lkml.org 
[lkml]   [2011]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] [107/275] sched, cgroup: Fixup broken cgroup movement
Date
2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
Commit: b2b5ce022acf5e9f52f7b78c5579994fdde191d4 upstream

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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1287150604.29097.1513.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
include/linux/sched.h | 2 +-
kernel/sched.c | 8 ++++----
kernel/sched_fair.c | 25 +++++++++++++++++++------
3 files changed, 24 insertions(+), 11 deletions(-)

Index: linux-2.6.35.y/include/linux/sched.h
===================================================================
--- linux-2.6.35.y.orig/include/linux/sched.h 2011-03-29 23:03:00.269293279 -0700
+++ linux-2.6.35.y/include/linux/sched.h 2011-03-29 23:54:57.628527856 -0700
@@ -1076,7 +1076,7 @@
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
};

Index: linux-2.6.35.y/kernel/sched.c
===================================================================
--- linux-2.6.35.y.orig/kernel/sched.c 2011-03-29 23:03:00.391290158 -0700
+++ linux-2.6.35.y/kernel/sched.c 2011-03-29 23:54:57.628527856 -0700
@@ -8332,12 +8332,12 @@
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);
Index: linux-2.6.35.y/kernel/sched_fair.c
===================================================================
--- linux-2.6.35.y.orig/kernel/sched_fair.c 2011-03-29 23:03:00.347291285 -0700
+++ linux-2.6.35.y/kernel/sched_fair.c 2011-03-29 23:54:57.628527856 -0700
@@ -3657,13 +3657,26 @@
}

#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

@@ -3715,7 +3728,7 @@
.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
};


\
 
 \ /
  Last update: 2011-03-30 23:51    [W:0.929 / U:3.248 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site