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Subject[RFC v2 2/5] rcu: Use for_each_leaf_node_cpu() in RCU stall checking
Date
Use for_each_leaf_node_cpu() in RCU stall checking code, to save some
extra checks, based on the fact that ->qsmask is mostly more sparse than
cpu_possible_mask.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
kernel/rcu/tree.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b56e2dc31ba5..4e5b81c843de 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1417,10 +1417,11 @@ static void rcu_dump_cpu_stacks(struct rcu_state *rsp)

rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
- for_each_leaf_node_possible_cpu(rnp, cpu)
- if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu))
- if (!trigger_single_cpu_backtrace(cpu))
- dump_cpu_task(cpu);
+
+ for_each_leaf_node_cpu(rnp, rnp->qsmask, cpu)
+ if (!trigger_single_cpu_backtrace(cpu))
+ dump_cpu_task(cpu);
+
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
}
@@ -1490,13 +1491,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags);
ndetected += rcu_print_task_stall(rnp);
- if (rnp->qsmask != 0) {
- for_each_leaf_node_possible_cpu(rnp, cpu)
- if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) {
- print_cpu_stall_info(rsp, cpu);
- ndetected++;
- }
+
+ for_each_leaf_node_cpu(rnp, rnp->qsmask, cpu) {
+ print_cpu_stall_info(rsp, cpu);
+ ndetected++;
}
+
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}

--
2.10.2
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