From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 -next] rcu: rcu_qs -- Use raise_softirq_irqoff to not save irqs twice
Date: Thu, 24 Jan 2019 12:59:27 -0800 [thread overview]
Message-ID: <20190124205927.GV4240@linux.ibm.com> (raw)
In-Reply-To: <20190124181437.GE2332@uranus.lan>
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);
> }
>
prev parent reply other threads:[~2019-01-24 20:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
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 ` [PATCH v2 " Cyrill Gorcunov
2019-01-24 20:59 ` Paul E. McKenney [this message]
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