched);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier_sched);
-
-static void rcu_migrate_callback(struct rcu_head *notused)
-{
- if (atomic_dec_and_test(&rcu_migrate_type_count))
- wake_up(&rcu_migrate_wq);
-}
-
static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
unsigned long action, void *hcpu)
{
- rcu_cpu_notify(self, action, hcpu);
- if (action == CPU_DYING) {
- /*
- * preempt_disable() in on_each_cpu() prevents stop_machine(),
- * so when "on_each_cpu(rcu_barrier_func, (void *)type, 1);"
- * returns, all online cpus have queued rcu_barrier_func(),
- * and the dead cpu(if it exist) queues rcu_migrate_callback()s.
- *
- * These callbacks ensure _rcu_barrier() waits for all
- * RCU callbacks of the specified type to complete.
- */
- atomic_set(&rcu_migrate_type_count, 3);
- call_rcu_bh(rcu_migrate_head, rcu_migrate_callback);
- call_rcu_sched(rcu_migrate_head + 1, rcu_migrate_callback);
- call_rcu(rcu_migrate_head + 2, rcu_migrate_callback);
- } else if (action == CPU_DOWN_PREPARE) {
- /* Don't need to wait until next removal operation. */
- /* rcu_migrate_head is protected by cpu_add_remove_lock */
- wait_migrated_callbacks();
- }
-
- return NOTIFY_OK;
+ return rcu_cpu_notify(self, action, hcpu);
}
void __init rcu_init(void)