[PATCH v2] PM / wakeup: show wakeup sources stats in sysfs

Tri Vo
2019-06-27T22:54:30Z

Userspace can use wakeup_sources debugfs node to plot history of suspend
blocking wakeup sources over device's boot cycle. This information can
then be used (1) for power-specific bug reporting and (2) towards
attributing battery consumption to specific processes over a period of
time.

However, debugfs doesn't have stable ABI. For this reason, expose wakeup
sources statistics in sysfs under /sys/power/wakeup_sources/<name>/

Embedding a struct kobject into struct wakeup_source changes lifetime
requirements on the latter. To that end, change deallocation of struct
wakeup_source using kfree to kobject_put().

Change struct wakelock's wakeup_source member to a pointer to decouple
lifetimes of struct wakelock and struct wakeup_source for above reason.

Introduce CONFIG_PM_SLEEP_STATS that enables/disables showing wakeup
source statistics in sysfs.

Signed-off-by: Tri Vo <trong@android.com>
---
Documentation/ABI/testing/sysfs-power | 80 ++++++++++-
drivers/base/power/Makefile | 2 +-
drivers/base/power/power.h | 7 +
drivers/base/power/wakeup.c | 16 ++-
drivers/base/power/wakeup_stats.c | 194 ++++++++++++++++++++++++++
include/linux/pm_wakeup.h | 15 ++
kernel/power/Kconfig | 10 ++
kernel/power/wakelock.c | 42 ++++--
8 files changed, 347 insertions(+), 19 deletions(-)
create mode 100644 drivers/base/power/wakeup_stats.c

v2:
- Updated Documentation/ABI/, as per Greg.
- Removed locks in attribute functions, as per Greg.
- Lifetimes of struct wakelock and struck wakeup_source are now different due to
the latter embedding a refcounted kobject. Changed it so that struct wakelock
only has a pointer to struct wakeup_source, instead of embedding it.
- Added CONFIG_PM_SLEEP_STATS that enables/disables wakeup source statistics in
sysfs.

diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index 18b7dc929234..ba35f1eef73b 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -300,4 +300,82 @@ Description:
attempt.

Using this sysfs file will override any values that were
- set using the kernel command line for disk offset.
\ No newline at end of file
+ set using the kernel command line for disk offset.
+
+What: /sys/power/wakeup_sources/.../
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../ directory contains attributes
+ that expose statistics about a given wakeup source to user
+ space. Attributes in this directory are read-only.
+
+What: /sys/power/wakeup_sources/.../active_count
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../active_count file contains the
+ number of times the wakeup source was activated.
+
+What: /sys/power/wakeup_sources/.../event_count
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../event_count file contains the
+ number of signaled wakeup events associated with the wakeup
+ source.
+
+What: /sys/power/wakeup_sources/.../wakeup_count
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../wakeup_count file contains the
+ number of times the wakeup source might abort suspend.
+
+What: /sys/power/wakeup_sources/.../expire_count
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../expire_count file contains the
+ number of times the wakeup source's timeout has expired.
+
+What: /sys/power/wakeup_sources/.../active_time_ms
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../active_time_ms file contains
+ the amount of time the wakeup source has been continuously
+ active, in milliseconds. If the wakeup source is not active,
+ this file contains '0'.
+
+What: /sys/power/wakeup_sources/.../total_time_ms
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../total_time_ms file contains
+ the total amount of time this wakeup source has been active, in
+ milliseconds.
+
+What: /sys/power/wakeup_sources/.../max_time_ms
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../max_time_ms file contains the
+ maximum amount of time this wakeup source has been continuously
+ active, in milliseconds.
+
+What: /sys/power/wakeup_sources/.../last_change_ms
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../last_change_ms file contains
+ the monotonic clock time when the wakeup source was touched last
+ time, in milliseconds.
+
+What: /sys/power/wakeup_sources/.../prevent_suspend_time_ms
+Date: June 2019
+Contact: Tri Vo <trong@android.com>
+Description:
+ The /sys/power/wakeup_sources/.../prevent_suspend_time_ms file
+ contains the total amount of time this wakeup source has been
+ preventing autosleep, in milliseconds.
diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index e1bb691cf8f1..ec5bb190b9d0 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_PM) += sysfs.o generic_ops.o common.o qos.o runtime.o wakeirq.o
-obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o
+obj-$(CONFIG_PM_SLEEP) += main.o wakeup.o wakeup_stats.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
obj-$(CONFIG_PM_GENERIC_DOMAINS) += domain.o domain_governor.o
obj-$(CONFIG_HAVE_CLK) += clock_ops.o
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index ec33fbdb919b..c288298f57c0 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -149,3 +149,10 @@ static inline void device_pm_init(struct device *dev)
device_pm_sleep_init(dev);
pm_runtime_init(dev);
}
+
+#ifdef CONFIG_PM_SLEEP
+
+/* drivers/base/power/wakeup_stats.c */
+extern struct kobj_type wakeup_source_ktype;
+
+#endif /* CONFIG_PM_SLEEP */
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 5b2b6a05a4f3..620c87923a3e 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -102,6 +102,9 @@ struct wakeup_source *wakeup_source_create(const char *name)
return NULL;

wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
+
+ kobject_init(&ws->kobj, &wakeup_source_ktype);
+
return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_create);
@@ -147,8 +150,7 @@ void wakeup_source_destroy(struct wakeup_source *ws)

__pm_relax(ws);
wakeup_source_record(ws);
- kfree_const(ws->name);
- kfree(ws);
+ kobject_put(&ws->kobj);
}
EXPORT_SYMBOL_GPL(wakeup_source_destroy);

@@ -205,11 +207,17 @@ EXPORT_SYMBOL_GPL(wakeup_source_remove);
struct wakeup_source *wakeup_source_register(const char *name)
{
struct wakeup_source *ws;
+ int ret;

ws = wakeup_source_create(name);
- if (ws)
+ if (ws) {
+ ret = wakeup_source_sysfs_add(ws);
+ if (ret) {
+ kobject_put(&ws->kobj);
+ return NULL;
+ }
wakeup_source_add(ws);
-
+ }
return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_register);
diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
new file mode 100644
index 000000000000..05ab8283ed66
--- /dev/null
+++ b/drivers/base/power/wakeup_stats.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/slab.h>
+
+#include "power.h"
+
+struct wakeup_source_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr, char *buf);
+ ssize_t (*store)(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr, const char *buf,
+ size_t count);
+};
+
+#define to_wakeup_source_obj(x) container_of(x, struct wakeup_source, kobj)
+#define to_wakeup_source_attr(x) \
+ container_of(x, struct wakeup_source_attribute, attr)
+
+static ssize_t wakeup_source_attr_show(struct kobject *kobj,
+ struct attribute *attr,
+ char *buf)
+{
+ struct wakeup_source_attribute *attribute;
+ struct wakeup_source *ws;
+
+ ws = to_wakeup_source_obj(kobj);
+ attribute = to_wakeup_source_attr(attr);
+
+ if (!attribute->show)
+ return -EIO;
+
+ return attribute->show(ws, attribute, buf);
+}
+
+static const struct sysfs_ops wakeup_source_sysfs_ops = {
+ .show = wakeup_source_attr_show,
+};
+
+static void wakeup_source_release(struct kobject *kobj)
+{
+ struct wakeup_source *ws;
+
+ ws = to_wakeup_source_obj(kobj);
+ kfree_const(ws->name);
+ kfree(ws);
+}
+
+static ssize_t wakeup_source_count_show(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr,
+ char *buf)
+{
+ unsigned long var;
+
+ if (strcmp(attr->attr.name, "active_count") == 0)
+ var = ws->active_count;
+ else if (strcmp(attr->attr.name, "event_count") == 0)
+ var = ws->event_count;
+ else if (strcmp(attr->attr.name, "wakeup_count") == 0)
+ var = ws->wakeup_count;
+ else
+ var = ws->expire_count;
+
+ return sprintf(buf, "%lu\n", var);
+}
+
+#define wakeup_source_count_attr(_name) \
+static struct wakeup_source_attribute _name##_attr = { \
+ .attr = { \
+ .name = __stringify(_name), \
+ .mode = 0444, \
+ }, \
+ .show = wakeup_source_count_show, \
+}
+
+wakeup_source_count_attr(active_count);
+wakeup_source_count_attr(event_count);
+wakeup_source_count_attr(wakeup_count);
+wakeup_source_count_attr(expire_count);
+
+#define wakeup_source_attr(_name) \
+static struct wakeup_source_attribute _name##_attr = __ATTR_RO(_name)
+
+static ssize_t active_time_ms_show(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr,
+ char *buf)
+{
+ ktime_t active_time =
+ ws->active ? ktime_sub(ktime_get(), ws->last_time) : 0;
+ return sprintf(buf, "%lld\n", ktime_to_ms(active_time));
+}
+wakeup_source_attr(active_time_ms);
+
+static ssize_t total_time_ms_show(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr,
+ char *buf)
+{
+ ktime_t active_time;
+ ktime_t total_time = ws->total_time;
+
+ if (ws->active) {
