From ed77134bfccf5e75b6cbadab268e559dbe6a4ebb Mon Sep 17 00:00:00 2001 From: Mark Gross Date: Thu, 6 May 2010 01:59:26 +0200 Subject: PM QOS update This patch changes the string based list management to a handle base implementation to help with the hot path use of pm-qos, it also renames much of the API to use "request" as opposed to "requirement" that was used in the initial implementation. I did this because request more accurately represents what it actually does. Also, I added a string based ABI for users wanting to use a string interface. So if the user writes 0xDDDDDDDD formatted hex it will be accepted by the interface. (someone asked me for it and I don't think it hurts anything.) This patch updates some documentation input I got from Randy. Signed-off-by: markgross Signed-off-by: Rafael J. Wysocki --- kernel/pm_qos_params.c | 214 ++++++++++++++++++++++++------------------------- 1 file changed, 103 insertions(+), 111 deletions(-) (limited to 'kernel') diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c index 3db49b9ca374..a1aea040eb57 100644 --- a/kernel/pm_qos_params.c +++ b/kernel/pm_qos_params.c @@ -2,7 +2,7 @@ * This module exposes the interface to kernel space for specifying * QoS dependencies. It provides infrastructure for registration of: * - * Dependents on a QoS value : register requirements + * Dependents on a QoS value : register requests * Watchers of QoS value : get notified when target QoS value changes * * This QoS design is best effort based. Dependents register their QoS needs. @@ -14,19 +14,21 @@ * timeout: usec <-- currently not used. * throughput: kbs (kilo byte / sec) * - * There are lists of pm_qos_objects each one wrapping requirements, notifiers + * There are lists of pm_qos_objects each one wrapping requests, notifiers * - * User mode requirements on a QOS parameter register themselves to the + * User mode requests on a QOS parameter register themselves to the * subsystem by opening the device node /dev/... and writing there request to * the node. As long as the process holds a file handle open to the node the * client continues to be accounted for. Upon file release the usermode - * requirement is removed and a new qos target is computed. This way when the - * requirement that the application has is cleaned up when closes the file + * request is removed and a new qos target is computed. This way when the + * request that the application has is cleaned up when closes the file * pointer or exits the pm_qos_object will get an opportunity to clean up. * * Mark Gross */ +/*#define DEBUG*/ + #include #include #include @@ -42,25 +44,25 @@ #include /* - * locking rule: all changes to requirements or notifiers lists + * locking rule: all changes to requests or notifiers lists * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock * held, taken with _irqsave. One lock to rule them all */ -struct requirement_list { +struct pm_qos_request_list { struct list_head list; union { s32 value; s32 usec; s32 kbps; }; - char *name; + int pm_qos_class; }; static s32 max_compare(s32 v1, s32 v2); static s32 min_compare(s32 v1, s32 v2); struct pm_qos_object { - struct requirement_list requirements; + struct pm_qos_request_list requests; struct blocking_notifier_head *notifiers; struct miscdevice pm_qos_power_miscdev; char *name; @@ -72,7 +74,7 @@ struct pm_qos_object { static struct pm_qos_object null_pm_qos; static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier); static struct pm_qos_object cpu_dma_pm_qos = { - .requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)}, + .requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)}, .notifiers = &cpu_dma_lat_notifier, .name = "cpu_dma_latency", .default_value = 2000 * USEC_PER_SEC, @@ -82,7 +84,7 @@ static struct pm_qos_object cpu_dma_pm_qos = { static BLOCKING_NOTIFIER_HEAD(network_lat_notifier); static struct pm_qos_object network_lat_pm_qos = { - .requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)}, + .requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)}, .notifiers = &network_lat_notifier, .name = "network_latency", .default_value = 2000 * USEC_PER_SEC, @@ -93,8 +95,7 @@ static struct pm_qos_object network_lat_pm_qos = { static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier); static struct pm_qos_object network_throughput_pm_qos = { - .requirements = - {LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)}, + .requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)}, .notifiers = &network_throughput_notifier, .name = "network_throughput", .default_value = 0, @@ -135,31 +136,34 @@ static s32 min_compare(s32 v1, s32 v2) } -static void update_target(int target) +static void update_target(int pm_qos_class) { s32 