[tip: sched/core] cpufreq: Use vtime aware kcpustat accessors for user time

From: tip-bot2 for Frederic Weisbecker
Date: Thu Nov 21 2019 - 11:48:18 EST


The following commit has been merged into the sched/core branch of tip:

Commit-ID: 5720821ba1d845f0b91a9278137e9005c5f6931d
Gitweb: https://git.kernel.org/tip/5720821ba1d845f0b91a9278137e9005c5f6931d
Author: Frederic Weisbecker <frederic@xxxxxxxxxx>
AuthorDate: Thu, 21 Nov 2019 03:44:28 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 21 Nov 2019 07:33:25 +01:00

cpufreq: Use vtime aware kcpustat accessors for user time

We can now safely read user and guest kcpustat fields on nohz_full CPUs.
Use the appropriate accessors.

Reported-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20191121024430.19938-5-frederic@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 17 ++++++++++-------
drivers/cpufreq/cpufreq_governor.c | 6 +++---
2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 527fd06..ee23eaf 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -113,18 +113,21 @@ EXPORT_SYMBOL_GPL(get_governor_parent_kobj);

static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
{
- u64 idle_time;
+ struct kernel_cpustat kcpustat;
u64 cur_wall_time;
+ u64 idle_time;
u64 busy_time;

cur_wall_time = jiffies64_to_nsecs(get_jiffies_64());

- busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
- busy_time += kcpustat_field(&kcpustat_cpu(cpu), CPUTIME_SYSTEM, cpu);
- busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
- busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
- busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
- busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
+ kcpustat_cpu_fetch(&kcpustat, cpu);
+
+ busy_time = kcpustat.cpustat[CPUTIME_USER];
+ busy_time += kcpustat.cpustat[CPUTIME_SYSTEM];
+ busy_time += kcpustat.cpustat[CPUTIME_IRQ];
+ busy_time += kcpustat.cpustat[CPUTIME_SOFTIRQ];
+ busy_time += kcpustat.cpustat[CPUTIME_STEAL];
+ busy_time += kcpustat.cpustat[CPUTIME_NICE];

idle_time = cur_wall_time - busy_time;
if (wall)
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 4bb054d..f99ae45 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -105,7 +105,7 @@ void gov_update_cpu_data(struct dbs_data *dbs_data)
j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time,
dbs_data->io_is_busy);
if (dbs_data->ignore_nice_load)
- j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+ j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
}
}
}
@@ -149,7 +149,7 @@ unsigned int dbs_update(struct cpufreq_policy *policy)
j_cdbs->prev_cpu_idle = cur_idle_time;

if (ignore_nice) {
- u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+ u64 cur_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);

idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC);
j_cdbs->prev_cpu_nice = cur_nice;
@@ -530,7 +530,7 @@ int cpufreq_dbs_governor_start(struct cpufreq_policy *policy)
j_cdbs->prev_load = 0;

if (ignore_nice)
- j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+ j_cdbs->prev_cpu_nice = kcpustat_field(&kcpustat_cpu(j), CPUTIME_NICE, j);
}

gov->start(policy);