[PATCH 6/8] PM: suspend_block: Add suspend_blocker stats

["Arve Hjønnevåg" <arve@android.com>]

Report suspend block stats in /proc/suspend_blockers.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
 include/linux/suspend_block.h |   11 +++
 kernel/power/Kconfig          |    7 ++
 kernel/power/suspend_block.c  |  201 ++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 217 insertions(+), 2 deletions(-)

diff --git a/include/linux/suspend_block.h b/include/linux/suspend_block.h
index 73ac5f7..31225c5 100755
--- a/include/linux/suspend_block.h
+++ b/include/linux/suspend_block.h
@@ -17,6 +17,7 @@
 #define _LINUX_SUSPEND_BLOCK_H
 
 #include <linux/list.h>
+#include <linux/ktime.h>
 
 /* A suspend_blocker prevents the system from entering suspend when active.
  */
@@ -26,6 +27,16 @@ struct suspend_blocker {
 	struct list_head    link;
 	int                 flags;
 	const char         *name;
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	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 2cf4c4d..3de0c5f 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -126,6 +126,13 @@ config SUSPEND_BLOCK
 	  /sys/power/request_state, the requested sleep state will be entered
 	  when no suspend_blockers are active.
 
+config SUSPEND_BLOCK_STAT
+	bool "Suspend block stats"
+	depends on SUSPEND_BLOCK
+	default y
+	---help---
+	  Report suspend block stats in /proc/suspend_blockers
+
 config USER_SUSPEND_BLOCK
 	bool "Userspace suspend blockers"
 	depends on SUSPEND_BLOCK
diff --git a/kernel/power/suspend_block.c b/kernel/power/suspend_block.c
index 697f52a..78d5880 100644
--- a/kernel/power/suspend_block.c
+++ b/kernel/power/suspend_block.c
@@ -18,6 +18,9 @@
 #include <linux/suspend.h>
 #include <linux/suspend_block.h>
 #include <linux/sysdev.h>
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+#include <linux/proc_fs.h>
+#endif
 #include "power.h"
 
 enum {
@@ -32,6 +35,7 @@ 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);
@@ -42,6 +46,165 @@ struct workqueue_struct *suspend_work_queue;
 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;
+
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+static struct suspend_blocker deleted_suspend_blockers;
+static ktime_t last_sleep_time_update;
+static bool wait_for_wakeup;
+
+static int print_blocker_stat(char *buf, 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 sprintf(buf, "\"%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_read_proc(char *page, char **start, off_t off,
+			       int count, int *eof, void *data)
+{
+	unsigned long irqflags;
+	struct suspend_blocker *blocker;
+	int len = 0;
+	char *p = page;
+
+	spin_lock_irqsave(&list_lock, irqflags);
+
+	p += sprintf(p, "name\tcount\twake_count\tactive_since"
+		     "\ttotal_time\tsleep_time\tmax_time\tlast_change\n");
+	list_for_each_entry(blocker, &inactive_blockers, link) {
+		p += print_blocker_stat(p, blocker);
+	}
+	list_for_each_entry(blocker, &active_blockers, link)
+		p += print_blocker_stat(p, blocker);
+	spin_unlock_irqrestore(&list_lock, irqflags);
+
+	*start = page + off;
+
+	len = p - page;
+	if (len > off)
+		len -= off;
+	else
+		len = 0;
+
+	return len < count ? len  : count;
+}
+
+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;
+}
+
+#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) {}
+
+#endif
+
 
 static void print_active_blockers_locked(void)
 {
@@ -65,7 +228,6 @@ static void suspend_worker(struct work_struct *work)
 
 	enable_suspend_blockers = 1;
 
