* [PATCH -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice
@ 2019-01-24 18:07 Cyrill Gorcunov
2019-01-24 18:14 ` [PATCH v2 " Cyrill Gorcunov
0 siblings, 1 reply; 3+ messages in thread
From: Cyrill Gorcunov @ 2019-01-24 18:07 UTC (permalink / raw)
To: LKML; +Cc: Paul E. McKenney
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@linux.ibm.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
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]
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v2 -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice
2019-01-24 18:07 [PATCH -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice Cyrill Gorcunov
@ 2019-01-24 18:14 ` Cyrill Gorcunov
2019-01-24 20:59 ` Paul E. McKenney
0 siblings, 1 reply; 3+ messages in thread
From: Cyrill Gorcunov @ 2019-01-24 18:14 UTC (permalink / raw)
To: LKML; +Cc: Paul E. McKenney
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@linux.ibm.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
The prev patch body has been screwed, sorry.
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);
}
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2 -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice
2019-01-24 18:14 ` [PATCH v2 " Cyrill Gorcunov
@ 2019-01-24 20:59 ` Paul E. McKenney
0 siblings, 0 replies; 3+ messages in thread
From: Paul E. McKenney @ 2019-01-24 20:59 UTC (permalink / raw)
To: Cyrill Gorcunov; +Cc: LKML
On Thu, Jan 24, 2019 at 09:14:37PM +0300, Cyrill Gorcunov wrote:
> 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@linux.ibm.com>
> Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Good eyes, good combo optimization of both space and time, thank you!!!
Queued, most likely for v5.2.
Thanx, Paul
> ---
> The prev patch body has been screwed, sorry.
>
> 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);
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-01-24 18:07 [PATCH -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice Cyrill Gorcunov
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2019-01-24 20:59 ` Paul E. McKenney
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