time: Add rq_stats snapshot

Add snapshot of runqueue stats module as of commit <e56fe938419e>
(Merge "uapi: Introduce V4L2_FLAG_CVPMETADATA_SKIP flag").

Added #ifdefery to allow rq_stats to actually be optional.

Change-Id: I3352a472c5b0ad61cc04317a1d6f26549bfcdc04
Signed-off-by: Elliot Berman <eberman@codeaurora.org>

kernel/time/tick-sched.c

@@ -23,6 +23,7 @@
 #include <linux/module.h>
 #include <linux/irq_work.h>
 #include <linux/posix-timers.h>
+#include <linux/rq_stats.h>
 #include <linux/timer.h>
 #include <linux/context_tracking.h>
 #include <linux/mm.h>
@@ -1284,6 +1285,18 @@ void tick_irq_enter(void)
  * High resolution timer specific code
  */
 #ifdef CONFIG_HIGH_RES_TIMERS
+#ifdef CONFIG_QCOM_RUN_QUEUE_STATS
+static void wakeup_user(void)
+{
+	unsigned long jiffy_gap;
+
+	jiffy_gap = jiffies - rq_info.def_timer_last_jiffy;
+	if (jiffy_gap >= rq_info.def_timer_jiffies) {
+		rq_info.def_timer_last_jiffy = jiffies;
+		queue_work(rq_wq, &rq_info.def_timer_work);
+	}
+}
+#endif
 /*
  * We rearm the timer until we get disabled by the idle code.
  * Called with interrupts disabled.
@@ -1301,8 +1314,18 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
 	 * Do not call, when we are not in irq context and have
 	 * no valid regs pointer
 	 */
-	if (regs)
+	if (regs) {
 		tick_sched_handle(ts, regs);
+#ifdef CONFIG_QCOM_RUN_QUEUE_STATS
+		if (rq_info.init == 1 &&
+				tick_do_timer_cpu == smp_processor_id()) {
+			/*
+			 * wakeup user if needed
+			 */
+			wakeup_user();
+		}
+#endif
+	}
 	else
 		ts->next_tick = 0;