From d08d1b27fe2a7f6923952613f5fab56ae47a6f5b Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 22 Feb 2017 13:58:52 +0530 Subject: PM / QoS: Remove global notifiers They were never used in the kernel, so get rid of them. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/base/power/qos.c | 50 ++++-------------------------------------------- 1 file changed, 4 insertions(+), 46 deletions(-) (limited to 'drivers/base/power/qos.c') diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index d888d9869b6a..271bec73185e 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -17,12 +17,9 @@ * * This QoS design is best effort based. Dependents register their QoS needs. * Watchers register to keep track of the current QoS needs of the system. - * Watchers can register different types of notification callbacks: - * . a per-device notification callback using the dev_pm_qos_*_notifier API. - * The notification chain data is stored in the per-device constraint - * data struct. - * . a system-wide notification callback using the dev_pm_qos_*_global_notifier - * API. The notification chain data is stored in a static variable. + * Watchers can register a per-device notification callback using the + * dev_pm_qos_*_notifier API. The notification chain data is stored in the + * per-device constraint data struct. * * Note about the per-device constraint data struct allocation: * . The per-device constraints data struct ptr is tored into the device @@ -49,8 +46,6 @@ static DEFINE_MUTEX(dev_pm_qos_mtx); static DEFINE_MUTEX(dev_pm_qos_sysfs_mtx); -static BLOCKING_NOTIFIER_HEAD(dev_pm_notifiers); - /** * __dev_pm_qos_flags - Check PM QoS flags for a given device. * @dev: Device to check the PM QoS flags for. @@ -135,8 +130,7 @@ s32 dev_pm_qos_read_value(struct device *dev) * @value: Value to assign to the QoS request. * * Internal function to update the constraints list using the PM QoS core - * code and if needed call the per-device and the global notification - * callbacks + * code and if needed call the per-device callbacks. */ static int apply_constraint(struct dev_pm_qos_request *req, enum pm_qos_req_action action, s32 value) @@ -148,12 +142,6 @@ static int apply_constraint(struct dev_pm_qos_request *req, case DEV_PM_QOS_RESUME_LATENCY: ret = pm_qos_update_target(&qos->resume_latency, &req->data.pnode, action, value); - if (ret) { - value = pm_qos_read_value(&qos->resume_latency); - blocking_notifier_call_chain(&dev_pm_notifiers, - (unsigned long)value, - req); - } break; case DEV_PM_QOS_LATENCY_TOLERANCE: ret = pm_qos_update_target(&qos->latency_tolerance, @@ -535,36 +523,6 @@ int dev_pm_qos_remove_notifier(struct device *dev, } EXPORT_SYMBOL_GPL(dev_pm_qos_remove_notifier); -/** - * dev_pm_qos_add_global_notifier - sets notification entry for changes to - * target value of the PM QoS constraints for any device - * - * @notifier: notifier block managed by caller. - * - * Will register the notifier into a notification chain that gets called - * upon changes to the target value for any device. - */ -int dev_pm_qos_add_global_notifier(struct notifier_block *notifier) -{ - return blocking_notifier_chain_register(&dev_pm_notifiers, notifier); -} -EXPORT_SYMBOL_GPL(dev_pm_qos_add_global_notifier); - -/** - * dev_pm_qos_remove_global_notifier - deletes notification for changes to - * target value of PM QoS constraints for any device - * - * @notifier: notifier block to be removed. - * - * Will remove the notifier from the notification chain that gets called - * upon changes to the target value for any device. - */ -int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier) -{ - return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier); -} -EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier); - /** * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor. * @dev: Device whose ancestor to add the request for. -- cgit From 6dbf5cea05a7098a69f294c96b6d76f08562cae5 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 24 Feb 2017 13:25:14 +0100 Subject: cpuidle: menu: Avoid taking spinlock for accessing QoS values After commit 9908859acaa9 (cpuidle/menu: add per CPU PM QoS resume latency consideration) the cpuidle menu governor calls dev_pm_qos_read_value() on CPU devices to read the current resume latency QoS constraint values for them. That function takes a spinlock to prevent the device's power.qos pointer from becoming NULL during the access which is a problem for the RT patchset where spinlocks are converted into mutexes and the idle loop stops working. However, it is not even necessary for the menu governor to take that spinlock, because the power.qos pointer accessed under it cannot be modified during the access anyway. For this reason, introduce a "raw" routine for accessing device QoS resume latency constraints without locking and use it in the menu governor. Fixes: 9908859acaa9 (cpuidle/menu: add per CPU PM QoS resume latency consideration) Acked-by: Alex Shi Signed-off-by: Rafael J. Wysocki --- drivers/base/power/qos.c | 3 +-- drivers/cpuidle/governors/menu.c | 2 +- include/linux/pm_qos.h | 7 +++++++ 3 files changed, 9 insertions(+), 3 deletions(-) (limited to 'drivers/base/power/qos.c') diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index 58fcc758334e..73142d086240 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -108,8 +108,7 @@ s32 __dev_pm_qos_read_value(struct device *dev) { lockdep_assert_held(&dev->power.lock); - return IS_ERR_OR_NULL(dev->power.qos) ? - 0 : pm_qos_read_value(&dev->power.qos->resume_latency); + return dev_pm_qos_raw_read_value(dev); } /** diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 8d6d25c38c02..6d6f46e79d94 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -287,7 +287,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) unsigned int interactivity_req; unsigned int expected_interval; unsigned long nr_iowaiters, cpu_load; - int resume_latency = dev_pm_qos_read_value(device); + int resume_latency = dev_pm_qos_raw_read_value(device); if (data->needs_update) { menu_update(drv, dev); diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h index 0f65d36c2a75..5aba9f47899d 100644 --- a/include/linux/pm_qos.h +++ b/include/linux/pm_qos.h @@ -173,6 +173,12 @@ static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return dev->power.qos->flags_req->data.flr.flags; } + +static inline s32 dev_pm_qos_raw_read_value(struct device *dev) +{ + return IS_ERR_OR_NULL(dev->power.qos) ? + 0 : pm_qos_read_value(&dev->power.qos->resume_latency); +} #else static inline enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask) @@ -237,6 +243,7 @@ static inline void dev_pm_qos_hide_latency_tolerance(struct device *dev) {} static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev) { return 0; } static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return 0; } +static inline s32 dev_pm_qos_raw_read_value(struct device *dev) { return 0; } #endif #endif -- cgit