[PATCH 3/3] rcu: Use rcu_num_nodes instead of NUM_RCU_NODES

From: Pranith Kumar
Date: Tue Jul 15 2014 - 18:31:38 EST


NUM_RCU_NODES is set at build time and is usually a huge number. We calculate the
actual number of rcu nodes necessary at boot time based on nr_cpu_ids in
rcu_init_geometry() and store it in rcu_num_nodes. We should use this variable
instead of NUM_RCU_NODES.

This commit changes all such uses of NUM_RCU_NODES to rcu_num_nodes.

Signed-off-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
---
kernel/rcu/tree_plugin.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index cedb020..17ccb62 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -46,6 +46,8 @@ static bool __read_mostly rcu_nocb_poll; /* Offload kthread are to poll. */
static char __initdata nocb_buf[NR_CPUS * 5];
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */

+extern int rcu_num_nodes;
+
/*
* Check the RCU kernel configuration parameters and print informative
* messages about anything out of the ordinary. If you like #ifdef, you
@@ -885,7 +887,7 @@ void synchronize_rcu_expedited(void)
/* Snapshot current state of ->blkd_tasks lists. */
rcu_for_each_leaf_node(rsp, rnp)
sync_rcu_preempt_exp_init(rsp, rnp);
- if (NUM_RCU_NODES > 1)
+ if (rcu_num_nodes > 1)
sync_rcu_preempt_exp_init(rsp, rcu_get_root(rsp));

put_online_cpus();
@@ -1475,7 +1477,7 @@ static void __init rcu_spawn_boost_kthreads(void)
BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
rnp = rcu_get_root(rcu_state_p);
(void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
- if (NUM_RCU_NODES > 1) {
+ if (rcu_num_nodes > 1) {
rcu_for_each_leaf_node(rcu_state_p, rnp)
(void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
}
--
1.9.1

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