The recently introduced haltpoll driver is largely only useful with haltpoll governor. To allow drivers to associate with a particular idle behaviour, add a @governor property to 'struct cpuidle_driver' and thus allow a cpuidle driver to switch to a *preferred* governor on idle driver registration. We save the previous governor, and when an idle driver is unregistered we switch back to that.
The @governor can be overridden by cpuidle.governor= boot param or alternatively be ignored if the governor doesn't exist. Signed-off-by: Joao Martins <[email protected]> --- drivers/cpuidle/cpuidle.h | 1 + drivers/cpuidle/driver.c | 26 ++++++++++++++++++++++++++ drivers/cpuidle/governor.c | 6 +++--- include/linux/cpuidle.h | 3 +++ 4 files changed, 33 insertions(+), 3 deletions(-) diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h index d6613101af92..c046f49c1920 100644 --- a/drivers/cpuidle/cpuidle.h +++ b/drivers/cpuidle/cpuidle.h @@ -22,6 +22,7 @@ extern void cpuidle_install_idle_handler(void); extern void cpuidle_uninstall_idle_handler(void); /* governors */ +extern struct cpuidle_governor *cpuidle_find_governor(const char *str); extern int cpuidle_switch_governor(struct cpuidle_governor *gov); /* sysfs */ diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index dc32f34e68d9..16a3f6c5ad69 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -87,6 +87,7 @@ static inline int __cpuidle_set_driver(struct cpuidle_driver *drv) #else static struct cpuidle_driver *cpuidle_curr_driver; +static struct cpuidle_governor *cpuidle_prev_governor; /** * __cpuidle_get_cpu_driver - return the global cpuidle driver pointer. @@ -254,12 +255,25 @@ static void __cpuidle_unregister_driver(struct cpuidle_driver *drv) */ int cpuidle_register_driver(struct cpuidle_driver *drv) { + struct cpuidle_governor *gov; int ret; spin_lock(&cpuidle_driver_lock); ret = __cpuidle_register_driver(drv); spin_unlock(&cpuidle_driver_lock); + if (!ret && !strlen(param_governor) && drv->governor && + (cpuidle_get_driver() == drv)) { + mutex_lock(&cpuidle_lock); + gov = cpuidle_find_governor(drv->governor); + if (gov) { + cpuidle_prev_governor = cpuidle_curr_governor; + if (cpuidle_switch_governor(gov) < 0) + cpuidle_prev_governor = NULL; + } + mutex_unlock(&cpuidle_lock); + } + return ret; } EXPORT_SYMBOL_GPL(cpuidle_register_driver); @@ -274,9 +288,21 @@ EXPORT_SYMBOL_GPL(cpuidle_register_driver); */ void cpuidle_unregister_driver(struct cpuidle_driver *drv) { + bool enabled = (cpuidle_get_driver() == drv); + spin_lock(&cpuidle_driver_lock); __cpuidle_unregister_driver(drv); spin_unlock(&cpuidle_driver_lock); + + if (!enabled) + return; + + mutex_lock(&cpuidle_lock); + if (cpuidle_prev_governor) { + if (!cpuidle_switch_governor(cpuidle_prev_governor)) + cpuidle_prev_governor = NULL; + } + mutex_unlock(&cpuidle_lock); } EXPORT_SYMBOL_GPL(cpuidle_unregister_driver); diff --git a/drivers/cpuidle/governor.c b/drivers/cpuidle/governor.c index 2e3e14192bee..08707759469e 100644 --- a/drivers/cpuidle/governor.c +++ b/drivers/cpuidle/governor.c @@ -22,12 +22,12 @@ LIST_HEAD(cpuidle_governors); struct cpuidle_governor *cpuidle_curr_governor; /** - * __cpuidle_find_governor - finds a governor of the specified name + * cpuidle_find_governor - finds a governor of the specified name * @str: the name * * Must be called with cpuidle_lock acquired. */ -static struct cpuidle_governor * __cpuidle_find_governor(const char *str) +struct cpuidle_governor *cpuidle_find_governor(const char *str) { struct cpuidle_governor *gov; @@ -87,7 +87,7 @@ int cpuidle_register_governor(struct cpuidle_governor *gov) return -ENODEV; mutex_lock(&cpuidle_lock); - if (__cpuidle_find_governor(gov->name) == NULL) { + if (cpuidle_find_governor(gov->name) == NULL) { ret = 0; list_add_tail(&gov->governor_list, &cpuidle_governors); if (!cpuidle_curr_governor || diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 1a9f54eb3aa1..2dc4c6b19c25 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -121,6 +121,9 @@ struct cpuidle_driver { /* the driver handles the cpus in cpumask */ struct cpumask *cpumask; + + /* preferred governor to switch at register time */ + const char *governor; }; #ifdef CONFIG_CPU_IDLE -- 2.17.1
