cpufreq: interactive: avoid underflow on active time calculation

Check for idle time delta less than elapsed time delta, avoid
underflow computing active time.

Change-Id: I3e4c6ef1ad794eec49ed379c0c50fa727fd6ad28
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
This commit is contained in:
Minsung Kim 2013-04-23 22:32:01 +09:00 committed by John Stultz
parent aedd63a502
commit 83720c33a9

View file

@ -325,7 +325,12 @@ static u64 update_load(int cpu)
now_idle = get_cpu_idle_time(cpu, &now);
delta_idle = (unsigned int)(now_idle - pcpu->time_in_idle);
delta_time = (unsigned int)(now - pcpu->time_in_idle_timestamp);
active_time = delta_time - delta_idle;
if (delta_time <= delta_idle)
active_time = 0;
else
active_time = delta_time - delta_idle;
pcpu->cputime_speedadj += active_time * pcpu->policy->cur;
pcpu->time_in_idle = now_idle;