Re: [PATCH V2] Cpufreq: Make governor data on nonboot cpus across system suspend/resume

Rafael J. Wysocki
2013-11-21T14:43:59Z

On Saturday, November 16, 2013 11:36:24 PM Lan Tianyu wrote:
> Currently, governor of nonboot cpus will be put to EXIT when system suspend.
> Since all these cpus will be unplugged and the governor usage_count decreases
> to zero. The governor data and its sysfs interfaces will be freed or released.
> This makes user config of these governors loss during suspend and resume.
>
> This doesn't happen on the governor covering boot cpu because it isn't
> unplugged during system suspend.
>
> To fix this issue, skipping governor exit during system suspend and check
> policy governor data to determine whether the governor is really needed
> to be initialized when do init. If not, return EALREADY to indicate the
> governor has been initialized and should do nothing. __cpufreq_governor()
> convert EALREADY to 0 as return value for INIT event since governor is
> still under INIT state and can do START operation.
>
> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
> ---
> Change since v1:
> Change coding style.
>
> drivers/cpufreq/cpufreq.c | 10 +++++++---
> drivers/cpufreq/cpufreq_governor.c | 13 ++++++++++++-
> 2 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 02d534d..73ad593 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1239,7 +1239,7 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
>
> /* If cpu is last user of policy, free policy */
> if (cpus == 1) {
> - if (has_target()) {
> + if (has_target() && !frozen) {
> ret = __cpufreq_governor(policy,
> CPUFREQ_GOV_POLICY_EXIT);
> if (ret) {
> @@ -1818,9 +1818,13 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
> mutex_unlock(&cpufreq_governor_lock);
> }
>
> - if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||

The inner parens are not necessary.

> - ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret))
> + if ((event == CPUFREQ_GOV_POLICY_INIT) && ret) {

Same here.

> + module_put(policy->governor->owner);
> + if (ret == -EALREADY)
> + return 0;
> + } else if ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret) {

Same here.

> module_put(policy->governor->owner);
> + }

Can you please combine these checks with the checks made right after
calling policy->governor->governor() as indicated by Viresh?

Rafael