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PM: domains: Allocate governor data dynamically based on a genpd gove…
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…rnor

If a genpd doesn't have an associated governor assigned, several variables
in the struct generic_pm_domain becomes superfluous.

Rather than wasting memory in allocated genpds, let's move the variables
from the struct generic_pm_domain into a new separate struct. In this way,
we can instead dynamically decide when we need to allocate the
corresponding data for it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Ulf Hansson authored and Rafael J. Wysocki committed May 19, 2022
1 parent ba43d6d commit f38d1a6
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Showing 3 changed files with 70 additions and 41 deletions.
49 changes: 33 additions & 16 deletions drivers/base/power/domain.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -527,7 +527,8 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
goto out;

genpd->states[state_idx].power_on_latency_ns = elapsed_ns;
genpd->max_off_time_changed = true;
if (genpd->gd)
genpd->gd->max_off_time_changed = true;
pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
genpd->name, "on", elapsed_ns);

Expand Down Expand Up @@ -576,7 +577,8 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed)
goto out;

genpd->states[state_idx].power_off_latency_ns = elapsed_ns;
genpd->max_off_time_changed = true;
if (genpd->gd)
genpd->gd->max_off_time_changed = true;
pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n",
genpd->name, "off", elapsed_ns);

Expand Down Expand Up @@ -772,7 +774,7 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
dev = gpd_data->base.dev;

for (;;) {
struct generic_pm_domain *genpd;
struct generic_pm_domain *genpd = ERR_PTR(-ENODATA);
struct pm_domain_data *pdd;
struct gpd_timing_data *td;

Expand All @@ -782,18 +784,17 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
dev->power.subsys_data->domain_data : NULL;
if (pdd) {
td = to_gpd_data(pdd)->td;
if (td)
if (td) {
td->constraint_changed = true;
genpd = dev_to_genpd(dev);
} else {
genpd = ERR_PTR(-ENODATA);
genpd = dev_to_genpd(dev);
}
}

spin_unlock_irq(&dev->power.lock);

if (!IS_ERR(genpd)) {
genpd_lock(genpd);
genpd->max_off_time_changed = true;
genpd->gd->max_off_time_changed = true;
genpd_unlock(genpd);
}

Expand Down Expand Up @@ -922,7 +923,7 @@ static int genpd_runtime_suspend(struct device *dev)
td->suspend_latency_ns = elapsed_ns;
dev_dbg(dev, "suspend latency exceeded, %lld ns\n",
elapsed_ns);
genpd->max_off_time_changed = true;
genpd->gd->max_off_time_changed = true;
td->constraint_changed = true;
}
}
Expand Down Expand Up @@ -1002,7 +1003,7 @@ static int genpd_runtime_resume(struct device *dev)
td->resume_latency_ns = elapsed_ns;
dev_dbg(dev, "resume latency exceeded, %lld ns\n",
elapsed_ns);
genpd->max_off_time_changed = true;
genpd->gd->max_off_time_changed = true;
td->constraint_changed = true;
}
}
Expand Down Expand Up @@ -1617,6 +1618,7 @@ static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev)
static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
struct device *base_dev)
{
struct genpd_governor_data *gd = genpd->gd;
struct generic_pm_domain_data *gpd_data;
int ret;

Expand All @@ -1625,7 +1627,7 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(dev))
return -EINVAL;

gpd_data = genpd_alloc_dev_data(dev, genpd->gov);
gpd_data = genpd_alloc_dev_data(dev, gd);
if (IS_ERR(gpd_data))
return PTR_ERR(gpd_data);

Expand All @@ -1641,7 +1643,8 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
dev_pm_domain_set(dev, &genpd->domain);

genpd->device_count++;
genpd->max_off_time_changed = true;
if (gd)
gd->max_off_time_changed = true;

list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);