+ active_time = ktime_sub(ktime_get(), ws->last_time);
+ total_time = ktime_add(total_time, active_time);
+ }
+ return sprintf(buf, "%lld\n", ktime_to_ms(total_time));
+}
+wakeup_source_attr(total_time_ms);
+
+static ssize_t max_time_ms_show(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr,
+ char *buf)
+{
+ ktime_t active_time;
+ ktime_t max_time = ws->max_time;
+
+ if (ws->active) {
+ active_time = ktime_sub(ktime_get(), ws->last_time);
+ if (active_time > max_time)
+ max_time = active_time;
+ }
+ return sprintf(buf, "%lld\n", ktime_to_ms(max_time));
+}
+wakeup_source_attr(max_time_ms);
+
+static ssize_t last_change_ms_show(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%lld\n", ktime_to_ms(ws->last_time));
+}
+wakeup_source_attr(last_change_ms);
+
+static ssize_t prevent_suspend_time_ms_show(struct wakeup_source *ws,
+ struct wakeup_source_attribute *attr,
+ char *buf)
+{
+ ktime_t prevent_sleep_time = ws->prevent_sleep_time;
+
+ if (ws->active && ws->autosleep_enabled) {
+ prevent_sleep_time = ktime_add(prevent_sleep_time,
+ ktime_sub(ktime_get(), ws->start_prevent_time));
+ }
+ return sprintf(buf, "%lld\n", ktime_to_ms(prevent_sleep_time));
+}
+wakeup_source_attr(prevent_suspend_time_ms);
+
+static struct attribute *wakeup_source_default_attrs[] = {
+ &active_count_attr.attr,
+ &event_count_attr.attr,
+ &wakeup_count_attr.attr,
+ &expire_count_attr.attr,
+ &active_time_ms_attr.attr,
+ &total_time_ms_attr.attr,
+ &max_time_ms_attr.attr,
+ &last_change_ms_attr.attr,
+ &prevent_suspend_time_ms_attr.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(wakeup_source_default);
+
+struct kobj_type wakeup_source_ktype = {
+ .sysfs_ops = &wakeup_source_sysfs_ops,
+ .release = wakeup_source_release,
+ .default_groups = wakeup_source_default_groups,
+};
+
+#ifdef CONFIG_PM_SLEEP_STATS
+
+static struct kset *wakeup_source_kset;
+
+/**
+ * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
+ * @ws: Wakeup source to be exposed in sysfs.
+ */
+int wakeup_source_sysfs_add(struct wakeup_source *ws)
+{
+ ws->kobj.kset = wakeup_source_kset;
+ return kobject_add(&ws->kobj, NULL, "%s", ws->name);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_sysfs_add);
+
+static int __init wakeup_sources_sysfs_init(void)
+{
+ wakeup_source_kset = kset_create_and_add("wakeup_sources", NULL,
+ power_kobj);
+ if (!wakeup_source_kset)
+ return -ENOMEM;
+
+ return 0;
+}
+
+postcore_initcall(wakeup_sources_sysfs_init);
+
+#endif /* !CONFIG_PM_SLEEP_STATS */
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index ce57771fab9b..67026c52975c 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -57,6 +57,7 @@ struct wakeup_source {
unsigned long wakeup_count;
bool active:1;
bool autosleep_enabled:1;
+ struct kobject kobj;
};

#ifdef CONFIG_PM_SLEEP
@@ -181,6 +182,20 @@ static inline void pm_wakeup_dev_event(struct device *dev, unsigned int msec,

#endif /* !CONFIG_PM_SLEEP */

+#ifdef CONFIG_PM_SLEEP_STATS
+
+/* drivers/base/power/wakeup_stats.c */
+extern int wakeup_source_sysfs_add(struct wakeup_source *ws);
+
+#else /* !CONFIG_PM_SLEEP_STATS */
+
+static inline int wakeup_source_sysfs_add(struct wakeup_source *ws)
+{
+ return 0;
+}
+
+#endif /* !CONFIG_PM_SLEEP_STATS */
+
static inline void wakeup_source_init(struct wakeup_source *ws,
const char *name)
{
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index ff8592ddedee..4d258f34020b 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -195,6 +195,16 @@ config PM_SLEEP_DEBUG
def_bool y
depends on PM_DEBUG && PM_SLEEP

+config PM_SLEEP_STATS
+ bool "Wakeup sources statistics"
+ depends on PM_SLEEP
+ help
+ Expose wakeup sources statistics to user space via sysfs. Collected
+ statistics are located under /sys/power/wakeup_sources. For more
+ information, read <file:Documentation/ABI/testing/sysfs-power>.
+
+ If in doubt, say N.
+
config DPM_WATCHDOG
bool "Device suspend/resume watchdog"
depends on PM_DEBUG && PSTORE && EXPERT
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index 4210152e56f0..eebbc537321f 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -27,7 +27,7 @@ static DEFINE_MUTEX(wakelocks_lock);
struct wakelock {
char *name;
struct rb_node node;
- struct wakeup_source ws;
+ struct wakeup_source *ws;
#ifdef CONFIG_PM_WAKELOCKS_GC
struct list_head lru;
#endif
@@ -46,7 +46,7 @@ ssize_t pm_show_wakelocks(char *buf, bool show_active)

for (node = rb_first(&wakelocks_tree); node; node = rb_next(node)) {
wl = rb_entry(node, struct wakelock, node);
- if (wl->ws.active == show_active)
+ if (wl->ws->active == show_active)
str += scnprintf(str, end - str, "%s ", wl->name);
}
if (str > buf)
@@ -112,18 +112,19 @@ static void __wakelocks_gc(struct work_struct *work)
u64 idle_time_ns;
bool active;

- spin_lock_irq(&wl->ws.lock);
- idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws.last_time));
- active = wl->ws.active;
- spin_unlock_irq(&wl->ws.lock);
+ spin_lock_irq(&wl->ws->lock);
+ idle_time_ns = ktime_to_ns(ktime_sub(now, wl->ws->last_time));
+ active = wl->ws->active;
+ spin_unlock_irq(&wl->ws->lock);

if (idle_time_ns < ((u64)WL_GC_TIME_SEC * NSEC_PER_SEC))
break;

if (!active) {
- wakeup_source_remove(&wl->ws);
+ wakeup_source_remove(wl->ws);
rb_erase(&wl->node, &wakelocks_tree);
list_del(&wl->lru);
+ kobject_put(&wl->ws->kobj);
kfree(wl->name);
kfree(wl);
decrement_wakelocks_number();
@@ -153,6 +154,7 @@ static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
struct rb_node **node = &wakelocks_tree.rb_node;
struct rb_node *parent = *node;
struct wakelock *wl;
+ int ret;

while (*node) {
int diff;
@@ -187,9 +189,23 @@ static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
kfree(wl);
return ERR_PTR(-ENOMEM);
}
- wl->ws.name = wl->name;
- wl->ws.last_time = ktime_get();
- wakeup_source_add(&wl->ws);
+
+ wl->ws = wakeup_source_create(wl->name);
+ if (!wl->ws) {
+ kfree(wl);
+ return ERR_PTR(-ENOMEM);
+ }
+ wl->ws->last_time = ktime_get();
+
+ ret = wakeup_source_sysfs_add(wl->ws);
+ if (ret) {
+ kobject_put(&wl->ws->kobj);
+ kfree(wl->name);
+ kfree(wl);
+ return ERR_PTR(ret);
+ }
+
+ wakeup_source_add(wl->ws);
rb_link_node(&wl->node, parent, node);
rb_insert_color(&wl->node, &wakelocks_tree);
wakelocks_lru_add(wl);
@@ -233,9 +249,9 @@ int pm_wake_lock(const char *buf)
u64 timeout_ms = timeout_ns + NSEC_PER_MSEC - 1;

do_div(timeout_ms, NSEC_PER_MSEC);
- __pm_wakeup_event(&wl->ws, timeout_ms);
+ __pm_wakeup_event(wl->ws, timeout_ms);
} else {
- __pm_stay_awake(&wl->ws);
+ __pm_stay_awake(wl->ws);
}

wakelocks_lru_most_recent(wl);
@@ -271,7 +287,7 @@ int pm_wake_unlock(const char *buf)
ret = PTR_ERR(wl);
goto out;
}
- __pm_relax(&wl->ws);
+ __pm_relax(wl->ws);

wakelocks_lru_most_recent(wl);
wakelocks_gc();
--
2.22.0.410.gd8fdbe21b5-goog