Commit-ID: f4ecea309d3e17ba5e90082308125ad23bd5701b
Gitweb: http://git.kernel.org/tip/f4ecea309d3e17ba5e90082308125ad23bd5701b
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Wed, 29 Jul 2015 17:28:11 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 20 Sep 2015 21:16:17 -0700
rcu: Use rsp->expedited_wq instead of sync_rcu_preempt_exp_wq
Now that there is an ->expedited_wq waitqueue in each rcu_state structure,
there is no need for the sync_rcu_preempt_exp_wq global variable. This
commit therefore substitutes ->expedited_wq for sync_rcu_preempt_exp_wq.
It also initializes ->expedited_wq only once at boot instead of at the
start of each expedited grace period.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 2 +-
kernel/rcu/tree_plugin.h | 6 ++----
2 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 775d36c..53d66eb 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3556,7 +3556,6 @@ void synchronize_sched_expedited(void)
rcu_exp_gp_seq_start(rsp);
/* Stop each CPU that is online, non-idle, and not us. */
- init_waitqueue_head(&rsp->expedited_wq);
atomic_set(&rsp->expedited_need_qs, 1); /* Extra count avoids race. */
for_each_online_cpu(cpu) {
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
@@ -4179,6 +4178,7 @@ static void __init rcu_init_one(struct rcu_state *rsp,
}
init_waitqueue_head(&rsp->gp_wq);
+ init_waitqueue_head(&rsp->expedited_wq);
rnp = rsp->level[rcu_num_lvls - 1];
for_each_possible_cpu(i) {
while (i > rnp->grphi)
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index b2bf396..72df006 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -535,8 +535,6 @@ void synchronize_rcu(void)
}
EXPORT_SYMBOL_GPL(synchronize_rcu);
-static DECLARE_WAIT_QUEUE_HEAD(sync_rcu_preempt_exp_wq);
-
/*
* Return non-zero if there are any tasks in RCU read-side critical
* sections blocking the current preemptible-RCU expedited grace period.
@@ -590,7 +588,7 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
raw_spin_unlock_irqrestore(&rnp->lock, flags);
if (wake) {
smp_mb(); /* EGP done before wake_up(). */
- wake_up(&sync_rcu_preempt_exp_wq);
+ wake_up(&rsp->expedited_wq);
}
break;
}
@@ -729,7 +727,7 @@ void synchronize_rcu_expedited(void)
/* Wait for snapshotted ->blkd_tasks lists to drain. */
rnp = rcu_get_root(rsp);
- wait_event(sync_rcu_preempt_exp_wq,
+ wait_event(rsp->expedited_wq,
sync_rcu_preempt_exp_done(rnp));
/* Clean up and exit. */
--
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