Expand Down Expand Up @@ -1695,7 +1698,8 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
}

genpd->device_count--;
genpd->max_off_time_changed = true;
if (genpd->gd)
genpd->gd->max_off_time_changed = true;

genpd_clear_cpumask(genpd, gpd_data->cpu);
dev_pm_domain_set(dev, NULL);
Expand Down Expand Up @@ -1970,24 +1974,39 @@ static int genpd_set_default_power_state(struct generic_pm_domain *genpd)

static int genpd_alloc_data(struct generic_pm_domain *genpd)
{
struct genpd_governor_data *gd = NULL;
int ret;

if (genpd_is_cpu_domain(genpd) &&
!zalloc_cpumask_var(&genpd->cpus, GFP_KERNEL))
return -ENOMEM;

if (genpd->gov) {
gd = kzalloc(sizeof(*gd), GFP_KERNEL);
if (!gd) {
ret = -ENOMEM;
goto free;
}

gd->max_off_time_ns = -1;
gd->max_off_time_changed = true;
gd->next_wakeup = KTIME_MAX;
}

/* Use only one "off" state if there were no states declared */
if (genpd->state_count == 0) {
ret = genpd_set_default_power_state(genpd);
if (ret)
goto free;
}

genpd->gd = gd;
return 0;

free:
if (genpd_is_cpu_domain(genpd))
free_cpumask_var(genpd->cpus);
kfree(gd);
return ret;
}

Expand All @@ -1997,6 +2016,7 @@ static void genpd_free_data(struct generic_pm_domain *genpd)
free_cpumask_var(genpd->cpus);
if (genpd->free_states)
genpd->free_states(genpd->states, genpd->state_count);
kfree(genpd->gd);
}

static void genpd_lock_init(struct generic_pm_domain *genpd)
Expand Down Expand Up @@ -2036,9 +2056,6 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
atomic_set(&genpd->sd_count, 0);
genpd->status = is_off ? GENPD_STATE_OFF : GENPD_STATE_ON;
genpd->device_count = 0;
genpd->max_off_time_ns = -1;
genpd->max_off_time_changed = true;
genpd->next_wakeup = KTIME_MAX;
genpd->provider = NULL;
genpd->has_provider = false;
genpd->accounting_time = ktime_get_mono_fast_ns();
Expand Down
48 changes: 28 additions & 20 deletions drivers/base/power/domain_governor.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,19 +146,21 @@ static void update_domain_next_wakeup(struct generic_pm_domain *genpd, ktime_t n
}

list_for_each_entry(link, &genpd->parent_links, parent_node) {
next_wakeup = link->child->next_wakeup;
struct genpd_governor_data *cgd = link->child->gd;

next_wakeup = cgd ? cgd->next_wakeup : KTIME_MAX;
if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
if (ktime_before(next_wakeup, domain_wakeup))
domain_wakeup = next_wakeup;
}

genpd->next_wakeup = domain_wakeup;
genpd->gd->next_wakeup = domain_wakeup;
}

static bool next_wakeup_allows_state(struct generic_pm_domain *genpd,
unsigned int state, ktime_t now)
{
ktime_t domain_wakeup = genpd->next_wakeup;
ktime_t domain_wakeup = genpd->gd->next_wakeup;
s64 idle_time_ns, min_sleep_ns;

min_sleep_ns = genpd->states[state].power_off_latency_ns +
Expand Down Expand Up @@ -188,8 +190,9 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
* All subdomains have been powered off already at this point.
*/
list_for_each_entry(link, &genpd->parent_links, parent_node) {
struct generic_pm_domain *sd = link->child;
s64 sd_max_off_ns = sd->max_off_time_ns;
struct genpd_governor_data *cgd = link->child->gd;

s64 sd_max_off_ns = cgd ? cgd->max_off_time_ns : -1;

if (sd_max_off_ns < 0)
continue;
Expand Down Expand Up @@ -247,7 +250,7 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
* time and the time needed to turn the domain on is the maximum
* theoretical time this domain can spend in the "off" state.
*/
genpd->max_off_time_ns = min_off_time_ns -
genpd->gd->max_off_time_ns = min_off_time_ns -
genpd->states[state].power_on_latency_ns;
return true;
}
Expand All @@ -262,6 +265,7 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
{
struct generic_pm_domain *genpd = pd_to_genpd(pd);
struct genpd_governor_data *gd = genpd->gd;
int state_idx = genpd->state_count - 1;
struct gpd_link *link;

