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SubjectRe: [PATCH 17/21] cpuidle: avoid unnecessary kzalloc/free of struct cpuidle_driver_kobj
On 09/22/2013 03:21 AM, Viresh Kumar wrote:
> For CONFIG_CPU_IDLE_MULTIPLE_DRIVERS, struct cpuidle_device always needs to
> allocate struct cpuidle_driver_kobj for all CPUs and so there is no real need to
> have a pointer to it inside struct cpuidle_device.
>
> This patch makes a object instance of struct cpuidle_driver_kobj inside struct
> cpuidle_device instead of a pointer.
>
> It also makes kobj_driver dependent on CONFIG_CPU_IDLE_MULTIPLE_DRIVERS.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Comment similar to patch 16/21. If you try to offline/online a cpu, that
should lead to a kernel warning.

> ---
> drivers/cpuidle/sysfs.c | 20 +++-----------------
> include/linux/cpuidle.h | 11 +++++++++--
> 2 files changed, 12 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
> index db0aac3..3386d64 100644
> --- a/drivers/cpuidle/sysfs.c
> +++ b/drivers/cpuidle/sysfs.c
> @@ -439,12 +439,6 @@ static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
> static struct cpuidle_driver_attr attr_driver_##_name = \
> __ATTR(_name, 0644, show, NULL)
>
> -struct cpuidle_driver_kobj {
> - struct cpuidle_driver *drv;
> - struct completion kobj_unregister;
> - struct kobject kobj;
> -};
> -
> struct cpuidle_driver_attr {
> struct attribute attr;
> ssize_t (*show)(struct cpuidle_driver *, char *);
> @@ -518,27 +512,20 @@ static struct kobj_type ktype_driver_cpuidle = {
> */
> static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
> {
> - struct cpuidle_driver_kobj *kdrv;
> + struct cpuidle_driver_kobj *kdrv = &dev->kobj_driver;
> struct cpuidle_device_kobj *kdev = &dev->kobj_dev;
> struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
> int ret;
>
> - kdrv = kzalloc(sizeof(*kdrv), GFP_KERNEL);
> - if (!kdrv)
> - return -ENOMEM;
> -
> kdrv->drv = drv;
> init_completion(&kdrv->kobj_unregister);
>
> ret = kobject_init_and_add(&kdrv->kobj, &ktype_driver_cpuidle,
> &kdev->kobj, "driver");
> - if (ret) {
> - kfree(kdrv);
> + if (ret)
> return ret;
> - }
>
> kobject_uevent(&kdrv->kobj, KOBJ_ADD);
> - dev->kobj_driver = kdrv;
>
> return ret;
> }
> @@ -549,10 +536,9 @@ static int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
> */
> static void cpuidle_remove_driver_sysfs(struct cpuidle_device *dev)
> {
> - struct cpuidle_driver_kobj *kdrv = dev->kobj_driver;
> + struct cpuidle_driver_kobj *kdrv = &dev->kobj_driver;
> kobject_put(&kdrv->kobj);
> wait_for_completion(&kdrv->kobj_unregister);
> - kfree(kdrv);
> }
> #else
> static inline int cpuidle_add_driver_sysfs(struct cpuidle_device *dev)
> diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
> index 1fc5cb5..0f0da17 100644
> --- a/include/linux/cpuidle.h
> +++ b/include/linux/cpuidle.h
> @@ -62,7 +62,6 @@ struct cpuidle_state {
> #define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
>
> struct cpuidle_state_kobj;
> -struct cpuidle_driver_kobj;
>
> struct cpuidle_device_kobj {
> struct cpuidle_device *dev;
> @@ -70,6 +69,12 @@ struct cpuidle_device_kobj {
> struct kobject kobj;
> };
>
> +struct cpuidle_driver_kobj {
> + struct cpuidle_driver *drv;
> + struct completion kobj_unregister;
> + struct kobject kobj;
> +};
> +
> struct cpuidle_device {
> unsigned int registered:1;
> unsigned int enabled:1;
> @@ -79,7 +84,9 @@ struct cpuidle_device {
> int state_count;
> struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
> struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
> - struct cpuidle_driver_kobj *kobj_driver;
> +#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
> + struct cpuidle_driver_kobj kobj_driver;
> +#endif
> struct cpuidle_device_kobj kobj_dev;
> struct list_head device_list;
>
>


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