sched: retain vruntime

Kei Tokunaga reported an interactivity problem when moving tasks
between control groups.

Tasks would retain their old vruntime when moved between groups, this
can cause funny lags. Re-set the vruntime on group move to fit within
the new tree.

Reported-by: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9ae4030067a9..11d8e9a74eff 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -899,6 +899,10 @@ struct sched_class {
                              int running);
         void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
                              int oldprio, int running);
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+        void (*moved_group) (struct task_struct *p);
+#endif
 };
 
 struct load_weight {