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Subject[PATCH 5/8] PM: suspend_block: Add suspend_blocker stats
Date
Report suspend block stats in /sys/kernel/debug/suspend_blockers.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
include/linux/suspend_blocker.h | 21 ++++-
kernel/power/Kconfig | 7 ++
kernel/power/power.h | 5 +
kernel/power/suspend.c | 4 +-
kernel/power/suspend_blocker.c | 190 +++++++++++++++++++++++++++++++++++++--
5 files changed, 218 insertions(+), 9 deletions(-)

diff --git a/include/linux/suspend_blocker.h b/include/linux/suspend_blocker.h
index f9928cc..c80764c 100755
--- a/include/linux/suspend_blocker.h
+++ b/include/linux/suspend_blocker.h
@@ -17,12 +17,21 @@
#define _LINUX_SUSPEND_BLOCKER_H

#include <linux/list.h>
+#include <linux/ktime.h>

/**
* struct suspend_blocker - the basic suspend_blocker structure
* @link: List entry for active or inactive list.
- * @flags: Tracks initialized and active state.
+ * @flags: Tracks initialized, active and stats state.
* @name: Name used for debugging.
+ * @count: Number of times this blocker has been deacivated
+ * @wakeup_count: Number of times this blocker was the first to block suspend
+ * after resume.
+ * @total_time: Total time this suspend blocker has prevented suspend.
+ * @prevent_suspend_time: Time this suspend blocker has prevented suspend while
+ * user-space requested suspend.
+ * @max_time: Max time this suspend blocker has been continuously active
+ * @last_time: Monotonic clock when the active state last changed.
*
* When a suspend_blocker is active it prevents the system from entering
* opportunistic suspend.
@@ -35,6 +44,16 @@ struct suspend_blocker {
struct list_head link;
int flags;
const char *name;
+#ifdef CONFIG_SUSPEND_BLOCKER_STATS
+ struct {
+ int count;
+ int wakeup_count;
+ ktime_t total_time;
+ ktime_t prevent_suspend_time;
+ ktime_t max_time;
+ ktime_t last_time;
+ } stat;
+#endif
#endif
};

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index fe5a2f2..4bcba07 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -146,6 +146,13 @@ config OPPORTUNISTIC_SUSPEND
determines the sleep state the system will be put into when there are
no active suspend blockers.

+config SUSPEND_BLOCKER_STATS
+ bool "Suspend block stats"
+ depends on OPPORTUNISTIC_SUSPEND
+ default y
+ ---help---
+ Report suspend block stats in /sys/kernel/debug/suspend_blockers
+
config USER_SUSPEND_BLOCKERS
bool "Userspace suspend blockers"
depends on OPPORTUNISTIC_SUSPEND
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 67d10fd..897c116 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -245,3 +245,8 @@ extern void __init suspend_block_init(void);
#else
static inline void suspend_block_init(void) {}
#endif
+#ifdef CONFIG_SUSPEND_BLOCKER_STATS
+void about_to_enter_suspend(void);
+#else
+static inline void about_to_enter_suspend(void) {}
+#endif
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index dc42006..6d327ea 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -159,8 +159,10 @@ static int suspend_enter(suspend_state_t state)

error = sysdev_suspend(PMSG_SUSPEND);
if (!error) {
- if (!suspend_is_blocked() && !suspend_test(TEST_CORE))
+ if (!suspend_is_blocked() && !suspend_test(TEST_CORE)) {
+ about_to_enter_suspend();
error = suspend_ops->enter(state);
+ }
sysdev_resume();
}

diff --git a/kernel/power/suspend_blocker.c b/kernel/power/suspend_blocker.c
index ced4993..77920e6 100644
--- a/kernel/power/suspend_blocker.c
+++ b/kernel/power/suspend_blocker.c
@@ -34,6 +34,7 @@ module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);

