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Subject[PATCH 1/1] rcu: Remove redundant checks for rcu_scheduler_fully_active
Date
rcu_scheduler_fully_active is set to true early in the boot process.

rcu_prepare_kthreads() is called in two locations. Once after setting the above
flag and the other while hotplugging a CPU from rcu_cpu_notify(). CPU hotplug is
enabled much later by which time the above flag is already set. Hence checking
for this flag is redundant in this function.

The checks in rcu_spawn_one_boost_kthread() and rcu_spawn_all_nocb_kthreads()
are similarly redundant.

This commit removes the redundant checks for this flag from the above
locations.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
kernel/rcu/tree_plugin.h | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 17ccb62..a2113f6 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1341,7 +1341,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
if (&rcu_preempt_state != rsp)
return 0;

- if (!rcu_scheduler_fully_active || rnp->qsmaskinit == 0)
+ if (rnp->qsmaskinit == 0)
return 0;

rsp->boost = 1;
@@ -1489,8 +1489,7 @@ static void rcu_prepare_kthreads(int cpu)
struct rcu_node *rnp = rdp->mynode;

/* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */
- if (rcu_scheduler_fully_active)
- (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
+ (void)rcu_spawn_one_boost_kthread(rcu_state_p, rnp);
}

#else /* #ifdef CONFIG_RCU_BOOST */
@@ -2509,9 +2508,8 @@ static void rcu_spawn_all_nocb_kthreads(int cpu)
{
struct rcu_state *rsp;

- if (rcu_scheduler_fully_active)
- for_each_rcu_flavor(rsp)
- rcu_spawn_one_nocb_kthread(rsp, cpu);
+ for_each_rcu_flavor(rsp)
+ rcu_spawn_one_nocb_kthread(rsp, cpu);
}

/*
--
1.9.1


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