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Commit 6ce12a97 authored by SungEun Kim's avatar SungEun Kim Committed by Rafael J. Wysocki
Browse files

PM / autosleep: Use workqueue for user space wakeup sources garbage collector 



The synchronous synchronize_rcu() in wakeup_source_remove() makes
user process which writes to /sys/kernel/wake_unlock blocked sometimes.

For example, when android eventhub tries to release a wakelock, this
blocking process can occur, and eventhub can't get input events
for a while.

Using a work item instead of direct function call at pm_wake_unlock()
can prevent this unnecessary delay from happening.

Signed-off-by: default avatarSungEun Kim <cleaneye.kim@lge.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent bc0195aa

kernel/power/wakelock.c

+15 −3
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/list.h>

#include <linux/rbtree.h>

#include <linux/slab.h>

#include <linux/workqueue.h>



#include "power.h"
@@ -83,7 +84,9 @@ static inline void decrement_wakelocks_number(void) {} 
#define WL_GC_COUNT_MAX	100

#define WL_GC_TIME_SEC	300



static void __wakelocks_gc(struct work_struct *work);

static LIST_HEAD(wakelocks_lru_list);

static DECLARE_WORK(wakelock_work, __wakelocks_gc);

static unsigned int wakelocks_gc_count;



static inline void wakelocks_lru_add(struct wakelock *wl)
@@ -96,13 +99,12 @@ static inline void wakelocks_lru_most_recent(struct wakelock *wl) 
	list_move(&wl->lru, &wakelocks_lru_list);

}



static void wakelocks_gc(void)

static void __wakelocks_gc(struct work_struct *work)

{

	struct wakelock *wl, *aux;

	ktime_t now;



	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)

		return;

	mutex_lock(&wakelocks_lock);



	now = ktime_get();

	list_for_each_entry_safe_reverse(wl, aux, &wakelocks_lru_list, lru) {
@@ -127,6 +129,16 @@ static void wakelocks_gc(void) 
		}

	}

	wakelocks_gc_count = 0;



	mutex_unlock(&wakelocks_lock);

}



static void wakelocks_gc(void)

{

	if (++wakelocks_gc_count <= WL_GC_COUNT_MAX)

		return;



	schedule_work(&wakelock_work);

}

#else /* !CONFIG_PM_WAKELOCKS_GC */

static inline void wakelocks_lru_add(struct wakelock *wl) {}