[PATCH 3/4] scheduler: cpuacct: Enable platform callbacks for cpuacct power tracking

[Mike Chan]

Platform must register cpu power function that return power in
milliWatt seconds.

Signed-off-by: Mike Chan <m...@android.com>
---
 Documentation/cgroups/cpuacct.txt |    3 +++
 include/linux/cpuacct.h           |    4 +++-
 kernel/sched.c                    |   24 ++++++++++++++++++++++--
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/Documentation/cgroups/cpuacct.txt 
b/Documentation/cgroups/cpuacct.txt
index 600d2d0..84e471b 100644
--- a/Documentation/cgroups/cpuacct.txt
+++ b/Documentation/cgroups/cpuacct.txt
@@ -44,6 +44,9 @@ cpuacct.cpufreq file gives CPU time (in nanoseconds) spent at 
each CPU
 frequency. Platform hooks must be implemented inorder to properly track
 time at each CPU frequency.
 
+cpuacct.power file gives CPU power consumed (in milliWatt seconds). Platform
+must provide and implement power callback functions.
+
 cpuacct controller uses percpu_counter interface to collect user and
 system times. This has two side effects:
 
diff --git a/include/linux/cpuacct.h b/include/linux/cpuacct.h
index 9ff479e..effe842 100644
--- a/include/linux/cpuacct.h
+++ b/include/linux/cpuacct.h
@@ -31,7 +31,9 @@ struct cpuacct_cpufreq_calls {
         */
        void (*init) (void **cpuacct_data);
        void (*charge) (void *cpuacct_data,  u64 cputime, unsigned int cpu);
-       void (*show) (void *cpuacct_data, struct cgroup_map_cb *cb);
+       void (*cpufreq_show) (void *cpuacct_data, struct cgroup_map_cb *cb);
+       /* Returns power consumed in milliWatt seconds */
+       u64 (*power_usage) (void *cpuacct_data);
 };
 
 int cpuacct_register_cpufreq(struct cpuacct_cpufreq_calls *fn);
diff --git a/kernel/sched.c b/kernel/sched.c
index 6b6c45a..d55d8af 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8838,12 +8838,28 @@ static int cpuacct_cpufreq_show(struct cgroup *cgrp, 
struct cftype *cft,
                struct cgroup_map_cb *cb)
 {
        struct cpuacct *ca = cgroup_ca(cgrp);
-       if (ca->cpufreq_fn && ca->cpufreq_fn->show)
-               ca->cpufreq_fn->show(ca->cpuacct_data, cb);
+       if (ca->cpufreq_fn && ca->cpufreq_fn->cpufreq_show)
+               ca->cpufreq_fn->cpufreq_show(ca->cpuacct_data, cb);
 
        return 0;
 }
 
+/* return total cpu power usage (milliWatt second) of a group */
+static u64 cpuacct_powerusage_read(struct cgroup *cgrp, struct cftype *cft)
+{
+       int i;
+       struct cpuacct *ca = cgroup_ca(cgrp);
+       u64 totalpower = 0;
+
+       if (ca->cpufreq_fn && ca->cpufreq_fn->power_usage)
+               for_each_present_cpu(i) {
+                       totalpower += ca->cpufreq_fn->power_usage(
+                                       ca->cpuacct_data);
+               }
+
+       return totalpower;
+}
+
 static struct cftype files[] = {
        {
                .name = "usage",
@@ -8862,6 +8878,10 @@ static struct cftype files[] = {
                .name =  "cpufreq",
                .read_map = cpuacct_cpufreq_show,
        },
+       {
+               .name = "power",
+               .read_u64 = cpuacct_powerusage_read
+       },
 };
 
 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
-- 
1.7.0.1

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