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ARM: 8586/1: cpuidle: make arm_cpuidle_suspend() a bit more efficient

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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_read_ops() to reduce arm_cpuidle_suspend
overhead a bit.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Jisheng Zhang 2016-07-14 11:39:18 +01:00 committed by Russell King
parent f222a76952
commit c3fbbf9308
1 changed files with 6 additions and 11 deletions
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17
arch/arm/kernel/cpuidle.c
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@ -47,18 +47,13 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
* This function calls the underlying arch specific low level PM code as
* registered at the init time.
*
* Returns -EOPNOTSUPP if no suspend callback is defined, the result of the
* callback otherwise.
* Returns the result of the suspend callback.
*/
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);
}
/**
@ -92,8 +87,8 @@ static const struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method)
* process.
*
* Return 0 on sucess, -ENOENT if no 'enable-method' is defined, -EOPNOTSUPP if
* no cpuidle_ops is registered for the 'enable-method', or if no init callback
* is defined.
* no cpuidle_ops is registered for the 'enable-method', or if either init or
* suspend callback isn't defined.
*/
static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu)
{
@ -111,8 +106,8 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu)
return -EOPNOTSUPP;
}
if (!ops->init) {
pr_warn("cpuidle_ops '%s': no init callback\n",
if (!ops->init || !ops->suspend) {
pr_warn("cpuidle_ops '%s': no init or suspend callback\n",
enable_method);
return -EOPNOTSUPP;
}