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Message-Id: <1445967059-6897-49-git-send-email-czoborbalint@gmail.com> Date: Tue, 27 Oct 2015 18:30:37 +0100 From: Bálint Czobor <czoborbalint@...il.com> To: "Rafael J. Wysocki" <rjw@...ysocki.net>, Viresh Kumar <viresh.kumar@...aro.org> Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, Minsung Kim <ms925.kim@...sung.com>, Bálint Czobor <czoborbalint@...il.com> Subject: [PATCH 49/70] cpufreq: interactive: avoid underflow on active time calculation From: Minsung Kim <ms925.kim@...sung.com> 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@...sung.com> Signed-off-by: Bálint Czobor <czoborbalint@...il.com> --- drivers/cpufreq/cpufreq_interactive.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c index b4d12b2..7303f50 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; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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