[PATCH tip/core/rcu 13/14] rcu: Don't scan root rcu_node structure for stalled tasks

From: Paul E. McKenney
Date: Wed Jan 07 2015 - 12:34:59 EST


From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

Now that blocked tasks are no longer migrated to the root rcu_node
structure, there is no need to scan the root rcu_node structure for
blocked tasks stalling the current grace period. This commit therefore
removes this scan.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 9 ---------
1 file changed, 9 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 24d3c67f7be7..4ed2c2842103 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1107,15 +1107,6 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
raw_spin_unlock_irqrestore(&rnp->lock, flags);
}

- /*
- * Now rat on any tasks that got kicked up to the root rcu_node
- * due to CPU offlining.
- */
- rnp = rcu_get_root(rsp);
- raw_spin_lock_irqsave(&rnp->lock, flags);
- ndetected += rcu_print_task_stall(rnp);
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
-
print_cpu_stall_info_end();
for_each_possible_cpu(cpu)
totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen;
--
1.8.1.5

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