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Subject[tip: sched/core] procfs: Use all-in-one vtime aware kcpustat accessor
The following commit has been merged into the sched/core branch of tip:

Commit-ID: 26dae145a76c3615588f263885904c6e567ff116
Gitweb: https://git.kernel.org/tip/26dae145a76c3615588f263885904c6e567ff116
Author: Frederic Weisbecker <frederic@kernel.org>
AuthorDate: Thu, 21 Nov 2019 03:44:27 +01:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 21 Nov 2019 07:33:24 +01:00

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>
---
fs/proc/stat.c | 56 +++++++++++++++++++++++++++----------------------
1 file changed, 31 insertions(+), 25 deletions(-)

diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 5c6bd0a..37bdbec 100644
--- 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));
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