#define SB_INITIALIZED (1U << 8)
#define SB_ACTIVE (1U << 9)
+#define SB_PREVENTING_SUSPEND (1U << 10)

static DEFINE_SPINLOCK(list_lock);
static DEFINE_SPINLOCK(state_lock);
@@ -43,6 +44,7 @@ static int current_event_num;
struct suspend_blocker main_suspend_blocker;
static suspend_state_t requested_suspend_state = PM_SUSPEND_MEM;
static bool enable_suspend_blockers;
+static struct suspend_blocker unknown_wakeup;
static struct dentry *suspend_blocker_stats_dentry;

#define pr_info_time(fmt, args...) \
@@ -57,6 +59,153 @@ static struct dentry *suspend_blocker_stats_dentry;
tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec); \
} while (0);

+#ifdef CONFIG_SUSPEND_BLOCKER_STATS
+static struct suspend_blocker deleted_suspend_blockers;
+static ktime_t last_sleep_time_update;
+static bool wait_for_wakeup;
+
+static int print_blocker_stat(struct seq_file *m,
+ struct suspend_blocker *blocker)
+{
+ int lock_count = blocker->stat.count;
+ ktime_t active_time = ktime_set(0, 0);
+ ktime_t total_time = blocker->stat.total_time;
+ ktime_t max_time = blocker->stat.max_time;
+ ktime_t prevent_suspend_time = blocker->stat.prevent_suspend_time;
+ if (blocker->flags & SB_ACTIVE) {
+ ktime_t now, add_time;
+ now = ktime_get();
+ add_time = ktime_sub(now, blocker->stat.last_time);
+ lock_count++;
+ active_time = add_time;
+ total_time = ktime_add(total_time, add_time);
+ if (blocker->flags & SB_PREVENTING_SUSPEND)
+ prevent_suspend_time = ktime_add(prevent_suspend_time,
+ ktime_sub(now, last_sleep_time_update));
+ if (add_time.tv64 > max_time.tv64)
+ max_time = add_time;
+ }
+
+ return seq_printf(m, "\"%s\"\t%d\t%d\t%lld\t%lld\t%lld\t%lld\t%lld\n",
+ blocker->name, lock_count, blocker->stat.wakeup_count,
+ ktime_to_ns(active_time), ktime_to_ns(total_time),
+ ktime_to_ns(prevent_suspend_time), ktime_to_ns(max_time),
+ ktime_to_ns(blocker->stat.last_time));
+}
+
+
+static int suspend_blocker_stats_show(struct seq_file *m, void *unused)
+{
+ unsigned long irqflags;
+ struct suspend_blocker *blocker;
+
+ seq_puts(m, "name\tcount\twake_count\tactive_since"
+ "\ttotal_time\tsleep_time\tmax_time\tlast_change\n");
+ spin_lock_irqsave(&list_lock, irqflags);
+ list_for_each_entry(blocker, &inactive_blockers, link)
+ print_blocker_stat(m, blocker);
+ list_for_each_entry(blocker, &active_blockers, link)
+ print_blocker_stat(m, blocker);
+ spin_unlock_irqrestore(&list_lock, irqflags);
+ return 0;
+}
+
+static void suspend_blocker_stat_init_locked(struct suspend_blocker *blocker)
+{
+ blocker->stat.count = 0;
+ blocker->stat.wakeup_count = 0;
+ blocker->stat.total_time = ktime_set(0, 0);
+ blocker->stat.prevent_suspend_time = ktime_set(0, 0);
+ blocker->stat.max_time = ktime_set(0, 0);
+ blocker->stat.last_time = ktime_set(0, 0);
+}
+
+static void suspend_blocker_stat_destroy_locked(struct suspend_blocker *bl)
+{
+ if (!bl->stat.count)
+ return;
+ deleted_suspend_blockers.stat.count += bl->stat.count;
+ deleted_suspend_blockers.stat.total_time = ktime_add(
+ deleted_suspend_blockers.stat.total_time, bl->stat.total_time);
