sched: rt-group: synchonised bandwidth period

Various SMP balancing algorithms require that the bandwidth period
run in sync.

Possible improvements are moving the rt_bandwidth thing into root_domain
and keeping a span per rt_bandwidth which marks throttled cpus.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 28 insertions, 0 deletions

diff --git a/kernel/user.c b/kernel/user.c
index 7132022a040c..5925c6887c10 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -193,6 +193,33 @@ static ssize_t cpu_rt_runtime_store(struct kobject *kobj,
 
 static struct kobj_attribute cpu_rt_runtime_attr =
         __ATTR(cpu_rt_runtime, 0644, cpu_rt_runtime_show, cpu_rt_runtime_store);
+
+static ssize_t cpu_rt_period_show(struct kobject *kobj,
+                                   struct kobj_attribute *attr,
+                                   char *buf)
+{
+        struct user_struct *up = container_of(kobj, struct user_struct, kobj);
+
+        return sprintf(buf, "%lu\n", sched_group_rt_period(up->tg));
+}
+
+static ssize_t cpu_rt_period_store(struct kobject *kobj,
+                                    struct kobj_attribute *attr,
+                                    const char *buf, size_t size)
+{
+        struct user_struct *up = container_of(kobj, struct user_struct, kobj);
+        unsigned long rt_period;
+        int rc;
+
+        sscanf(buf, "%lu", &rt_period);
+
+        rc = sched_group_set_rt_period(up->tg, rt_period);
+
+        return (rc ? rc : size);
+}
+
+static struct kobj_attribute cpu_rt_period_attr =
+        __ATTR(cpu_rt_period, 0644, cpu_rt_period_show, cpu_rt_period_store);
 #endif
 
 /* default attributes per uid directory */
@@ -202,6 +229,7 @@ static struct attribute *uids_attributes[] = {
 #endif
 #ifdef CONFIG_RT_GROUP_SCHED
         &cpu_rt_runtime_attr.attr,
+        &cpu_rt_period_attr.attr,
 #endif
         NULL
 };