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>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9ae4030..11d8e9a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -899,6 +899,10 @@
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 {
diff --git a/kernel/sched.c b/kernel/sched.c
index dcd553c..0b949c4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7625,6 +7625,11 @@
set_task_rq(tsk, task_cpu(tsk));
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ if (tsk->sched_class->moved_group)
+ tsk->sched_class->moved_group(tsk);
+#endif
+
if (on_rq) {
if (unlikely(running))
tsk->sched_class->set_curr_task(rq);
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3df4d46..e2a5305 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1353,6 +1353,16 @@
set_next_entity(cfs_rq_of(se), se);
}
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void moved_group_fair(struct task_struct *p)
+{
+ struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+ update_curr(cfs_rq);
+ place_entity(cfs_rq, &p->se, 1);
+}
+#endif
+
/*
* All the scheduling class methods:
*/
@@ -1381,6 +1391,10 @@
.prio_changed = prio_changed_fair,
.switched_to = switched_to_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ .moved_group = moved_group_fair,
+#endif
};
#ifdef CONFIG_SCHED_DEBUG