sched/cpuacct: Introduce cpuacct.usage_all to show all CPU stats together

In current code, we can get cpuacct data from several files,
but each file has various limitations.

For example:

 - We can get CPU usage in user and kernel mode via cpuacct.stat,
   but we can't get detailed data about each CPU.

 - We can get each CPU's kernel mode usage in cpuacct.usage_percpu_sys,
   but we can't get user mode usage data at the same time.

This patch introduces cpuacct.usage_all, to show all detailed CPU
accounting data together:

 # cat cpuacct.usage_all
 cpu user system
 0 3809760299 5807968992
 1 3250329855 454612211
 ..

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/7744460969edd7caaf0e903592ee52353ed9bdd6.1466415271.git.zhaolei@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 677cd1ab33b7..bc0b309c3f19 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -240,6 +240,42 @@ static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
         return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
 }
 
+static int cpuacct_all_seq_show(struct seq_file *m, void *V)
+{
+        struct cpuacct *ca = css_ca(seq_css(m));
+        int index;
+        int cpu;
+
+        seq_puts(m, "cpu");
+        for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
+                seq_printf(m, " %s", cpuacct_stat_desc[index]);
+        seq_puts(m, "\n");
+
+        for_each_possible_cpu(cpu) {
+                struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+
+                seq_printf(m, "%d", cpu);
+
+                for (index = 0; index < CPUACCT_STAT_NSTATS; index++) {
+#ifndef CONFIG_64BIT
+                        /*
+                         * Take rq->lock to make 64-bit read safe on 32-bit
+                         * platforms.
+                         */
+                        raw_spin_lock_irq(&cpu_rq(cpu)->lock);
+#endif
+
+                        seq_printf(m, " %llu", cpuusage->usages[index]);
+
+#ifndef CONFIG_64BIT
+                        raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
+#endif
+                }
+                seq_puts(m, "\n");
+        }
+        return 0;
+}
+
 static int cpuacct_stats_show(struct seq_file *sf, void *v)
 {
         struct cpuacct *ca = css_ca(seq_css(sf));
@@ -294,6 +330,10 @@ static struct cftype files[] = {
                 .seq_show = cpuacct_percpu_sys_seq_show,
         },
         {
+                .name = "usage_all",
+                .seq_show = cpuacct_all_seq_show,
+        },
+        {
                 .name = "stat",
                 .seq_show = cpuacct_stats_show,
         },