From: Peter Zijlstra <[email protected]> ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
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: Paul Gortmaker <[email protected]> --- include/linux/sched.h | 2 +- kernel/sched.c | 8 ++++---- kernel/sched_fair.c | 25 +++++++++++++++++++------ 3 files changed, 24 insertions(+), 11 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 89e0fee..03e34c5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1071,7 +1071,7 @@ 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 }; diff --git a/kernel/sched.c b/kernel/sched.c index f7bc764..39456fc 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8275,12 +8275,12 @@ 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); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index b0f68035..f060583 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3668,13 +3668,26 @@ 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 @@ -3726,7 +3739,7 @@ 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 }; -- 1.7.4.4 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
