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authorMinsung Kim <ms925.kim@samsung.com>2013-04-23 22:32:01 +0900
committerArve Hjønnevåg <arve@android.com>2013-07-01 14:16:27 -0700
commit3ab74abdc30faaaa49eae6ae233769b092ec3378 (patch)
tree3c5a641557d0752e89759ee40cf9fc6d2b738cea /drivers/cpufreq
parentd06bc7e5b3a3968721e0a34ce4a515cf5fa873e3 (diff)
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>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq_interactive.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index b4d12b266c6..7303f50a118 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -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;