Expand All @@ -272,26 +276,26 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
* cannot be met.
*/
update_domain_next_wakeup(genpd, now);
if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (genpd->next_wakeup != KTIME_MAX)) {
if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (gd->next_wakeup != KTIME_MAX)) {
/* Let's find out the deepest domain idle state, the devices prefer */
while (state_idx >= 0) {
if (next_wakeup_allows_state(genpd, state_idx, now)) {
genpd->max_off_time_changed = true;
gd->max_off_time_changed = true;
break;
}
state_idx--;
}

if (state_idx < 0) {
state_idx = 0;
genpd->cached_power_down_ok = false;
gd->cached_power_down_ok = false;
goto done;
}
}

if (!genpd->max_off_time_changed) {
genpd->state_idx = genpd->cached_power_down_state_idx;
return genpd->cached_power_down_ok;
if (!gd->max_off_time_changed) {
genpd->state_idx = gd->cached_power_down_state_idx;
return gd->cached_power_down_ok;
}

/*
Expand All @@ -300,29 +304,33 @@ static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
* going to be called for any parent until this instance
* returns.
*/
list_for_each_entry(link, &genpd->child_links, child_node)
link->parent->max_off_time_changed = true;
list_for_each_entry(link, &genpd->child_links, child_node) {
struct genpd_governor_data *pgd = link->parent->gd;

if (pgd)
pgd->max_off_time_changed = true;
}

genpd->max_off_time_ns = -1;
genpd->max_off_time_changed = false;
genpd->cached_power_down_ok = true;
gd->max_off_time_ns = -1;
gd->max_off_time_changed = false;
gd->cached_power_down_ok = true;

/*
* Find a state to power down to, starting from the state
* determined by the next wakeup.
*/
while (!__default_power_down_ok(pd, state_idx)) {
if (state_idx == 0) {
genpd->cached_power_down_ok = false;
gd->cached_power_down_ok = false;
break;
}
state_idx--;
}

done:
genpd->state_idx = state_idx;
genpd->cached_power_down_state_idx = genpd->state_idx;
return genpd->cached_power_down_ok;
gd->cached_power_down_state_idx = genpd->state_idx;
return gd->cached_power_down_ok;
}

static bool default_power_down_ok(struct dev_pm_domain *pd)
Expand Down
14 changes: 9 additions & 5 deletions include/linux/pm_domain.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,14 @@ struct gpd_dev_ops {
int (*stop)(struct device *dev);
};

struct genpd_governor_data {
s64 max_off_time_ns;
bool max_off_time_changed;
ktime_t next_wakeup;
bool cached_power_down_ok;
bool cached_power_down_state_idx;
};

struct genpd_power_state {
s64 power_off_latency_ns;
s64 power_on_latency_ns;
Expand All @@ -114,6 +122,7 @@ struct generic_pm_domain {
struct list_head child_links; /* Links with PM domain as a child */
struct list_head dev_list; /* List of devices */
struct dev_power_governor *gov;
struct genpd_governor_data *gd; /* Data used by a genpd governor. */
struct work_struct power_off_work;
struct fwnode_handle *provider; /* Identity of the domain provider */
bool has_provider;
Expand All @@ -134,11 +143,6 @@ struct generic_pm_domain {
int (*set_performance_state)(struct generic_pm_domain *genpd,
unsigned int state);
struct gpd_dev_ops dev_ops;
s64 max_off_time_ns; /* Maximum allowed "suspended" time. */
ktime_t next_wakeup; /* Maintained by the domain governor */
bool max_off_time_changed;
bool cached_power_down_ok;
bool cached_power_down_state_idx;
int (*attach_dev)(struct generic_pm_domain *domain,
struct device *dev);
void (*detach_dev)(struct generic_pm_domain *domain,
Expand Down

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