On Monday, February 11, 2013 01:20:00 PM Viresh Kumar wrote:
> Currently, there can't be multiple instances of single governor_type. If we
> have
> a multi-package system, where we have multiple instances of struct policy (per
> package), we can't have multiple instances of same governor. i.e. We can't
> have
> multiple instances of ondemand governor for multiple packages.
>
> Governors directory in sysfs is created at /sys/devices/system/cpu/cpufreq/
> governor-name/. Which again reflects that there can be only one instance of a
> governor_type in the system.
>
> This is a bottleneck for multicluster system, where we want different packages
> to use same governor type, but with different tunables.
>
> This patch is inclined towards providing this infrastructure. Because we are
> required to allocate governor's resources dynamically now, we must do it at
> policy creation and end. And so got CPUFREQ_GOV_POLICY_INIT/EXIT.
Are those new events NOPs now?
> Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
> ---
> drivers/cpufreq/cpufreq.c | 21 ++++++++++++++++++---
> include/linux/cpufreq.h | 9 ++++++---
> 2 files changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 04aab05..40f7083 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1081,6 +1081,8 @@ static int __cpufreq_remove_dev(struct device *dev,
> struct subsys_interface *sif
>
> /* If cpu is last user of policy, free policy */
> if (cpus == 1) {
> + __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
> +
> lock_policy_rwsem_read(cpu);
> kobj = &data->kobj;
> cmp = &data->kobj_unregister;
> @@ -1669,7 +1671,7 @@ EXPORT_SYMBOL(cpufreq_get_policy);
> static int __cpufreq_set_policy(struct cpufreq_policy *data,
> struct cpufreq_policy *policy)
> {
> - int ret = 0;
> + int ret = 0, failed = 1;
> struct cpufreq_driver *driver = rcu_dereference(cpufreq_driver);
>
> pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
> @@ -1724,18 +1726,31 @@ static int __cpufreq_set_policy(struct cpufreq_policy
> *data,
> pr_debug("governor switch\n");
>
> /* end old governor */
> - if (data->governor)
> + if (data->governor) {
> __cpufreq_governor(data, CPUFREQ_GOV_STOP);
> + __cpufreq_governor(data,
> + CPUFREQ_GOV_POLICY_EXIT);
> + }
>
> /* start new governor */
> data->governor = policy->governor;
> - if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
> + if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT))
> {
> + if (!__cpufreq_governor(data,
> CPUFREQ_GOV_START))
> + failed = 0;
> + else
> + __cpufreq_governor(data,
> +
> CPUFREQ_GOV_POLICY_EXIT);
> + }
> +
> + if (failed) {
> /* new governor failed, so re-start old one */
> pr_debug("starting governor %s failed\n",
> data->governor->name);
> if (old_gov) {
> data->governor = old_gov;
> __cpufreq_governor(data,
> +
> CPUFREQ_GOV_POLICY_INIT);
> + __cpufreq_governor(data,
> CPUFREQ_GOV_START);
> }
> ret = -EINVAL;
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index a22944c..3b822ce 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -106,6 +106,7 @@ struct cpufreq_policy {
> * governors are used */
> unsigned int policy; /* see above */
> struct cpufreq_governor *governor; /* see below */
> + void *governor_data;
>
> struct work_struct update; /* if update_policy() needs to be
> * called, but you're in IRQ context */
> @@ -178,9 +179,11 @@ static inline unsigned long cpufreq_scale(unsigned long
> old, u_int div, u_int mu
> * CPUFREQ GOVERNORS *
> *********************************************************************/
>
> -#define CPUFREQ_GOV_START 1
> -#define CPUFREQ_GOV_STOP 2
> -#define CPUFREQ_GOV_LIMITS 3
> +#define CPUFREQ_GOV_START 1
> +#define CPUFREQ_GOV_STOP 2
> +#define CPUFREQ_GOV_LIMITS 3
> +#define CPUFREQ_GOV_POLICY_INIT 4
> +#define CPUFREQ_GOV_POLICY_EXIT 4
Why don't you use different values here?
If you need only one value, one #define should be sufficient.
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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