Commit 7037b43e authored by Fieah Lim's avatar Fieah Lim Committed by Rafael J. Wysocki
Browse files

cpuidle: enter_state: Don't needlessly calculate diff time 



Currently, ktime_us_delta() is invoked unconditionally to compute the
idle residency of the CPU, but it only makes sense to do that if a
valid idle state has been entered, so move the ktime_us_delta()
invocation after the entered_state >= 0 check.

While at it, merge two comment blocks in there into one and drop
a space between type casting of diff.

This patch has no functional changes.

Signed-off-by: default avatarFieah Lim <kw@fieahl.im>
[ rjw: Changelog cleanup, comment format fix ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6a5f95b5

drivers/cpuidle/cpuidle.c

+8 −8
Original line number Diff line number Diff line
@@ -247,17 +247,17 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, 
	if (!cpuidle_state_is_coupled(drv, index))

		local_irq_enable();



	if (entered_state >= 0) {

		/*

		 * Update cpuidle counters

		 * This can be moved to within driver enter routine,

		 * but that results in multiple copies of same code.

		 */

		diff = ktime_us_delta(time_end, time_start);

		if (diff > INT_MAX)

			diff = INT_MAX;



		dev->last_residency = (int)diff;



	if (entered_state >= 0) {

		/* Update cpuidle counters */

		/* This can be moved to within driver enter routine

		 * but that results in multiple copies of same code.

		 */

		dev->states_usage[entered_state].time += dev->last_residency;

		dev->states_usage[entered_state].usage++;

	} else {