Messages in this thread | | | Subject | Re: [PATCH 1/2] sched: normalize sleeper's vruntime during group change | From | Mike Galbraith <> | Date | Wed, 29 Sep 2010 10:13:15 +0200 |
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On Tue, 2010-09-28 at 23:46 -0700, Dima Zavin wrote: > This adds a new callback, prep_move_task, to struct sched_class > to give sched_fair the opportunity to adjust the task's vruntime > just before setting its new group. > > This allows us to properly normalize a sleeping task's vruntime > when moving it between different cgroups.
> diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c > index db3f674..008fe57 100644 > --- a/kernel/sched_fair.c > +++ b/kernel/sched_fair.c > @@ -3827,10 +3827,23 @@ static void set_curr_task_fair(struct rq *rq) > static void moved_group_fair(struct task_struct *p, int on_rq) > { > struct cfs_rq *cfs_rq = task_cfs_rq(p); > + struct sched_entity *se = &p->se; > > update_curr(cfs_rq); > - if (!on_rq) > + if (!on_rq) { > + se->vruntime += cfs_rq->min_vruntime; > place_entity(cfs_rq, &p->se, 1); > + } > +}
I'm still missing the place_entity() rationale. Why is a sleeping task eligible for pain therapy that a runnable task is spared? That state can change a usec from now.
Nit: place_entity(cfs_rq, se, 1);
-Mike
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