[PATCH 3/6] procfs: Use all-in-one vtime aware kcpustat accessor

[Frederic Weisbecker <frederic@kernel.org>]

Now that we can read also user and guest time safely under vtime, use
the relevant accessor to fix frozen kcpustat values on nohz_full CPUs.

Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rik van Riel <riel@surriel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Ingo Molnar <mingo@kernel.org>
---
 fs/proc/stat.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 5c6bd0ae3802..b2ee5418dece 100644
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -120,18 +120,21 @@ static int show_stat(struct seq_file *p, void *v)
 	getboottime64(&boottime);
 
 	for_each_possible_cpu(i) {
+		u64 cpu_user, cpu_nice, cpu_sys, cpu_guest, cpu_guest_nice;
 		struct kernel_cpustat *kcs = &kcpustat_cpu(i);
 
-		user += kcs->cpustat[CPUTIME_USER];
-		nice += kcs->cpustat[CPUTIME_NICE];
-		system += kcpustat_field(kcs, CPUTIME_SYSTEM, i);
+		kcpustat_cputime(kcs, i, &cpu_user, &cpu_nice,
+				 &cpu_sys, &cpu_guest, &cpu_guest_nice);
+		user += cpu_user;
+		nice += cpu_nice;
+		system += cpu_sys;
 		idle += get_idle_time(kcs, i);
 		iowait += get_iowait_time(kcs, i);
 		irq += kcs->cpustat[CPUTIME_IRQ];
 		softirq += kcs->cpustat[CPUTIME_SOFTIRQ];
 		steal += kcs->cpustat[CPUTIME_STEAL];
-		guest += kcs->cpustat[CPUTIME_GUEST];
-		guest_nice += kcs->cpustat[CPUTIME_GUEST_NICE];
+		guest += cpu_guest;
+		guest_nice += guest_nice;
 		sum += kstat_cpu_irqs_sum(i);
 		sum += arch_irq_stat_cpu(i);
 
@@ -159,17 +162,14 @@ static int show_stat(struct seq_file *p, void *v)
 	for_each_online_cpu(i) {
 		struct kernel_cpustat *kcs = &kcpustat_cpu(i);
 
+		kcpustat_cputime(kcs, i, &user, &nice,
+				 &system, &guest, &guest_nice);
 		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
-		user = kcs->cpustat[CPUTIME_USER];
-		nice = kcs->cpustat[CPUTIME_NICE];
-		system = kcpustat_field(kcs, CPUTIME_SYSTEM, i);
 		idle = get_idle_time(kcs, i);
 		iowait = get_iowait_time(kcs, i);
 		irq = kcs->cpustat[CPUTIME_IRQ];
 		softirq = kcs->cpustat[CPUTIME_SOFTIRQ];
 		steal = kcs->cpustat[CPUTIME_STEAL];
-		guest = kcs->cpustat[CPUTIME_GUEST];
-		guest_nice = kcs->cpustat[CPUTIME_GUEST_NICE];
 		seq_printf(p, "cpu%d", i);
 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
-- 
2.23.0