Skip to content

Commit

Permalink
pm_qos: Reimplement using plists
Browse files Browse the repository at this point in the history 
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 <James.Bottomley@suse.de>
Signed-off-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
  • Loading branch information
James Bottomley authored and Rafael J. Wysocki committed Jul 19, 2010
1 parent 12e4d0c commit 5f27984
Showing 1 changed file with 86 additions and 86 deletions.
172 changes: 86 additions & 86 deletions kernel/pm_qos_params.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@
/*#define DEBUG*/

#include <linux/pm_qos_params.h>
#include <linux/plist.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
Expand All @@ -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,
};


Expand All @@ -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);
Expand All @@ -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)
Expand Down Expand Up @@ -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);

Expand All @@ -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;
Expand All @@ -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);

Expand All @@ -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);

Expand Down

0 comments on commit 5f27984

Please sign in to comment.