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sched, cgroup: Fixup broken cgroup movement

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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>
This commit is contained in:
Peter Zijlstra 2010-10-15 15:24:15 +02:00 committed by Ingo Molnar
parent b7dadc3879
commit b2b5ce022a
3 changed files with 24 additions and 11 deletions
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2
include/linux/sched.h
View File

@ -1073,7 +1073,7 @@ struct sched_class {
struct task_struct *task);
#ifdef CONFIG_FAIR_GROUP_SCHED
void (*moved_group) (struct task_struct *p, int on_rq);
void (*task_move_group) (struct task_struct *p, int on_rq);
#endif
};

8
kernel/sched.c
View File

@ -8498,12 +8498,12 @@ void sched_move_task(struct task_struct *tsk)
if (unlikely(running))
tsk->sched_class->put_prev_task(rq, tsk);
set_task_rq(tsk, task_cpu(tsk));
#ifdef CONFIG_FAIR_GROUP_SCHED
if (tsk->sched_class->moved_group)
tsk->sched_class->moved_group(tsk, on_rq);
if (tsk->sched_class->task_move_group)
tsk->sched_class->task_move_group(tsk, on_rq);
else
#endif
set_task_rq(tsk, task_cpu(tsk));
if (unlikely(running))
tsk->sched_class->set_curr_task(rq);

25
kernel/sched_fair.c
View File

@ -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)
place_entity(cfs_rq, &p->se, 1);
p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime;
set_task_rq(p, task_cpu(p));
if (!on_rq)
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
};