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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 15 Jul 2019 23:48:27 +0200
Message-ID: <CAJZ5v0gEzZkbeLFtW5yadwxBryvL3vWcUoQTkUy3VkxiTV+UrA@mail.gmail.com>
Subject: Re: [PATCH v4] PM / wakeup: show wakeup sources stats in sysfs
To:     Tri Vo <trong@android.com>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Hridya Valsaraju <hridya@google.com>, sspatil@google.com,
        kaleshsingh@google.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        "Cc: Android Kernel" <kernel-team@android.com>
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Sender: linux-kernel-owner@vger.kernel.org
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On Mon, Jul 15, 2019 at 11:44 PM Tri Vo <trong@android.com> 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/<name>/.
>
> Introduce CONFIG_PM_SLEEP_STATS that enables/disables showing wakeup
> source statistics in sysfs.

I'm not sure if this is really needed, but I'll let Greg decide.

Apart from this

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

>
> Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 |  70 +++++++++
>  drivers/base/power/Makefile                  |   1 +
>  drivers/base/power/wakeup.c                  |  12 +-
>  drivers/base/power/wakeup_stats.c            | 149 +++++++++++++++++++
>  include/linux/pm_wakeup.h                    |  19 +++
>  kernel/power/Kconfig                         |  10 ++
>  kernel/power/wakelock.c                      |  10 ++
>  7 files changed, 269 insertions(+), 2 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.
>
> diff --git a/Documentation/ABI/testing/sysfs-class-wakeup b/Documentation/ABI/testing/sysfs-class-wakeup
> new file mode 100644
> index 000000000000..30fb23eb9112
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-wakeup
> @@ -0,0 +1,70 @@
> +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/.../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/base/power/Makefile b/drivers/base/power/Makefile
> index e1bb691cf8f1..1963f53d9982 100644
> --- a/drivers/base/power/Makefile
> +++ b/drivers/base/power/Makefile
> @@ -1,6 +1,7 @@
>  # 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-$(CONFIG_PM_SLEEP_STATS)   += wakeup_stats.o
>  obj-$(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/wakeup.c b/drivers/base/power/wakeup.c
> index 5b2b6a05a4f3..fd48e78c06b9 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -205,11 +205,18 @@ 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) {
> +                       kfree_const(ws->name);
> +                       kfree(ws);
> +                       return NULL;
> +               }
>                 wakeup_source_add(ws);
> -
> +       }
>         return ws;
>  }
>  EXPORT_SYMBOL_GPL(wakeup_source_register);
> @@ -222,6 +229,7 @@ void wakeup_source_unregister(struct wakeup_source *ws)
>  {
>         if (ws) {
>                 wakeup_source_remove(ws);
> +               wakeup_source_sysfs_remove(ws);
>                 wakeup_source_destroy(ws);
>         }
>  }
> diff --git a/drivers/base/power/wakeup_stats.c b/drivers/base/power/wakeup_stats.c
> new file mode 100644
> index 000000000000..45e15856105b
> --- /dev/null
> +++ b/drivers/base/power/wakeup_stats.c
> @@ -0,0 +1,149 @@
> +// 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/slab.h>
> +#include <linux/kdev_t.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 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_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);
> +
> +/**
> + * wakeup_source_sysfs_add - Add wakeup_source attributes to sysfs.
> + * @ws: Wakeup source to be added in sysfs.
> + */
> +int wakeup_source_sysfs_add(struct wakeup_source *ws)
> +{
> +       struct device *dev;
> +
> +       dev = device_create_with_groups(wakeup_class, NULL, MKDEV(0, 0), ws,
> +                                       wakeup_source_groups, "%s", ws->name);
> +       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");
> +       if (IS_ERR(wakeup_class))
> +               return PTR_ERR(wakeup_class);
> +
> +       return 0;
> +}
> +
> +postcore_initcall(wakeup_sources_sysfs_init);
> diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
> index ce57771fab9b..734141869c17 100644
> --- a/include/linux/pm_wakeup.h
> +++ b/include/linux/pm_wakeup.h
> @@ -35,6 +35,7 @@ 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.
>   * @has_timeout: The wakeup source has been activated with a timeout.
>   */
> @@ -55,6 +56,7 @@ 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;
>  };
> @@ -181,6 +183,23 @@ 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 */
> +int wakeup_source_sysfs_add(struct wakeup_source *ws);
> +void wakeup_source_sysfs_remove(struct wakeup_source *ws);
> +
> +#else /* !CONFIG_PM_SLEEP_STATS */
> +
> +static inline int wakeup_source_sysfs_add(struct wakeup_source *ws)
> +{
> +       return 0;
> +}
> +static inline void wakeup_source_sysfs_remove(struct wakeup_source *ws)
> +{ }
> +
> +#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..604e1f087f14 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-class-wakeup>.
> +
> +         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..32726da3d6e6 100644
> --- a/kernel/power/wakelock.c
> +++ b/kernel/power/wakelock.c
> @@ -122,6 +122,7 @@ static void __wakelocks_gc(struct work_struct *work)
>
>                 if (!active) {
>                         wakeup_source_remove(&wl->ws);
> +                       wakeup_source_sysfs_remove(&wl->ws);
>                         rb_erase(&wl->node, &wakelocks_tree);
>                         list_del(&wl->lru);
>                         kfree(wl->name);
> @@ -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;
> @@ -189,6 +191,14 @@ static struct wakelock *wakelock_lookup_add(const char *name, size_t len,
>         }
>         wl->ws.name = wl->name;
>         wl->ws.last_time = ktime_get();
> +
> +       ret = wakeup_source_sysfs_add(&wl->ws);
> +       if (ret) {
> +               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);
> --
> 2.22.0.510.g264f2c817a-goog
>