From: James Bottomley Date: Mon, 19 Jul 2010 00:00:18 +0000 (+0200) Subject: pm_qos: Reimplement using plists X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5f279845f9d684661563894d44729a0c706375b4;p=linux-beck.git pm_qos: Reimplement using plists A lot of the pm_qos extremal value handling is really duplicating what a priority ordered list does, just in a less efficient fashion. Simply redoing the implementation in terms of a plist gets rid of a lot of this junk (although there are several other strange things that could do with tidying up, like pm_qos_request_list has to carry the pm_qos_class with every node, simply because it doesn't get passed in to pm_qos_update_request even though every caller knows full well what parameter it's updating). I think this redo is a win independent of android, so we should do something like this now. Signed-off-by: James Bottomley Signed-off-by: mark gross Signed-off-by: Rafael J. Wysocki --- diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c index f42d3f737a33..db8e51d7f392 100644 --- a/kernel/pm_qos_params.c +++ b/kernel/pm_qos_params.c @@ -30,6 +30,7 @@ /*#define DEBUG*/ #include +#include #include #include #include @@ -49,58 +50,53 @@ * held, taken with _irqsave. One lock to rule them all */ struct pm_qos_request_list { - struct list_head list; - union { - s32 value; - s32 usec; - s32 kbps; - }; + struct plist_node list; int pm_qos_class; }; -static s32 max_compare(s32 v1, s32 v2); -static s32 min_compare(s32 v1, s32 v2); +enum pm_qos_type { + PM_QOS_MAX, /* return the largest value */ + PM_QOS_MIN /* return the smallest value */ +}; struct pm_qos_object { - struct pm_qos_request_list requests; + struct plist_head requests; struct blocking_notifier_head *notifiers; struct miscdevice pm_qos_power_miscdev; char *name; s32 default_value; - atomic_t target_value; - s32 (*comparitor)(s32, s32); + enum pm_qos_type type; }; +static DEFINE_SPINLOCK(pm_qos_lock); + 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 = { - .requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)}, + .requests = PLIST_HEAD_INIT(cpu_dma_pm_qos.requests, pm_qos_lock), .notifiers = &cpu_dma_lat_notifier, .name = "cpu_dma_latency", .default_value = 2000 * USEC_PER_SEC, - .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC), - .comparitor = min_compare + .type = PM_QOS_MIN, }; static BLOCKING_NOTIFIER_HEAD(network_lat_notifier); static struct pm_qos_object network_lat_pm_qos = { - .requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)}, + .requests = PLIST_HEAD_INIT(network_lat_pm_qos.requests, pm_qos_lock), .notifiers = &network_lat_notifier, .name = "network_latency", .default_value = 2000 * USEC_PER_SEC, - .target_value = ATOMIC_INIT(2000 * USEC_PER_SEC), - .comparitor = min_compare + .type = PM_QOS_MIN }; static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier); static struct pm_qos_object network_throughput_pm_qos = { - .requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)}, + .requests = PLIST_HEAD_INIT(network_throughput_pm_qos.requests, pm_qos_lock), .notifiers = &network_throughput_notifier, .name = "network_throughput", .default_value = 0, - .target_value = ATOMIC_INIT(0), - .comparitor = max_compare + .type = PM_QOS_MAX, }; @@ -111,8 +107,6 @@ static struct pm_qos_object *pm_qos_array[] = { &network_throughput_pm_qos }; -static DEFINE_SPINLOCK(pm_qos_lock); - static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos); static int pm_qos_power_open(struct inode *inode, struct file *filp); @@ -124,46 +118,55 @@ static const struct file_operations pm_qos_power_fops = { .release = pm_qos_power_release, }; -/* static helper functions */ -static s32 max_compare(s32 v1, s32 v2) +/* unlocked internal variant */ +static inline int pm_qos_get_value(struct pm_qos_object *o) { - return max(v1, v2); -} + if (plist_head_empty(&o->requests)) + return o->default_value; -static s32 min_compare(s32 v1, s32 v2) -{ - return min(v1, v2); -} + switch (o->type) { + case PM_QOS_MIN: + return plist_last(&o->requests)->prio; + case PM_QOS_MAX: + return plist_first(&o->requests)->prio; -static void update_target(int