extreme_value; - struct requirement_list *node; + struct pm_qos_request_list *node; unsigned long flags; int call_notifier = 0; spin_lock_irqsave(&pm_qos_lock, flags); - extreme_value = pm_qos_array[target]->default_value; + extreme_value = pm_qos_array[pm_qos_class]->default_value; list_for_each_entry(node, - &pm_qos_array[target]->requirements.list, list) { - extreme_value = pm_qos_array[target]->comparitor( + &pm_qos_array[pm_qos_class]->requests.list, list) { + extreme_value = pm_qos_array[pm_qos_class]->comparitor( extreme_value, node->value); } - if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) { + if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) != + extreme_value) { call_notifier = 1; - atomic_set(&pm_qos_array[target]->target_value, extreme_value); - pr_debug(KERN_ERR "new target for qos %d is %d\n", target, - atomic_read(&pm_qos_array[target]->target_value)); + atomic_set(&pm_qos_array[pm_qos_class]->target_value, + extreme_value); + pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class, + atomic_read(&pm_qos_array[pm_qos_class]->target_value)); } spin_unlock_irqrestore(&pm_qos_lock, flags); if (call_notifier) - blocking_notifier_call_chain(pm_qos_array[target]->notifiers, - (unsigned long) extreme_value, NULL); + blocking_notifier_call_chain( + pm_qos_array[pm_qos_class]->notifiers, + (unsigned long) extreme_value, NULL); } static int register_pm_qos_misc(struct pm_qos_object *qos) @@ -185,125 +189,110 @@ static int find_pm_qos_object_by_minor(int minor) } /** - * pm_qos_requirement - returns current system wide qos expectation + * pm_qos_request - returns current system wide qos expectation * @pm_qos_class: identification of which qos value is requested * * This function returns the current target value in an atomic manner. */ -int pm_qos_requirement(int pm_qos_class) +int pm_qos_request(int pm_qos_class) { return atomic_read(&pm_qos_array[pm_qos_class]->target_value); } -EXPORT_SYMBOL_GPL(pm_qos_requirement); +EXPORT_SYMBOL_GPL(pm_qos_request); /** - * pm_qos_add_requirement - inserts new qos request into the list + * pm_qos_add_request - inserts new qos request into the list * @pm_qos_class: identifies which list of qos request to us - * @name: identifies the request * @value: defines the qos request * * This function inserts a new entry in the pm_qos_class list of requested qos * performance characteristics. It recomputes the aggregate QoS expectations - * for the pm_qos_class of parameters. + * for the pm_qos_class of parameters, and returns the pm_qos_request list + * element as a handle for use in updating and removal. Call needs to save + * this handle for later use. */ -int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value) +struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value) { - struct requirement_list *dep; + struct pm_qos_request_list *dep; unsigned long flags; - dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL); + dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL); if (dep) { if (value == PM_QOS_DEFAULT_VALUE) dep->value = pm_qos_array[pm_qos_class]->default_value; else dep->value = value; - dep->name = kstrdup(name, GFP_KERNEL); - if (!dep->name) - goto cleanup; + dep->pm_qos_class = pm_qos_class; spin_lock_irqsave(&pm_qos_lock, flags); list_add(&dep->list, - &pm_qos_array[pm_qos_class]->requirements.list); + &pm_qos_array[pm_qos_class]->requests.list); spin_unlock_irqrestore(&pm_qos_lock, flags); update_target(pm_qos_class); - - return 0; } -cleanup: - kfree(dep); - return -ENOMEM; + return dep; } -EXPORT_SYMBOL_GPL(pm_qos_add_requirement); +EXPORT_SYMBOL_GPL(pm_qos_add_request); /** - * pm_qos_update_requirement - modifies an existing qos request - * @pm_qos_class: identifies which list of qos request to us - * @name: identifies the request + * pm_qos_update_request - modifies an existing qos request + * @pm_qos_req : handle to list element holding a pm_qos request to use * @value: defines the qos request * - * Updates an existing qos requirement for the pm_qos_class of parameters along + * Updates an existing qos request for the pm_qos_class of parameters along * with updating the target pm_qos_class value. * - * If the named request isn't in the list then no change is made. + * Attempts are made to make this code callable on hot code paths. */ -int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value) +void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req, + s32 new_value) { unsigned long flags; - struct requirement_list *node; int pending_update = 0; + s32 temp; spin_lock_irqsave(&pm_qos_lock, flags); - list_for_each_entry(node, - &pm_qos_array[pm_qos_class]->requirements.list, list) { - if (strcmp(node->name, name) == 