Report usage in CFS cgroup

Report CPU usage in CFS Cgroup directories

Adds a cpu.usage file to the CFS cgroup that reports CPU usage in milliseconds for that cgroup's tasks

---

kernel/sched.c | 36 +++++++++++++++++++++++++++++++-----

1 file changed, 31 insertions(+), 5 deletions(-)

Index: container-2.6.23-mm1/kernel/sched.c
===================================================================
@@ -7005,15 +7005,41 @@ static u64 cpu_shares_read_uint(struct c

	return (u64) tg->shares;
}

-static struct cftype cpu_shares = {
- .name = "shares",
- .read_uint = cpu_shares_read_uint,
- .write_uint = cpu_shares_write_uint,
+static u64 cpu_usage_read(struct cgroup *cgrp, struct cftype *cft) +{
+ struct task_group *tg = cgroup_tg(cgrp);
+ int i;
+ u64 res = 0;
+ for_each_possible_cpu(i) {
+ unsigned long flags;
+ /*
+ * Lock to prevent races with updating 64-bit counters
+ * on 32-bit arches.
+ */
+ spin_lock_irqsave(&cpu_rq(i)->lock, flags);
+ res += tg->se[i]->sum_exec_runtime;
+ spin_unlock_irqrestore(&cpu_rq(i)->lock, flags);
+ }
+ /* Convert from ns to ms */
+ do_div(res, 1000000);
+ return res;
+}
+
+static struct cftype cpu_files[] = {
+ {
+ .name = "shares",
+ .read_uint = cpu_shares_read_uint,
+ .write_uint = cpu_shares_write_uint,
+ },
+ {
+ .name = "usage",
+ .read_uint = cpu_usage_read,
+ },
};

static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) {
- return cgroup_add_file(cont, ss, &cpu_shares);
+ return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
}

struct cgroup_subsys cpu_cgroup_subsys = {