sched: provide per cpu-cgroup option to notify on migrations
On systems where CPUs may run asynchronously, task migrations
between CPUs running at grossly different speeds can cause
problems.
This change provides a mechanism to notify a subsystem
in the kernel if a task in a particular cgroup migrates to a
different CPU. Other subsystems (such as cpufreq) may then
register for this notifier to take appropriate action when
such a task is migrated.
The cgroup attribute to set for this behavior is
"notify_on_migrate" .
Change-Id: Ie1868249e53ef901b89c837fdc33b0ad0c0a4590
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 74f45e1..bec78f5 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -104,6 +104,8 @@
struct task_group {
struct cgroup_subsys_state css;
+ bool notify_on_migrate;
+
#ifdef CONFIG_FAIR_GROUP_SCHED
/* schedulable entities of this group on each cpu */
struct sched_entity **se;
@@ -554,6 +556,11 @@
return autogroup_task_group(p, tg);
}
+static inline bool task_notify_on_migrate(struct task_struct *p)
+{
+ return task_group(p)->notify_on_migrate;
+}
+
/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
{
@@ -579,7 +586,10 @@
{
return NULL;
}
-
+static inline bool task_notify_on_migrate(struct task_struct *p)
+{
+ return false;
+}
#endif /* CONFIG_CGROUP_SCHED */
static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)