-retry:
 	if (suspend_is_blocked()) {
 		if (debug_mask & DEBUG_SUSPEND)
 			pr_info("suspend: abort suspend\n");
@@ -89,7 +251,8 @@ retry:
 	if (current_event_num == entry_event_num) {
 		if (debug_mask & DEBUG_SUSPEND)
 			pr_info("suspend: pm_suspend returned with no event\n");
-		goto retry;
+		suspend_block(&unknown_wakeup);
+		suspend_unblock(&unknown_wakeup);
 	}
 abort:
 	enable_suspend_blockers = 0;
@@ -99,6 +262,9 @@ static DECLARE_WORK(suspend_work, suspend_worker);
 static int suspend_block_suspend(struct sys_device *dev, pm_message_t state)
 {
 	int ret = suspend_is_blocked() ? -EAGAIN : 0;
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	wait_for_wakeup = true;
+#endif
 	if (debug_mask & DEBUG_SUSPEND)
 		pr_info("suspend_block_suspend return %d\n", ret);
 	return ret;
@@ -133,6 +299,7 @@ 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);
 }
@@ -148,6 +315,7 @@ void suspend_blocker_destroy(struct suspend_blocker *blocker)
 	if (debug_mask & DEBUG_SUSPEND_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))
@@ -167,6 +335,7 @@ void suspend_block(struct suspend_blocker *blocker)
 	spin_lock_irqsave(&list_lock, irqflags);
 	BUG_ON(!(blocker->flags & SB_INITIALIZED));
 
+	suspend_block_stat_locked(blocker);
 	blocker->flags |= SB_ACTIVE;
 	list_del(&blocker->link);
 	if (debug_mask & DEBUG_SUSPEND_BLOCKER)
@@ -174,6 +343,10 @@ void suspend_block(struct suspend_blocker *blocker)
 	list_add(&blocker->link, &active_blockers);
 
 	current_event_num++;
+	if (blocker == &main_suspend_blocker)
+		update_sleep_wait_stats_locked(true);
+	else if (!is_blocking_suspend(&main_suspend_blocker))
+		update_sleep_wait_stats_locked(false);
 	spin_unlock_irqrestore(&list_lock, irqflags);
 }
 EXPORT_SYMBOL(suspend_block);
@@ -190,6 +363,8 @@ void suspend_unblock(struct suspend_blocker *blocker)
 
 	spin_lock_irqsave(&list_lock, irqflags);
 
+	suspend_unblock_stat_locked(blocker);
+
 	if (debug_mask & DEBUG_SUSPEND_BLOCKER)
 		pr_info("suspend_unblock: %s\n", blocker->name);
 	list_del(&blocker->link);
@@ -201,6 +376,7 @@ 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);
 }
@@ -245,8 +421,13 @@ static int __init suspend_block_init(void)
 {
 	int ret;
 
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	suspend_blocker_init(&deleted_suspend_blockers,
+				"deleted_suspend_blockers");
+#endif
 	suspend_blocker_init(&main_suspend_blocker, "main");
 	suspend_block(&main_suspend_blocker);
+	suspend_blocker_init(&unknown_wakeup, "unknown_wakeups");
 
 	ret = sysdev_class_register(&suspend_block_sysclass);
 	if (ret) {
@@ -265,6 +446,11 @@ static int __init suspend_block_init(void)
 		goto err_suspend_work_queue;
 	}
 
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	create_proc_read_entry("suspend_blockers", S_IRUGO, NULL,
+				suspend_blocker_stats_read_proc, NULL);
+#endif
+
 	return 0;
 
 err_suspend_work_queue:
@@ -272,16 +458,27 @@ err_suspend_work_queue:
 err_sysdev_register:
 	sysdev_class_unregister(&suspend_block_sysclass);
 err_sysdev_class_register:
+	suspend_blocker_destroy(&unknown_wakeup);
 	suspend_blocker_destroy(&main_suspend_blocker);
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	suspend_blocker_destroy(&deleted_suspend_blockers);
+#endif
 	return ret;
 }
 
 static void  __exit suspend_block_exit(void)
 {
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	remove_proc_entry("suspend_blockers", NULL);
+#endif
 	destroy_workqueue(suspend_work_queue);
 	sysdev_unregister(&suspend_block_sysdev);
 	sysdev_class_unregister(&suspend_block_sysclass);
+	suspend_blocker_destroy(&unknown_wakeup);
 	suspend_blocker_destroy(&main_suspend_blocker);
+#ifdef CONFIG_SUSPEND_BLOCK_STAT
+	suspend_blocker_destroy(&deleted_suspend_blockers);
+#endif
 }
 
 core_initcall(suspend_block_init);
-- 
1.6.1

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