0) { - if (new_value == PM_QOS_DEFAULT_VALUE) - node->value = - pm_qos_array[pm_qos_class]->default_value; - else - node->value = new_value; - pending_update = 1; - break; - } + if (new_value == PM_QOS_DEFAULT_VALUE) + temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value; + else + temp = new_value; + + if (temp != pm_qos_req->value) { + pending_update = 1; + pm_qos_req->value = temp; } spin_unlock_irqrestore(&pm_qos_lock, flags); if (pending_update) - update_target(pm_qos_class); - - return 0; + update_target(pm_qos_req->pm_qos_class); } -EXPORT_SYMBOL_GPL(pm_qos_update_requirement); +EXPORT_SYMBOL_GPL(pm_qos_update_request); /** - * pm_qos_remove_requirement - modifies an existing qos request - * @pm_qos_class: identifies which list of qos request to us - * @name: identifies the request + * pm_qos_remove_request - modifies an existing qos request + * @pm_qos_req: handle to request list element * - * Will remove named qos request from pm_qos_class list of parameters and - * recompute the current target value for the pm_qos_class. + * Will remove pm qos request from the list of requests and + * recompute the current target value for the pm_qos_class. Call this + * on slow code paths. */ -void pm_qos_remove_requirement(int pm_qos_class, char *name) +void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req) { unsigned long flags; - struct requirement_list *node; - int pending_update = 0; + int qos_class; + + if (pm_qos_req == NULL) + return; + /* silent return to keep pcm code cleaner */ + qos_class = pm_qos_req->pm_qos_class; spin_lock_irqsave(&pm_qos_lock, flags); - list_for_each_entry(node, - &pm_qos_array[pm_qos_class]->requirements.list, list) { - if (strcmp(node->name, name) == 0) { - kfree(node->name); - list_del(&node->list); - kfree(node); - pending_update = 1; - break; - } - } + list_del(&pm_qos_req->list); + kfree(pm_qos_req); spin_unlock_irqrestore(&pm_qos_lock, flags); - if (pending_update) - update_target(pm_qos_class); + update_target(qos_class); } -EXPORT_SYMBOL_GPL(pm_qos_remove_requirement); +EXPORT_SYMBOL_GPL(pm_qos_remove_request); /** * pm_qos_add_notifier - sets notification entry for changes to target value @@ -313,7 +302,7 @@ EXPORT_SYMBOL_GPL(pm_qos_remove_requirement); * will register the notifier into a notification chain that gets called * upon changes to the pm_qos_class target value. */ - int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) +int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier) { int retval; @@ -343,21 +332,16 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) } EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); -#define PID_NAME_LEN 32 - static int pm_qos_power_open(struct inode *inode, struct file *filp) { - int ret; long pm_qos_class; - char name[PID_NAME_LEN]; pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); if (pm_qos_class >= 0) { - filp->private_data = (void *)pm_qos_class; - snprintf(name, PID_NAME_LEN, "process_%d", current->pid); - ret = pm_qos_add_requirement(pm_qos_class, name, - PM_QOS_DEFAULT_VALUE); - if (ret >= 0) + filp->private_data = (void *) pm_qos_add_request(pm_qos_class, + PM_QOS_DEFAULT_VALUE); + + if (filp->private_data) return 0; } return -EPERM; @@ -365,32 +349,40 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp) static int pm_qos_power_release(struct inode *inode, struct file *filp) { - int pm_qos_class; - char name[PID_NAME_LEN]; + struct pm_qos_request_list *req; - pm_qos_class = (long)filp->private_data; - snprintf(name, PID_NAME_LEN, "process_%d", current->pid); - pm_qos_remove_requirement(pm_qos_class, name); + req = (struct pm_qos_request_list *)filp->private_data; + pm_qos_remove_request(req); return 0; } + static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { s32 value; - int pm_qos_class; - char name[PID_NAME_LEN]; - - pm_qos_class = (long)filp->private_data; - if (count != sizeof(s32)) + int x; + char ascii_value[11]; + struct pm_qos_request_list *pm_qos_req; + + if (count == sizeof(s32)) { + if (copy_from_user(&value, buf, sizeof(s32))) + return -EFAULT; + } else if (count == 11) { /* len('0x12345678/0') */ + if (copy_from_user(ascii_value, buf, 11)) + return -EFAULT; + x = sscanf(ascii_value, "%x", &value); + if (x != 1) + return -EINVAL; + pr_debug(KERN_ERR "%s, %d, 0x%x\n", ascii_value, x, value); + } else return -EINVAL; - if (copy_from_user(&value, buf, sizeof(s32))) - return -EFAULT; - snprintf(name, PID_NAME_LEN, "process_%d", current->pid); - pm_qos_update_requirement(pm_qos_class, name, value); - return sizeof(s32); + pm_qos_req = (struct pm_qos_request_list *)filp->private_data; + pm_qos_update_request(pm_qos_req, value); + + return count; } -- cgit v1.2.1