[PATCH -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice

From: Cyrill Gorcunov
Date: Thu Jan 24 2019 - 13:07:49 EST


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

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

Index: linux-next.git/kernel/rcu/tiny.c
===================================================================
--- linux-next.git.orig/kernel/rcu/tiny.c
+++ linux-next.git/kernel/rcu/tiny.c
@@ -65,7 +65,7 @@ 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);
}
Subject: [PATCH]