+ deleted_suspend_blockers.stat.prevent_suspend_time = ktime_add(
+ deleted_suspend_blockers.stat.prevent_suspend_time,
+ bl->stat.prevent_suspend_time);
+ deleted_suspend_blockers.stat.max_time = ktime_add(
+ deleted_suspend_blockers.stat.max_time, bl->stat.max_time);
+}
+
+static void suspend_unblock_stat_locked(struct suspend_blocker *blocker)
+{
+ ktime_t duration;
+ ktime_t now;
+ if (!(blocker->flags & SB_ACTIVE))
+ return;
+ now = ktime_get();
+ blocker->stat.count++;
+ duration = ktime_sub(now, blocker->stat.last_time);
+ blocker->stat.total_time =
+ ktime_add(blocker->stat.total_time, duration);
+ if (ktime_to_ns(duration) > ktime_to_ns(blocker->stat.max_time))
+ blocker->stat.max_time = duration;
+ blocker->stat.last_time = ktime_get();
+ if (blocker->flags & SB_PREVENTING_SUSPEND) {
+ duration = ktime_sub(now, last_sleep_time_update);
+ blocker->stat.prevent_suspend_time = ktime_add(
+ blocker->stat.prevent_suspend_time, duration);
+ blocker->flags &= ~SB_PREVENTING_SUSPEND;
+ }
+}
+
+static void suspend_block_stat_locked(struct suspend_blocker *blocker)
+{
+ if (wait_for_wakeup) {
+ if (debug_mask & DEBUG_WAKEUP)
+ pr_info("wakeup suspend blocker: %s\n", blocker->name);
+ wait_for_wakeup = false;
+ blocker->stat.wakeup_count++;
+ }
+ if (!(blocker->flags & SB_ACTIVE))
+ blocker->stat.last_time = ktime_get();
+}
+
+static void update_sleep_wait_stats_locked(bool done)
+{
+ struct suspend_blocker *blocker;
+ ktime_t now, elapsed, add;
+
+ now = ktime_get();
+ elapsed = ktime_sub(now, last_sleep_time_update);
+ list_for_each_entry(blocker, &active_blockers, link) {
+ if (blocker->flags & SB_PREVENTING_SUSPEND) {
+ add = elapsed;
+ blocker->stat.prevent_suspend_time = ktime_add(
+ blocker->stat.prevent_suspend_time, add);
+ }
+ if (done)
+ blocker->flags &= ~SB_PREVENTING_SUSPEND;
+ else
+ blocker->flags |= SB_PREVENTING_SUSPEND;
+ }
+ last_sleep_time_update = now;
+}
+
+void about_to_enter_suspend(void)
+{
+ wait_for_wakeup = true;
+}
+
+#else
+
+static inline void suspend_blocker_stat_init_locked(
+ struct suspend_blocker *blocker) {}
+static inline void suspend_blocker_stat_destroy_locked(
+ struct suspend_blocker *blocker) {}
+static inline void suspend_block_stat_locked(
+ struct suspend_blocker *blocker) {}
+static inline void suspend_unblock_stat_locked(
+ struct suspend_blocker *blocker) {}
+static inline void update_sleep_wait_stats_locked(bool done) {}
+
static int suspend_blocker_stats_show(struct seq_file *m, void *unused)
{
unsigned long irqflags;
@@ -72,6 +221,8 @@ static int suspend_blocker_stats_show(struct seq_file *m, void *unused)
return 0;
}

+#endif
+
static void print_active_blockers_locked(void)
{
struct suspend_blocker *blocker;
@@ -102,20 +253,31 @@ static void suspend_worker(struct work_struct *work)
int entry_event_num;

enable_suspend_blockers = true;
- while (!suspend_is_blocked()) {
- entry_event_num = current_event_num;

+ if (suspend_is_blocked()) {
if (debug_mask & DEBUG_SUSPEND)
- pr_info("suspend: enter suspend\n");
+ pr_info("suspend: abort suspend\n");
+ goto abort;
+ }
+
+ entry_event_num = current_event_num;

