This is a note to let you know that I've just added the patch titled
sched, cgroup: Fixup broken cgroup movement
to the 2.6.32-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.32.git;a=summary
The filename of the patch is:
0023-sched-cgroup-Fixup-broken-cgroup-movement.patch
and it can be found in the queue-2.6.32 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.32 longterm
tree,
please let <[email protected]> know about it.
>From a77dfb9d34d1679ea857b18c980dc03399b4b90e Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <[email protected]>
Date: Thu, 10 Feb 2011 10:23:28 +0100
Subject: sched, cgroup: Fixup broken cgroup movement
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 <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Tested-by: Mike Galbraith <[email protected]>
LKML-Reference: <1287150604.29097.1513.camel@twins>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Mike Galbraith <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/sched.h | 2 +-
kernel/sched.c | 8 ++++----
kernel/sched_fair.c | 25 +++++++++++++++++++------
3 files changed, 24 insertions(+), 11 deletions(-)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1113,7 +1113,7 @@ 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
};
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -10224,12 +10224,12 @@ void sched_move_task(struct task_struct
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);
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -2068,13 +2068,26 @@ static void set_curr_task_fair(struct 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
@@ -2128,7 +2141,7 @@ static const struct sched_class fair_sch
.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
};
Patches currently in longterm-queue-2.6.32 which might be from
[email protected] are
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