Re: [PATCH 1/7 v4] sched: factorize attach entity

From: Vincent Guittot
Date: Wed Oct 12 2016 - 07:00:23 EST


On 7 October 2016 at 01:11, Vincent Guittot <vincent.guittot@xxxxxxxxxx> wrote:
>
> On 5 October 2016 at 11:38, Dietmar Eggemann <dietmar.eggemann@xxxxxxx> wrote:
> > On 09/26/2016 01:19 PM, Vincent Guittot wrote:
> >>
> >> Factorize post_init_entity_util_avg and part of attach_task_cfs_rq
> >> in one function attach_entity_cfs_rq
> >>
> >> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> >> ---
> >> kernel/sched/fair.c | 19 +++++++++++--------
> >> 1 file changed, 11 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> >> index 986c10c..e8ed8d1 100644
> >> --- a/kernel/sched/fair.c
> >> +++ b/kernel/sched/fair.c
> >> @@ -697,9 +697,7 @@ void init_entity_runnable_average(struct sched_entity
> >> *se)
> >> }
> >>
> >> static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq);
> >> -static int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool
> >> update_freq);
> >> -static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force);
> >> -static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct
> >> sched_entity *se);
> >> +static void attach_entity_cfs_rq(struct sched_entity *se);
> >>
> >> /*
> >> * With new tasks being created, their initial util_avgs are extrapolated
> >> @@ -764,9 +762,7 @@ void post_init_entity_util_avg(struct sched_entity
> >> *se)
> >> }
> >> }
> >
> >
> > You now could move the 'u64 now = cfs_rq_clock_task(cfs_rq);' into the
> > if condition to handle !fair_sched_class tasks.
>
> yes
>
> >
> >> - update_cfs_rq_load_avg(now, cfs_rq, false);
> >> - attach_entity_load_avg(cfs_rq, se);
> >> - update_tg_load_avg(cfs_rq, false);
> >> + attach_entity_cfs_rq(se);
> >> }
> >>
> >> #else /* !CONFIG_SMP */
> >> @@ -8501,9 +8497,8 @@ static void detach_task_cfs_rq(struct task_struct
> >> *p)
> >> update_tg_load_avg(cfs_rq, false);
> >> }
> >>
> >> -static void attach_task_cfs_rq(struct task_struct *p)
> >> +static void attach_entity_cfs_rq(struct sched_entity *se)
> >> {
> >> - struct sched_entity *se = &p->se;
> >> struct cfs_rq *cfs_rq = cfs_rq_of(se);
> >
> >
> > Both callers of attach_entity_cfs_rq() already use cfs_rq_of(se). You
> > could pass it into attach_entity_cfs_rq().
>
> Yes that would make sense

In fact there is a 3rd caller online_fair_sched_group which calls
attach_entity_cfs_rq and doesn't already use cfs_rq_of(se) so i
wonder if it's worth doing the interface change.


>
>
> >
> >> u64 now = cfs_rq_clock_task(cfs_rq);
> >> @@ -8519,6 +8514,14 @@ static void attach_task_cfs_rq(struct task_struct
> >> *p)
> >
> >
> > The old comment /* Synchronize task ... */ should be changed to /*
> > Synchronize entity ... */
>
> yes
>
> >
> >> update_cfs_rq_load_avg(now, cfs_rq, false);
> >> attach_entity_load_avg(cfs_rq, se);
> >> update_tg_load_avg(cfs_rq, false);
> >> +}
> >> +
> >> +static void attach_task_cfs_rq(struct task_struct *p)
> >> +{
> >> + struct sched_entity *se = &p->se;
> >> + struct cfs_rq *cfs_rq = cfs_rq_of(se);
> >> +
> >> + attach_entity_cfs_rq(se);
> >>
> >> if (!vruntime_normalized(p))
> >> se->vruntime += cfs_rq->min_vruntime;
> >>
> >
> > IMPORTANT NOTICE: The contents of this email and any attachments are
> > confidential and may also be privileged. If you are not the intended
> > recipient, please notify the sender immediately and do not disclose the
> > contents to any other person, use it for any purpose, or store or copy the
> > information in any medium. Thank you.
> >