- ret = pm_suspend(requested_suspend_state);
+ if (debug_mask & DEBUG_SUSPEND)
+ pr_info("suspend: enter suspend\n");

- if (debug_mask & DEBUG_EXIT_SUSPEND)
- pr_info_time("suspend: exit suspend, ret = %d ", ret);
+ ret = pm_suspend(requested_suspend_state);

- if (current_event_num == entry_event_num)
+ if (debug_mask & DEBUG_EXIT_SUSPEND)
+ pr_info_time("suspend: exit suspend, ret = %d ", ret);
+
+ if (current_event_num == entry_event_num) {
+ if (debug_mask & DEBUG_SUSPEND)
pr_info("suspend: pm_suspend returned with no event\n");
+
+ suspend_block(&unknown_wakeup);
+ suspend_unblock(&unknown_wakeup);
}
+abort:
enable_suspend_blockers = false;
}
static DECLARE_WORK(suspend_work, suspend_worker);
@@ -142,6 +304,7 @@ void suspend_blocker_init(struct suspend_blocker *blocker, const char *name)
INIT_LIST_HEAD(&blocker->link);

spin_lock_irqsave(&list_lock, irqflags);
+ suspend_blocker_stat_init_locked(blocker);
list_add(&blocker->link, &inactive_blockers);
spin_unlock_irqrestore(&list_lock, irqflags);
}
@@ -161,6 +324,7 @@ void suspend_blocker_destroy(struct suspend_blocker *blocker)
pr_info("suspend_blocker_destroy name=%s\n", blocker->name);

spin_lock_irqsave(&list_lock, irqflags);
+ suspend_blocker_stat_destroy_locked(blocker);
blocker->flags &= ~SB_INITIALIZED;
list_del(&blocker->link);
if ((blocker->flags & SB_ACTIVE) && list_empty(&active_blockers))
@@ -187,9 +351,14 @@ void suspend_block(struct suspend_blocker *blocker)
if (debug_mask & DEBUG_SUSPEND_BLOCKER)
pr_info("suspend_block: %s\n", blocker->name);

+ suspend_block_stat_locked(blocker);
blocker->flags |= SB_ACTIVE;
list_move(&blocker->link, &active_blockers);
current_event_num++;
+ if (blocker == &main_suspend_blocker)
+ update_sleep_wait_stats_locked(true);
+ else if (!suspend_blocker_is_active(&main_suspend_blocker))
+ update_sleep_wait_stats_locked(false);

spin_unlock_irqrestore(&list_lock, irqflags);
}
@@ -215,6 +384,7 @@ void suspend_unblock(struct suspend_blocker *blocker)
if (debug_mask & DEBUG_SUSPEND_BLOCKER)
pr_info("suspend_unblock: %s\n", blocker->name);

+ suspend_unblock_stat_locked(blocker);
list_move(&blocker->link, &inactive_blockers);

if ((blocker->flags & SB_ACTIVE) && list_empty(&active_blockers))
@@ -223,6 +393,7 @@ void suspend_unblock(struct suspend_blocker *blocker)
if (blocker == &main_suspend_blocker) {
if (debug_mask & DEBUG_SUSPEND)
print_active_blockers_locked();
+ update_sleep_wait_stats_locked(false);
}
spin_unlock_irqrestore(&list_lock, irqflags);
}
@@ -288,6 +459,11 @@ void __init suspend_block_init(void)
{
suspend_blocker_init(&main_suspend_blocker, "main");
suspend_block(&main_suspend_blocker);
+ suspend_blocker_init(&unknown_wakeup, "unknown_wakeups");
+#ifdef CONFIG_SUSPEND_BLOCKER_STATS
+ suspend_blocker_init(&deleted_suspend_blockers,
+ "deleted_suspend_blockers");
+#endif
}

static int __init suspend_block_postcore_init(void)
--
1.6.5.1
--
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