pm_qos_class) + default: + /* runtime check for not using enum */ + BUG(); + } +} + +static void update_target(struct pm_qos_object *o, struct plist_node *node, + int del, int value) { - s32 extreme_value; - struct pm_qos_request_list *node; unsigned long flags; - int call_notifier = 0; + int prev_value, curr_value; spin_lock_irqsave(&pm_qos_lock, flags); - extreme_value = pm_qos_array[pm_qos_class]->default_value; - list_for_each_entry(node, - &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[pm_qos_class]->target_value) != - extreme_value) { - call_notifier = 1; - 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)); + prev_value = pm_qos_get_value(o); + /* PM_QOS_DEFAULT_VALUE is a signal that the value is unchanged */ + if (value != PM_QOS_DEFAULT_VALUE) { + /* + * to change the list, we atomically remove, reinit + * with new value and add, then see if the extremal + * changed + */ + plist_del(node, &o->requests); + plist_node_init(node, value); + plist_add(node, &o->requests); + } else if (del) { + plist_del(node, &o->requests); + } else { + plist_add(node, &o->requests); } + curr_value = pm_qos_get_value(o); spin_unlock_irqrestore(&pm_qos_lock, flags); - if (call_notifier) - blocking_notifier_call_chain( - pm_qos_array[pm_qos_class]->notifiers, - (unsigned long) extreme_value, NULL); + if (prev_value != curr_value) + blocking_notifier_call_chain(o->notifiers, + (unsigned long)curr_value, + NULL); } static int register_pm_qos_misc(struct pm_qos_object *qos) @@ -196,7 +199,14 @@ static int find_pm_qos_object_by_minor(int minor) */ int pm_qos_request(int pm_qos_class) { - return atomic_read(&pm_qos_array[pm_qos_class]->target_value); + unsigned long flags; + int value; + + spin_lock_irqsave(&pm_qos_lock, flags); + value = pm_qos_get_value(pm_qos_array[pm_qos_class]); + spin_unlock_irqrestore(&pm_qos_lock, flags); + + return value; } EXPORT_SYMBOL_GPL(pm_qos_request); @@ -214,21 +224,19 @@ EXPORT_SYMBOL_GPL(pm_qos_request); struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value) { struct pm_qos_request_list *dep; - unsigned long flags; dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL); if (dep) { + struct pm_qos_object *o = pm_qos_array[pm_qos_class]; + int new_value; + if (value == PM_QOS_DEFAULT_VALUE) - dep->value = pm_qos_array[pm_qos_class]->default_value; + new_value = o->default_value; else - dep->value = value; + new_value = value; + plist_node_init(&dep->list, new_value); dep->pm_qos_class = pm_qos_class; - - spin_lock_irqsave(&pm_qos_lock, flags); - list_add(&dep->list, - &pm_qos_array[pm_qos_class]->requests.list); - spin_unlock_irqrestore(&pm_qos_lock, flags); - update_target(pm_qos_class); + update_target(o, &dep->list, 0, PM_QOS_DEFAULT_VALUE); } return dep; @@ -246,27 +254,23 @@ EXPORT_SYMBOL_GPL(pm_qos_add_request); * Attempts are made to make this code callable on hot code paths. */ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req, - s32 new_value) + s32 new_value) { - unsigned long flags; - int pending_update = 0; s32 temp; + struct pm_qos_object *o; - if (pm_qos_req) { /*guard against callers passing in null */ - spin_lock_irqsave(&pm_qos_lock, flags); - 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_req->pm_qos_class); - } + if (!pm_qos_req) /*guard against callers passing in null */ + return; + + o = pm_qos_array[pm_qos_req->pm_qos_class]; + + if (new_value == PM_QOS_DEFAULT_VALUE) + temp = o->default_value; + else + temp = new_value; + + if (temp != pm_qos_req->list.prio) + update_target(o, &pm_qos_req->list, 0, temp); } EXPORT_SYMBOL_GPL(pm_qos_update_request); @@ -280,19 +284,15 @@ EXPORT_SYMBOL_GPL(pm_qos_update_request); */ void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req) { - unsigned long flags; - int qos_class; + struct pm_qos_object *o; 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_del(&pm_qos_req->list); + o = pm_qos_array[pm_qos_req->pm_qos_class]; + update_target(o, &pm_qos_req->list, 1, PM_QOS_DEFAULT_VALUE); kfree(pm_qos_req); - spin_unlock_irqrestore(&pm_qos_lock, flags); - update_target(qos_class); } EXPORT_SYMBOL_GPL(pm_qos_remove_request);