From 0176005ec6aedf8d22074781028c7090924c64c3 Mon Sep 17 00:00:00 2001 From: Joao Martins Date: Sun, 8 Sep 2019 00:45:21 +0100 Subject: [PATCH 0776/2944] cpuidle: allow governor switch on cpuidle_register_driver() commit 11c59eae6633b8a7e77b8ee1cf908964d80c78cd upstream 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 Signed-off-by: Rafael J. Wysocki Signed-off-by: Yihao Wu Acked-by: Michael Wang --- drivers/cpuidle/cpuidle.h | 2 ++ drivers/cpuidle/driver.c | 25 +++++++++++++++++++++++++ drivers/cpuidle/governor.c | 7 ++++--- include/linux/cpuidle.h | 3 +++ 4 files changed, 34 insertions(+), 3 deletions(-) diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h index d661310..9f336af 100644 --- a/drivers/cpuidle/cpuidle.h +++ b/drivers/cpuidle/cpuidle.h @@ -9,6 +9,7 @@ /* For internal use only */ extern char param_governor[]; extern struct cpuidle_governor *cpuidle_curr_governor; +extern struct cpuidle_governor *cpuidle_prev_governor; extern struct list_head cpuidle_governors; extern struct list_head cpuidle_detected_devices; extern struct mutex cpuidle_lock; @@ -22,6 +23,7 @@ extern int cpuidle_enter_state(struct cpuidle_device *dev, 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 01acd88..9db1542 100644 --- a/drivers/cpuidle/driver.c +++ b/drivers/cpuidle/driver.c @@ -253,12 +253,25 @@ 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); @@ -273,9 +286,21 @@ int cpuidle_register_driver(struct cpuidle_driver *drv) */ 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 bb93e5c..1fcad4f 100644 --- a/drivers/cpuidle/governor.c +++ b/drivers/cpuidle/governor.c @@ -20,14 +20,15 @@ LIST_HEAD(cpuidle_governors); struct cpuidle_governor *cpuidle_curr_governor; +struct cpuidle_governor *cpuidle_prev_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 +88,7 @@ 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; if (!cpuidle_curr_governor || !strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) || diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 93081a5..7aea436 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -130,6 +130,9 @@ 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 -- 1.8.3.1