sched, cpuacct: export percpu cpuacct cgroup stats

This patch export per-cpu CPU cycle usage for a given cpuacct cgroup.
There is a need for a user space monitor daemon to track group CPU
usage on per-cpu base.  It is also useful for monitoring CFS load
balancer behavior by tracking per CPU group usage.

Signed-off-by: Ken Chen <kenchen@google.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 41b7e2d524d680e7498060d16c12748a50cddcb7..f53e2b8ef52153f8c8f95d48e28cf1afc0589d9e 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -9342,12 +9342,32 @@ out:
        return err;
 }
 
+static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
+                                  struct seq_file *m)
+{
+       struct cpuacct *ca = cgroup_ca(cgroup);
+       u64 percpu;
+       int i;
+
+       for_each_present_cpu(i) {
+               percpu = cpuacct_cpuusage_read(ca, i);
+               seq_printf(m, "%llu ", (unsigned long long) percpu);
+       }
+       seq_printf(m, "\n");
+       return 0;
+}
+
 static struct cftype files[] = {
        {
                .name = "usage",
                .read_u64 = cpuusage_read,
                .write_u64 = cpuusage_write,
        },
+       {
+               .name = "usage_percpu",
+               .read_seq_string = cpuacct_percpu_seq_read,
+       },
+
 };
 
 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)