| Message ID | 1458796269-6158-3-git-send-email-jszhang@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <jszhang@marvell.com> > --- > 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.
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); } /** @@ -144,7 +140,7 @@ int __init arm_cpuidle_init(int cpu) ret = arm_cpuidle_read_ops(cpu_node, cpu); if (!ret) { - if (cpuidle_ops[cpu].init) + if (cpuidle_ops[cpu].init && cpuidle_ops[cpu].suspend) ret = cpuidle_ops[cpu].init(cpu_node, cpu); else ret = -EOPNOTSUPP;
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 <jszhang@marvell.com> --- arch/arm/kernel/cpuidle.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)