* [PATCH] sofirq: make rcu_irq_enter()/rcu_irq_exit() called in pairs
@ 2009-10-27 8:00 Lai Jiangshan
2009-10-27 14:30 ` Paul E. McKenney
0 siblings, 1 reply; 2+ messages in thread
From: Lai Jiangshan @ 2009-10-27 8:00 UTC (permalink / raw)
To: Paul E. McKenney, Ingo Molnar, Thomas Gleixner, LKML
irq_enter() calls rcu_irq_enter() unconditionally,
the same as irq_exit() calls rcu_irq_exit().
It does not change the binary because rcu_irq_enter()
is dummy when !CONFIG_NO_HZ.
It's just a cleanup.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/kernel/softirq.c b/kernel/softirq.c
index f8749e5..21939d9 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -302,9 +302,9 @@ void irq_exit(void)
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
+ rcu_irq_exit();
#ifdef CONFIG_NO_HZ
/* Make sure that timer wheel updates are propagated */
- rcu_irq_exit();
if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())
tick_nohz_stop_sched_tick(0);
#endif
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] sofirq: make rcu_irq_enter()/rcu_irq_exit() called in pairs
2009-10-27 8:00 [PATCH] sofirq: make rcu_irq_enter()/rcu_irq_exit() called in pairs Lai Jiangshan
@ 2009-10-27 14:30 ` Paul E. McKenney
0 siblings, 0 replies; 2+ messages in thread
From: Paul E. McKenney @ 2009-10-27 14:30 UTC (permalink / raw)
To: Lai Jiangshan; +Cc: Ingo Molnar, Thomas Gleixner, LKML
On Tue, Oct 27, 2009 at 04:00:11PM +0800, Lai Jiangshan wrote:
>
> irq_enter() calls rcu_irq_enter() unconditionally,
> the same as irq_exit() calls rcu_irq_exit().
>
> It does not change the binary because rcu_irq_enter()
> is dummy when !CONFIG_NO_HZ.
>
> It's just a cleanup.
This does look like a nice cleanup! I will pull it in and test it.
Yes, it should be provably the same, but RCU has taught me to be quite
paranoid. ;-)
Thanx, Paul
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> ---
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index f8749e5..21939d9 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -302,9 +302,9 @@ void irq_exit(void)
> if (!in_interrupt() && local_softirq_pending())
> invoke_softirq();
>
> + rcu_irq_exit();
> #ifdef CONFIG_NO_HZ
> /* Make sure that timer wheel updates are propagated */
> - rcu_irq_exit();
> if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())
> tick_nohz_stop_sched_tick(0);
> #endif
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2009-10-27 8:00 [PATCH] sofirq: make rcu_irq_enter()/rcu_irq_exit() called in pairs Lai Jiangshan
2009-10-27 14:30 ` Paul E. McKenney
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