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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-10-15 15:24:15 +0200
committerIngo Molnar <mingo@elte.hu>2010-10-22 14:16:45 +0200
commitb2b5ce022acf5e9f52f7b78c5579994fdde191d4 (patch)
tree15e7d1742b530cdbe7b0734378e7f043b9a5faac /kernel/sched_fair.c
parentb7dadc38797584f6203386da1947ed5edf516646 (diff)
sched, cgroup: Fixup broken cgroup movement
Dima noticed that we fail to correct the ->vruntime of sleeping tasks when we move them between cgroups. Reported-by: Dima Zavin <dima@android.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Mike Galbraith <efault@gmx.de> LKML-Reference: <1287150604.29097.1513.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r--kernel/sched_fair.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 74cccfae87a8..3acc2a487c18 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -3866,13 +3866,26 @@ static void set_curr_task_fair(struct rq *rq)
}
#ifdef CONFIG_FAIR_GROUP_SCHED
-static void moved_group_fair(struct task_struct *p, int on_rq)
+static void task_move_group_fair(struct task_struct *p, int on_rq)
{
- struct cfs_rq *cfs_rq = task_cfs_rq(p);
-
- update_curr(cfs_rq);
+ /*
+ * If the task was not on the rq at the time of this cgroup movement
+ * it must have been asleep, sleeping tasks keep their ->vruntime
+ * absolute on their old rq until wakeup (needed for the fair sleeper
+ * bonus in place_entity()).
+ *
+ * If it was on the rq, we've just 'preempted' it, which does convert
+ * ->vruntime to a relative base.
+ *
+ * Make sure both cases convert their relative position when migrating
+ * to another cgroup's rq. This does somewhat interfere with the
+ * fair sleeper stuff for the first placement, but who cares.
+ */
+ if (!on_rq)
+ p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime;
+ set_task_rq(p, task_cpu(p));
if (!on_rq)
- place_entity(cfs_rq, &p->se, 1);
+ p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime;
}
#endif
@@ -3924,7 +3937,7 @@ static const struct sched_class fair_sched_class = {
.get_rr_interval = get_rr_interval_fair,
#ifdef CONFIG_FAIR_GROUP_SCHED
- .moved_group = moved_group_fair,
+ .task_move_group = task_move_group_fair,
#endif
};