uksm: use deferrable timer

1 files changed, 24 insertions, 4 deletions

diff --git a/mm/uksm.c b/mm/uksm.c
index 85ce60edf..bf6eda378 100644
--- a/mm/uksm.c
+++ b/mm/uksm.c
@@ -4586,14 +4586,32 @@ static int ksmd_should_run(void)
 	return uksm_run & UKSM_RUN_MERGE;
 }
 
+static void process_timeout(unsigned long data)
+{
+	wake_up_process((struct task_struct *)data);
+}
+
 static int uksm_scan_thread(void *nothing)
 {
-	long timeout = 60 * HZ;
+	long timeout = 120 * HZ, expire;
+	struct timer_list timer;
+
 	set_freezable();
 	set_user_nice(current, 15);
 
+	setup_deferrable_timer_on_stack(&timer, process_timeout,
+		(unsigned long)current);
+
 	while (!kthread_should_stop()) {
-		timeout = schedule_timeout_interruptible(timeout);
+		__set_current_state(TASK_INTERRUPTIBLE);
+		expire = jiffies + timeout;
+		mod_timer(&timer, expire);
+		schedule();
+		del_singleshot_timer_sync(&timer);
+
+		timeout = expire - jiffies;
+		if (timeout < 0)
+			timeout = 0;
 
 		if (unlikely(try_to_freeze()))
 			timeout = 5 * HZ;
@@ -4609,15 +4627,17 @@ static int uksm_scan_thread(void *nothing)
 		if (likely(ksmd_should_run())) {
 			uksm_do_scan();
 			mutex_unlock(&uksm_thread_mutex);
-			timeout = uksm_sleep_jiffies - jiffies % uksm_sleep_jiffies;
 			uksm_sleep_times++;
 		} else {
 			mutex_unlock(&uksm_thread_mutex);
 			wait_event_freezable(uksm_thread_wait,
 				ksmd_should_run() || kthread_should_stop());
-			timeout = uksm_sleep_jiffies;
 		}
+		timeout = uksm_sleep_jiffies;
 	}
+
+	destroy_timer_on_stack(&timer);
+
 	return 0;
 }