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authorFieah Lim <kw@fieahl.im>2018-09-11 05:47:25 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-09-18 09:32:56 +0200
commit7037b43e0076cce1c07c72540e219fb5db7ea01f (patch)
treefe6ad1caf17aa94e1bec2891da7423ff00581b52 /drivers/cpuidle
parent6a5f95b5a4f4ff29e4071bc5b95f8f3a2aef046b (diff)
downloadlinux-7037b43e0076cce1c07c72540e219fb5db7ea01f.tar.bz2
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: Fieah Lim <kw@fieahl.im> [ rjw: Changelog cleanup, comment format fix ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/cpuidle.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 6df894d65d9e..4a97446f66d8 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -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();
- 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
+ /*
+ * 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;
dev->states_usage[entered_state].time += dev->last_residency;
dev->states_usage[entered_state].usage++;
} else {