procfs: Use all-in-one vtime aware kcpustat accessor

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: Al Viro <viro@zeniv.linux.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Link: https://lkml.kernel.org/r/20191121024430.19938-4-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 5c6bd0ae38022374d6bb1908ac1ccc05603b3e39..37bdbec5b402008c89413fec3c8ab84e92e006ff 100644 (file)
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -120,20 +120,23 @@ static int show_stat(struct seq_file *p, void *v)
        getboottime64(&boottime);
 
        for_each_possible_cpu(i) {
-               struct kernel_cpustat *kcs = &kcpustat_cpu(i);
-
-               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];
-               sum += kstat_cpu_irqs_sum(i);
-               sum += arch_irq_stat_cpu(i);
+               struct kernel_cpustat kcpustat;
+               u64 *cpustat = kcpustat.cpustat;
+
+               kcpustat_cpu_fetch(&kcpustat, i);
+
+               user            += cpustat[CPUTIME_USER];
+               nice            += cpustat[CPUTIME_NICE];
+               system          += cpustat[CPUTIME_SYSTEM];
+               idle            += get_idle_time(&kcpustat, i);
+               iowait          += get_iowait_time(&kcpustat, i);
+               irq             += cpustat[CPUTIME_IRQ];
+               softirq         += cpustat[CPUTIME_SOFTIRQ];
+               steal           += cpustat[CPUTIME_STEAL];
+               guest           += cpustat[CPUTIME_GUEST];
+               guest_nice      += cpustat[CPUTIME_USER];
+               sum             += kstat_cpu_irqs_sum(i);
+               sum             += arch_irq_stat_cpu(i);
 
                for (j = 0; j < NR_SOFTIRQS; j++) {
                        unsigned int softirq_stat = kstat_softirqs_cpu(j, i);
@@ -157,19 +160,22 @@ static int show_stat(struct seq_file *p, void *v)
        seq_putc(p, '\n');
 
        for_each_online_cpu(i) {
-               struct kernel_cpustat *kcs = &kcpustat_cpu(i);
+               struct kernel_cpustat kcpustat;
+               u64 *cpustat = kcpustat.cpustat;
+
+               kcpustat_cpu_fetch(&kcpustat, i);
 
                /* 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];
+               user            = cpustat[CPUTIME_USER];
+               nice            = cpustat[CPUTIME_NICE];
+               system          = cpustat[CPUTIME_SYSTEM];
+               idle            = get_idle_time(&kcpustat, i);
+               iowait          = get_iowait_time(&kcpustat, i);
+               irq             = cpustat[CPUTIME_IRQ];
+               softirq         = cpustat[CPUTIME_SOFTIRQ];
+               steal           = cpustat[CPUTIME_STEAL];
+               guest           = cpustat[CPUTIME_GUEST];
+               guest_nice      = cpustat[CPUTIME_USER];
                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));