From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Fri, 25 Mar 2016 12:52:45 +0100 Subject: [PATCH 2/2] ARM: cpuidle: make arm_cpuidle_suspend() a bit more efficient In-Reply-To: <1458796269-6158-3-git-send-email-jszhang@marvell.com> References: <1458796269-6158-1-git-send-email-jszhang@marvell.com> <1458796269-6158-3-git-send-email-jszhang@marvell.com> Message-ID: <56F5268D.70000@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/24/2016 06:11 AM, Jisheng Zhang wrote: > Currently, we check cpuidle_ops.suspend every time when entering a > low-power idle state. But this check could be avoided in this hot path > by moving it into arm_cpuidle_init() to reduce arm_cpuidle_suspend() > overhead a bit. > > Signed-off-by: Jisheng Zhang > --- > arch/arm/kernel/cpuidle.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c > index f108d8f..bf68d49 100644 > --- a/arch/arm/kernel/cpuidle.c > +++ b/arch/arm/kernel/cpuidle.c > @@ -52,13 +52,9 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev, > */ > int arm_cpuidle_suspend(int index) > { > - int ret = -EOPNOTSUPP; > int cpu = smp_processor_id(); > > - if (cpuidle_ops[cpu].suspend) > - ret = cpuidle_ops[cpu].suspend(index); > - > - return ret; > + return cpuidle_ops[cpu].suspend(index); > } I agree with the optimization but, same comment than the previous patch, it should be handled in arm_cpuidle_read_ops. -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog