[PATCH v8 0/3] PM / wakeup: Show wakeup sources stats in sysfs

[PATCH v8 0/3] PM / wakeup: Show wakeup sources stats in sysfs

[Tri Vo]

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, create a
'struct device' to expose wakeup sources statistics in sysfs under
/sys/class/wakeup/wakeup<ID>/*.

Patch 1 and 2 do some cleanup to simplify our changes to how wakeup sources are
created. Patch 3 implements wakeup sources stats in sysfs.

Tri Vo (3):
  PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()
  PM / wakeup: Use wakeup_source_register() in wakelock.c
  PM / wakeup: Show wakeup sources stats in sysfs

 Documentation/ABI/testing/sysfs-class-wakeup |  76 +++++++
 drivers/acpi/device_pm.c                     |   3 +-
 drivers/base/power/Makefile                  |   2 +-
 drivers/base/power/power.h                   |   9 +
 drivers/base/power/wakeup.c                  |  59 +++---
 drivers/base/power/wakeup_stats.c            | 203 +++++++++++++++++++
 fs/eventpoll.c                               |   4 +-
 include/linux/pm_wakeup.h                    |  21 +-
 kernel/power/autosleep.c                     |   2 +-
 kernel/power/wakelock.c                      |  32 +--
 kernel/time/alarmtimer.c                     |   2 +-
 11 files changed, 358 insertions(+), 55 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-wakeup
 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.

v3:
Changes by Greg:
- Reworked code to use 'struct device' instead of raw kobjects.
- Updated documentation file.
- Only link wakeup_stats.o when CONFIG_PM_SLEEP_STATS is enabled.
Changes by Tri:
- Reverted changes to kernel/power/wakelock.c. 'struct device' hides kobject
  operations. So no need to handle lifetimes in wakelock.c

v4:
- Added 'Co-developed-by:' and 'Tested-by:' fields to commit message.
- Moved new documentation to a separate file
  Documentation/ABI/testing/sysfs-class-wakeup, as per Greg.
- Fixed copyright header in drivers/base/power/wakeup_stats.c, as per Greg.

v5:
- Removed CONFIG_PM_SLEEP_STATS
- Used PTR_ERR_OR_ZERO instead of if(IS_ERR(...)) + PTR_ERR, reported by
  kbuild test robot <lkp@intel.com>
- Stephen reported that a call to device_init_wakeup() and writing 'enabled' to
  that device's power/wakeup file results in multiple wakeup source being
  allocated for that device.  Changed device_wakeup_enable() to check if device
  wakeup was previously enabled.
Changes by Stephen:
- Changed stats location from /sys/class/wakeup/<name>/* to
  /sys/class/wakeup/wakeup<ID>/*, where ID is an IDA-allocated integer. This
  avoids name collisions in /sys/class/wakeup/ directory.
- Added a "name" attribute to wakeup sources, and updated documentation.
- Device registering the wakeup source is now the parent of the wakeup source.
  Updated wakeup_source_register()'s signature and its callers accordingly.

v6:
- Changed stats location to /sys/class/wakeup/ws<ID>/*
- Replaced ida_simple_get()/ida_simple_remove() with ida_alloc()/ida_free() as
  the former is deprecated.
- Reverted changes to device_init_wakeup(). Rafael is preparing a patch to deal
  with extra wakeup source allocation in a separate patch.

v7:
- Removed wakeup_source_init(), wakeup_source_prepare().
- Removed duplicate wakeup source creation code from  kernel/power/wakelock.
- Moved ID allocation to wakeup source object creation time.
- Changed stats location back to /sys/class/wakeup/wakeup<ID>/*
- Remove wakeup source device's "power" attributes.

v8:
- Updated commit message on patch 1 to indicate change of behavior of
  wakeup_source_create(), as per Stephen.
- Included headers for used symbols, as per Stephen.
- Added a function to create wakeup source devices to use
  device_set_pm_not_required() to skip power management for such devices, as per
  Stephen.

--
2.22.0.770.g0f2c4a37fd-goog

[PATCH v8 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Tri Vo]

wakeup_source_init() has no users. Remove it.

As a result, wakeup_source_prepare() is only called from
wakeup_source_create(). Merge wakeup_source_prepare() into
wakeup_source_create() and remove it.

Change wakeup_source_create() behavior so that assigning NULL to wakeup
source's name throws an error.

Signed-off-by: Tri Vo <trong@android.com>
---
 drivers/base/power/wakeup.c | 33 +++++++++++++--------------------
 include/linux/pm_wakeup.h   | 11 -----------
 2 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index ee31d4f8d856..3938892c8903 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -72,23 +72,6 @@ static struct wakeup_source deleted_ws = {
 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
 };
 
-/**
- * wakeup_source_prepare - Prepare a new wakeup source for initialization.
- * @ws: Wakeup source to prepare.
- * @name: Pointer to the name of the new wakeup source.
- *
- * Callers must ensure that the @name string won't be freed when @ws is still in
- * use.
- */
-void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
-{
-	if (ws) {
-		memset(ws, 0, sizeof(*ws));
-		ws->name = name;
-	}
-}
-EXPORT_SYMBOL_GPL(wakeup_source_prepare);
-
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
@@ -96,13 +79,23 @@ EXPORT_SYMBOL_GPL(wakeup_source_prepare);
 struct wakeup_source *wakeup_source_create(const char *name)
 {
 	struct wakeup_source *ws;
+	const char *ws_name;
 
-	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
+	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
 	if (!ws)
-		return NULL;
+		goto err_ws;
+
+	ws_name = kstrdup_const(name, GFP_KERNEL);
+	if (!ws_name)
+		goto err_name;
+	ws->name = ws_name;
 
-	wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
 	return ws;
+
+err_name:
+	kfree(ws);
+err_ws:
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_create);
 
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index 91027602d137..c0cad2d8f800 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -81,7 +81,6 @@ static inline void device_set_wakeup_path(struct device *dev)
 }
 
 /* drivers/base/power/wakeup.c */
-extern void wakeup_source_prepare(struct wakeup_source *ws, const char *name);
 extern struct wakeup_source *wakeup_source_create(const char *name);
 extern void wakeup_source_destroy(struct wakeup_source *ws);
 extern void wakeup_source_add(struct wakeup_source *ws);
@@ -112,9 +111,6 @@ static inline bool device_can_wakeup(struct device *dev)
 	return dev->power.can_wakeup;
 }
 
-static inline void wakeup_source_prepare(struct wakeup_source *ws,
-					 const char *name) {}
-
 static inline struct wakeup_source *wakeup_source_create(const char *name)
 {
 	return NULL;
@@ -181,13 +177,6 @@ static inline void pm_wakeup_dev_event(struct device *dev, unsigned int msec,
 
 #endif /* !CONFIG_PM_SLEEP */
 
-static inline void wakeup_source_init(struct wakeup_source *ws,
-				      const char *name)
-{
-	wakeup_source_prepare(ws, name);
-	wakeup_source_add(ws);
-}
-
 static inline void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
 {
 	return pm_wakeup_ws_event(ws, msec, false);
-- 
2.22.0.770.g0f2c4a37fd-goog

Re: [PATCH v8 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Greg KH]

On Tue, Aug 06, 2019 at 06:48:44PM -0700, Tri Vo wrote:
> wakeup_source_init() has no users. Remove it.
> 
> As a result, wakeup_source_prepare() is only called from
> wakeup_source_create(). Merge wakeup_source_prepare() into
> wakeup_source_create() and remove it.
> 
> Change wakeup_source_create() behavior so that assigning NULL to wakeup
> source's name throws an error.

The kernel C code can not "throw" errors :)

Anyway, odd verbage asside, patch looks good to me:

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH v8 1/3] PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()

[Stephen Boyd]

Quoting Tri Vo (2019-08-06 18:48:44)
> wakeup_source_init() has no users. Remove it.
> 
> As a result, wakeup_source_prepare() is only called from
> wakeup_source_create(). Merge wakeup_source_prepare() into
> wakeup_source_create() and remove it.
> 
> Change wakeup_source_create() behavior so that assigning NULL to wakeup
> source's name throws an error.
> 
> Signed-off-by: Tri Vo <trong@android.com>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>

[PATCH v8 2/3] PM / wakeup: Use wakeup_source_register() in wakelock.c

[Tri Vo]

kernel/power/wakelock.c duplicates wakeup source creation and
registration code from drivers/base/power/wakeup.c.

Change struct wakelock's wakeup source to a pointer and use
wakeup_source_register() function to create and register said wakeup
source. Use wakeup_source_unregister() on cleanup path.

Signed-off-by: Tri Vo <trong@android.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---
 kernel/power/wakelock.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index 4210152e56f0..d1eb7fd98b64 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)
@@ -112,16 +112,16 @@ 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_unregister(wl->ws);
 			rb_erase(&wl->node, &wakelocks_tree);
 			list_del(&wl->lru);
 			kfree(wl->name);
@@ -187,9 +187,15 @@ 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_register(wl->name);
+	if (!wl->ws) {
+		kfree(wl->name);
+		kfree(wl);
+		return ERR_PTR(-ENOMEM);
+	}
+	wl->ws->last_time = ktime_get();
+
 	rb_link_node(&wl->node, parent, node);
 	rb_insert_color(&wl->node, &wakelocks_tree);
 	wakelocks_lru_add(wl);
@@ -233,9 +239,9 @@ 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 +277,7 @@ 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();
-- 
2.22.0.770.g0f2c4a37fd-goog

Re: [PATCH v8 2/3] PM / wakeup: Use wakeup_source_register() in wakelock.c

[Greg KH]

On Tue, Aug 06, 2019 at 06:48:45PM -0700, Tri Vo wrote:
> kernel/power/wakelock.c duplicates wakeup source creation and
> registration code from drivers/base/power/wakeup.c.
> 
> Change struct wakelock's wakeup source to a pointer and use
> wakeup_source_register() function to create and register said wakeup
> source. Use wakeup_source_unregister() on cleanup path.
> 
> Signed-off-by: Tri Vo <trong@android.com>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> ---
>  kernel/power/wakelock.c | 32 +++++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 13 deletions(-)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[PATCH v8 3/3] PM / wakeup: Show wakeup sources stats in sysfs

[Tri Vo]

Add an ID and a device pointer to 'struct wakeup_source'. Use them to to
expose wakeup sources statistics in sysfs under
/sys/class/wakeup/wakeup<ID>/*.

Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Tri Vo <trong@android.com>
Tested-by: Tri Vo <trong@android.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
---
 Documentation/ABI/testing/sysfs-class-wakeup |  76 +++++++
 drivers/acpi/device_pm.c                     |   3 +-
 drivers/base/power/Makefile                  |   2 +-
 drivers/base/power/power.h                   |   9 +
 drivers/base/power/wakeup.c                  |  28 ++-
 drivers/base/power/wakeup_stats.c            | 203 +++++++++++++++++++
 fs/eventpoll.c                               |   4 +-
 include/linux/pm_wakeup.h                    |  10 +-
 kernel/power/autosleep.c                     |   2 +-
 kernel/power/wakelock.c                      |   2 +-
 kernel/time/alarmtimer.c                     |   2 +-
 11 files changed, 328 insertions(+), 13 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-wakeup
 create mode 100644 drivers/base/power/wakeup_stats.c

diff --git a/Documentation/ABI/testing/sysfs-class-wakeup b/Documentation/ABI/testing/sysfs-class-wakeup
new file mode 100644
index 000000000000..754aab8b6dcd
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-wakeup
@@ -0,0 +1,76 @@
+What:		/sys/class/wakeup/
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		The /sys/class/wakeup/ directory contains pointers to all
+		wakeup sources in the kernel at that moment in time.
+
+What:		/sys/class/wakeup/.../name
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the name of the wakeup source.
+
+What:		/sys/class/wakeup/.../active_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of times the wakeup source was
+		activated.
+
+What:		/sys/class/wakeup/.../event_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of signaled wakeup events
+		associated with the wakeup source.
+
+What:		/sys/class/wakeup/.../wakeup_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of times the wakeup source might
+		abort suspend.
+
+What:		/sys/class/wakeup/.../expire_count
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the number of times the wakeup source's
+		timeout has expired.
+
+What:		/sys/class/wakeup/.../active_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This 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/class/wakeup/.../total_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the total amount of time this wakeup source
+		has been active, in milliseconds.
+
+What:		/sys/class/wakeup/.../max_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the maximum amount of time this wakeup
+		source has been continuously active, in milliseconds.
+
+What:		/sys/class/wakeup/.../last_change_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		This file contains the monotonic clock time when the wakeup
+		source was touched last time, in milliseconds.
+
+What:		/sys/class/wakeup/.../prevent_suspend_time_ms
+Date:		June 2019
+Contact:	Tri Vo <trong@android.com>
+Description:
+		The file contains the total amount of time this wakeup source
+		has been preventing autosleep, in milliseconds.
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 28cffaaf9d82..91634e2dba8a 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -495,7 +495,8 @@ acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,
 		goto out;
 
 	mutex_lock(&acpi_pm_notifier_lock);
-	adev->wakeup.ws = wakeup_source_register(dev_name(&adev->dev));
+	adev->wakeup.ws = wakeup_source_register(&adev->dev,
+						 dev_name(&adev->dev));
 	adev->wakeup.context.dev = dev;
 	adev->wakeup.context.func = func;
 	adev->wakeup.flags.notifier_present = true;
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..57b1d1d88c8e 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -149,3 +149,12 @@ 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 int wakeup_source_sysfs_add(struct device *parent,
+				   struct wakeup_source *ws);
+extern void wakeup_source_sysfs_remove(struct wakeup_source *ws);
+
+#endif /* CONFIG_PM_SLEEP */
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 3938892c8903..973675f24314 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -72,6 +72,8 @@ static struct wakeup_source deleted_ws = {
 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
 };
 
+static DEFINE_IDA(wakeup_ida);
+
 /**
  * wakeup_source_create - Create a struct wakeup_source object.
  * @name: Name of the new wakeup source.
@@ -80,6 +82,7 @@ struct wakeup_source *wakeup_source_create(const char *name)
 {
 	struct wakeup_source *ws;
 	const char *ws_name;
+	int id;
 
 	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
 	if (!ws)
@@ -90,8 +93,15 @@ struct wakeup_source *wakeup_source_create(const char *name)
 		goto err_name;
 	ws->name = ws_name;
 
+	id = ida_alloc(&wakeup_ida, GFP_KERNEL);
+	if (id < 0)
+		goto err_id;
+	ws->id = id;
+
 	return ws;
 
+err_id:
+	kfree_const(ws->name);
 err_name:
 	kfree(ws);
 err_ws:
@@ -140,6 +150,7 @@ void wakeup_source_destroy(struct wakeup_source *ws)
 
 	__pm_relax(ws);
 	wakeup_source_record(ws);
+	ida_free(&wakeup_ida, ws->id);
 	kfree_const(ws->name);
 	kfree(ws);
 }
@@ -193,16 +204,24 @@ EXPORT_SYMBOL_GPL(wakeup_source_remove);
 
 /**
  * wakeup_source_register - Create wakeup source and add it to the list.
+ * @dev: Device this wakeup source is associated with (or NULL if virtual).
  * @name: Name of the wakeup source to register.
  */
-struct wakeup_source *wakeup_source_register(const char *name)
+struct wakeup_source *wakeup_source_register(struct device *dev,
+					     const char *name)
 {
 	struct wakeup_source *ws;
+	int ret;
 
 	ws = wakeup_source_create(name);
-	if (ws)
+	if (ws) {
+		ret = wakeup_source_sysfs_add(dev, ws);
+		if (ret) {
+			wakeup_source_destroy(ws);
+			return NULL;
+		}
 		wakeup_source_add(ws);
-
+	}
 	return ws;
 }
 EXPORT_SYMBOL_GPL(wakeup_source_register);
@@ -215,6 +234,7 @@ void wakeup_source_unregister(struct wakeup_source *ws)
 {
 	if (ws) {
 		wakeup_source_remove(ws);
+		wakeup_source_sysfs_remove(ws);
 		wakeup_source_destroy(ws);
 	}
 }
@@ -258,7 +278,7 @@ int device_wakeup_enable(struct device *dev)
 	if (pm_suspend_target_state != PM_SUSPEND_ON)
 		dev_dbg(dev, "Suspicious %s() during system transition!\n", __func__);
 
-	ws = wakeup_source_register(dev_name(dev));
+	ws = wakeup_source_register(dev, dev_name(dev));
 	if (!ws)
 		return -ENOMEM;
 
diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
new file mode 100644
index 000000000000..220a20ff8918
--- /dev/null
+++ b/drivers/base/power/wakeup_stats.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Wakeup statistics in sysfs
+ *
+ * Copyright (c) 2019 Linux Foundation
+ * Copyright (c) 2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (c) 2019 Google Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/kdev_t.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/timekeeping.h>
+
+#include "power.h"
+
+static struct class *wakeup_class;
+
+#define wakeup_attr(_name)						\
+static ssize_t _name##_show(struct device *dev,				\
+			    struct device_attribute *attr, char *buf)	\
+{									\
+	struct wakeup_source *ws = dev_get_drvdata(dev);		\
+									\
+	return sprintf(buf, "%lu\n", ws->_name);			\
+}									\
+static DEVICE_ATTR_RO(_name)
+
+wakeup_attr(active_count);
+wakeup_attr(event_count);
+wakeup_attr(wakeup_count);
+wakeup_attr(expire_count);
+
+static ssize_t active_time_ms_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	ktime_t active_time =
+		ws->active ? ktime_sub(ktime_get(), ws->last_time) : 0;
+
+	return sprintf(buf, "%lld\n", ktime_to_ms(active_time));
+}
+static DEVICE_ATTR_RO(active_time_ms);
+
+static ssize_t total_time_ms_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	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));
+}
+static DEVICE_ATTR_RO(total_time_ms);
+
+static ssize_t max_time_ms_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	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));
+}
+static DEVICE_ATTR_RO(max_time_ms);
+
+static ssize_t last_change_ms_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%lld\n", ktime_to_ms(ws->last_time));
+}
+static DEVICE_ATTR_RO(last_change_ms);
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", ws->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t prevent_suspend_time_ms_show(struct device *dev,
+					    struct device_attribute *attr,
+					    char *buf)
+{
+	struct wakeup_source *ws = dev_get_drvdata(dev);
+	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));
+}
+static DEVICE_ATTR_RO(prevent_suspend_time_ms);
+
+static struct attribute *wakeup_source_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_active_count.attr,
+	&dev_attr_event_count.attr,
+	&dev_attr_wakeup_count.attr,
+	&dev_attr_expire_count.attr,
+	&dev_attr_active_time_ms.attr,
+	&dev_attr_total_time_ms.attr,
+	&dev_attr_max_time_ms.attr,
+	&dev_attr_last_change_ms.attr,
+	&dev_attr_prevent_suspend_time_ms.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(wakeup_source);
+
+static void device_create_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+static struct device *wakeup_source_device_create(struct device *parent,
+						  struct wakeup_source *ws)
+{
+	struct device *dev = NULL;
+	int retval = -ENODEV;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	device_initialize(dev);
+	dev->devt = MKDEV(0, 0);
+	dev->class = wakeup_class;
+	dev->parent = parent;
+	dev->groups = wakeup_source_groups;
+	dev->release = device_create_release;
+	dev_set_drvdata(dev, ws);
+	device_set_pm_not_required(dev);
+
+	retval = kobject_set_name(&dev->kobj, "wakeup%d", ws->id);
+	if (retval)
+		goto error;
+
+	retval = device_add(dev);
+	if (retval)
+		goto error;
+
+	return dev;
+
+error:
+	put_device(dev);
+	return ERR_PTR(retval);
+}
+
+/**
+ * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
+ * @parent: Device given wakeup source is associated with (or NULL if virtual).
+ * @ws: Wakeup source to be added in sysfs.
+ */
+int wakeup_source_sysfs_add(struct device *parent, struct wakeup_source *ws)
+{
+	struct device *dev;
+
+	dev = wakeup_source_device_create(parent, ws);
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
+	ws->dev = dev;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_sysfs_add);
+
+/**
+ * wakeup_source_sysfs_remove - Remove wakeup_source attributes from sysfs.
+ * @ws: Wakeup source to be removed from sysfs.
+ */
+void wakeup_source_sysfs_remove(struct wakeup_source *ws)
+{
+	device_unregister(ws->dev);
+}
+EXPORT_SYMBOL_GPL(wakeup_source_sysfs_remove);
+
+static int __init wakeup_sources_sysfs_init(void)
+{
+	wakeup_class = class_create(THIS_MODULE, "wakeup");
+
+	return PTR_ERR_OR_ZERO(wakeup_class);
+}
+postcore_initcall(wakeup_sources_sysfs_init);
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index d7f1f5011fac..c4159bcc05d9 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1459,13 +1459,13 @@ static int ep_create_wakeup_source(struct epitem *epi)
 	struct wakeup_source *ws;
 
 	if (!epi->ep->ws) {
-		epi->ep->ws = wakeup_source_register("eventpoll");
+		epi->ep->ws = wakeup_source_register(NULL, "eventpoll");
 		if (!epi->ep->ws)
 			return -ENOMEM;
 	}
 
 	name = epi->ffd.file->f_path.dentry->d_name.name;
-	ws = wakeup_source_register(name);
+	ws = wakeup_source_register(NULL, name);
 
 	if (!ws)
 		return -ENOMEM;
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index c0cad2d8f800..661efa029c96 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -21,6 +21,7 @@ struct wake_irq;
  * struct wakeup_source - Representation of wakeup sources
  *
  * @name: Name of the wakeup source
+ * @id: Wakeup source id
  * @entry: Wakeup source list entry
  * @lock: Wakeup source lock
  * @wakeirq: Optional device specific wakeirq
@@ -35,11 +36,13 @@ struct wake_irq;
  * @relax_count: Number of times the wakeup source was deactivated.
  * @expire_count: Number of times the wakeup source's timeout has expired.
  * @wakeup_count: Number of times the wakeup source might abort suspend.
+ * @dev: Struct device for sysfs statistics about the wakeup source.
  * @active: Status of the wakeup source.
  * @autosleep_enabled: Autosleep is active, so update @prevent_sleep_time.
  */
 struct wakeup_source {
 	const char 		*name;
+	int			id;
 	struct list_head	entry;
 	spinlock_t		lock;
 	struct wake_irq		*wakeirq;
@@ -55,6 +58,7 @@ struct wakeup_source {
 	unsigned long		relax_count;
 	unsigned long		expire_count;
 	unsigned long		wakeup_count;
+	struct device		*dev;
 	bool			active:1;
 	bool			autosleep_enabled:1;
 };
@@ -85,7 +89,8 @@ extern struct wakeup_source *wakeup_source_create(const char *name);
 extern void wakeup_source_destroy(struct wakeup_source *ws);
 extern void wakeup_source_add(struct wakeup_source *ws);
 extern void wakeup_source_remove(struct wakeup_source *ws);
-extern struct wakeup_source *wakeup_source_register(const char *name);
+extern struct wakeup_source *wakeup_source_register(struct device *dev,
+						    const char *name);
 extern void wakeup_source_unregister(struct wakeup_source *ws);
 extern int device_wakeup_enable(struct device *dev);
 extern int device_wakeup_disable(struct device *dev);
@@ -122,7 +127,8 @@ static inline void wakeup_source_add(struct wakeup_source *ws) {}
 
 static inline void wakeup_source_remove(struct wakeup_source *ws) {}
 
-static inline struct wakeup_source *wakeup_source_register(const char *name)
+static inline struct wakeup_source *wakeup_source_register(struct device *dev,
+							   const char *name)
 {
 	return NULL;
 }
diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
index 41e83a779e19..9af5a50d3489 100644
--- a/kernel/power/autosleep.c
+++ b/kernel/power/autosleep.c
@@ -116,7 +116,7 @@ int pm_autosleep_set_state(suspend_state_t state)
 
 int __init pm_autosleep_init(void)
 {
-	autosleep_ws = wakeup_source_register("autosleep");
+	autosleep_ws = wakeup_source_register(NULL, "autosleep");
 	if (!autosleep_ws)
 		return -ENOMEM;
 
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index d1eb7fd98b64..105df4dfc783 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -188,7 +188,7 @@ static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	wl->ws = wakeup_source_register(wl->name);
+	wl->ws = wakeup_source_register(NULL, wl->name);
 	if (!wl->ws) {
 		kfree(wl->name);
 		kfree(wl);
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 57518efc3810..93b382d9701c 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -97,7 +97,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
 	if (!device_may_wakeup(rtc->dev.parent))
 		return -1;
 
-	__ws = wakeup_source_register("alarmtimer");
+	__ws = wakeup_source_register(dev, "alarmtimer");
 
 	spin_lock_irqsave(&rtcdev_lock, flags);
 	if (!rtcdev) {
-- 
2.22.0.770.g0f2c4a37fd-goog

Re: [PATCH v8 0/3] PM / wakeup: Show wakeup sources stats in sysfs

[Rafael J. Wysocki]

On Wednesday, August 7, 2019 3:48:43 AM CEST Tri Vo wrote:
> 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, create a
> 'struct device' to expose wakeup sources statistics in sysfs under
> /sys/class/wakeup/wakeup<ID>/*.
> 
> Patch 1 and 2 do some cleanup to simplify our changes to how wakeup sources are
> created. Patch 3 implements wakeup sources stats in sysfs.
> 
> Tri Vo (3):
>   PM / wakeup: Drop wakeup_source_init(), wakeup_source_prepare()
>   PM / wakeup: Use wakeup_source_register() in wakelock.c
>   PM / wakeup: Show wakeup sources stats in sysfs
> 
>  Documentation/ABI/testing/sysfs-class-wakeup |  76 +++++++
>  drivers/acpi/device_pm.c                     |   3 +-
>  drivers/base/power/Makefile                  |   2 +-
>  drivers/base/power/power.h                   |   9 +
>  drivers/base/power/wakeup.c                  |  59 +++---
>  drivers/base/power/wakeup_stats.c            | 203 +++++++++++++++++++
>  fs/eventpoll.c                               |   4 +-
>  include/linux/pm_wakeup.h                    |  21 +-
>  kernel/power/autosleep.c                     |   2 +-
>  kernel/power/wakelock.c                      |  32 +--
>  kernel/time/alarmtimer.c                     |   2 +-
>  11 files changed, 358 insertions(+), 55 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-wakeup
>  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.
> 
> v3:
> Changes by Greg:
> - Reworked code to use 'struct device' instead of raw kobjects.
> - Updated documentation file.
> - Only link wakeup_stats.o when CONFIG_PM_SLEEP_STATS is enabled.
> Changes by Tri:
> - Reverted changes to kernel/power/wakelock.c. 'struct device' hides kobject
>   operations. So no need to handle lifetimes in wakelock.c
> 
> v4:
> - Added 'Co-developed-by:' and 'Tested-by:' fields to commit message.
> - Moved new documentation to a separate file
>   Documentation/ABI/testing/sysfs-class-wakeup, as per Greg.
> - Fixed copyright header in drivers/base/power/wakeup_stats.c, as per Greg.
> 
> v5:
> - Removed CONFIG_PM_SLEEP_STATS
> - Used PTR_ERR_OR_ZERO instead of if(IS_ERR(...)) + PTR_ERR, reported by
>   kbuild test robot <lkp@intel.com>
> - Stephen reported that a call to device_init_wakeup() and writing 'enabled' to
>   that device's power/wakeup file results in multiple wakeup source being
>   allocated for that device.  Changed device_wakeup_enable() to check if device
>   wakeup was previously enabled.
> Changes by Stephen:
> - Changed stats location from /sys/class/wakeup/<name>/* to
>   /sys/class/wakeup/wakeup<ID>/*, where ID is an IDA-allocated integer. This
>   avoids name collisions in /sys/class/wakeup/ directory.
> - Added a "name" attribute to wakeup sources, and updated documentation.
> - Device registering the wakeup source is now the parent of the wakeup source.
>   Updated wakeup_source_register()'s signature and its callers accordingly.
> 
> v6:
> - Changed stats location to /sys/class/wakeup/ws<ID>/*
> - Replaced ida_simple_get()/ida_simple_remove() with ida_alloc()/ida_free() as
>   the former is deprecated.
> - Reverted changes to device_init_wakeup(). Rafael is preparing a patch to deal
>   with extra wakeup source allocation in a separate patch.
> 
> v7:
> - Removed wakeup_source_init(), wakeup_source_prepare().
> - Removed duplicate wakeup source creation code from  kernel/power/wakelock.
> - Moved ID allocation to wakeup source object creation time.
> - Changed stats location back to /sys/class/wakeup/wakeup<ID>/*
> - Remove wakeup source device's "power" attributes.
> 
> v8:
> - Updated commit message on patch 1 to indicate change of behavior of
>   wakeup_source_create(), as per Stephen.
> - Included headers for used symbols, as per Stephen.
> - Added a function to create wakeup source devices to use
>   device_set_pm_not_required() to skip power management for such devices, as per
>   Stephen.
> 
> --
> 2.22.0.770.g0f2c4a37fd-goog
> 
> 

All three patches applied along with the later fixes from Stephen.

Thanks!