Add a new deferrable delayed work init

Add a new deferrable delayed work init.  This can be used to schedule work
that are 'unimportant' when CPU is idle and can be called later, when CPU
eventually comes out of idle.

Use this init in cpufreq ondemand governor.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/cpufreq/cpufreq_ondemand.c

@@ -470,7 +470,7 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
 	dbs_info->enable = 1;
 	ondemand_powersave_bias_init();
 	dbs_info->sample_type = DBS_NORMAL_SAMPLE;
-	INIT_DELAYED_WORK(&dbs_info->work, do_dbs_timer);
+	INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
 	queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work,
 	                      delay);
 }

include/linux/workqueue.h

@@ -121,6 +121,12 @@ struct execute_work {
 		init_timer(&(_work)->timer);			\
 	} while (0)
 
+#define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)			\
+	do {							\
+		INIT_WORK(&(_work)->work, (_func));		\
+		init_timer_deferrable(&(_work)->timer);		\
+	} while (0)
+
 /**
  * work_pending - Find out whether a work item is currently pending
  * @work: The work item in question