[PATCH tip/core/rcu 03/18] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice

From: Paul E. McKenney
Date: Tue Mar 26 2019 - 19:14:18 EST


From: Cyrill Gorcunov <gorcunov@xxxxxxxxx>

The rcu_qs is disabling IRQs by self so no need to do the same in raise_softirq
but instead we can save some cycles using raise_softirq_irqoff directly.

CC: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
kernel/rcu/tiny.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 911bd9076d43..477b4eb44af5 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -52,7 +52,7 @@ void rcu_qs(void)
local_irq_save(flags);
if (rcu_ctrlblk.donetail != rcu_ctrlblk.curtail) {
rcu_ctrlblk.donetail = rcu_ctrlblk.curtail;
- raise_softirq(RCU_SOFTIRQ);
+ raise_softirq_irqoff(RCU_SOFTIRQ);
}
local_irq_restore(flags);
}
--
2.17.1