2020-10-13 17:56:02

by Peter Zijlstra

Subject: Re: [PATCH] sched/deadline: Replace rq_of_dl_rq(dl_rq_of_se(dl_se)) with ... ...task_rq(dl_task_of(dl_se))

On Tue, Oct 13, 2020 at 10:31:40PM +0800, Qi Zheng wrote:
> The rq is already obtained in the dl_rq_of_se() function:
> struct task_struct *p = dl_task_of(dl_se);
> struct rq *rq = task_rq(p);
> So there is no need to do extra conversion.
>
> Signed-off-by: Qi Zheng <[email protected]>
> ---
> kernel/sched/deadline.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 6d93f4518734..f64e577f6aba 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1152,7 +1152,7 @@ void init_dl_task_timer(struct sched_dl_entity *dl_se)
> static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
> {
> struct task_struct *p = dl_task_of(dl_se);
> - struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se));
> + struct rq *rq = task_rq(p);
>
> if (dl_time_before(dl_se->deadline, rq_clock(rq)) &&
> dl_time_before(rq_clock(rq), dl_next_period(dl_se))) {
> @@ -1498,7 +1498,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se,
> replenish_dl_entity(dl_se, pi_se);
> } else if ((flags & ENQUEUE_RESTORE) &&
> dl_time_before(dl_se->deadline,
> - rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) {
> + rq_clock(task_rq(dl_task_of(dl_se))))) {
> setup_new_dl_entity(dl_se);
> }

Consider where we're going:

https://lkml.kernel.org/r/[email protected]

then a dl_entity is no longer immediately a task and the above is no
longer true.

2020-10-14 09:21:42

by Qi Zheng

Subject: Re: [PATCH] sched/deadline: Replace rq_of_dl_rq(dl_rq_of_se(dl_se)) with ... ...task_rq(dl_task_of(dl_se))

On 2020/10/13 下午11:48, Peter Zijlstra wrote:
> On Tue, Oct 13, 2020 at 10:31:40PM +0800, Qi Zheng wrote:
>> The rq is already obtained in the dl_rq_of_se() function:
>> struct task_struct *p = dl_task_of(dl_se);
>> struct rq *rq = task_rq(p);
>> So there is no need to do extra conversion.
>>
>> Signed-off-by: Qi Zheng <[email protected]>
>> ---
>> kernel/sched/deadline.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index 6d93f4518734..f64e577f6aba 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -1152,7 +1152,7 @@ void init_dl_task_timer(struct sched_dl_entity *dl_se)
>> static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
>> {
>> struct task_struct *p = dl_task_of(dl_se);
>> - struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se));
>> + struct rq *rq = task_rq(p);
>>
>> if (dl_time_before(dl_se->deadline, rq_clock(rq)) &&
>> dl_time_before(rq_clock(rq), dl_next_period(dl_se))) {
>> @@ -1498,7 +1498,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se,
>> replenish_dl_entity(dl_se, pi_se);
>> } else if ((flags & ENQUEUE_RESTORE) &&
>> dl_time_before(dl_se->deadline,
>> - rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) {
>> + rq_clock(task_rq(dl_task_of(dl_se))))) {
>> setup_new_dl_entity(dl_se);
>> }
>
> Consider where we're going:
>
> https://lkml.kernel.org/r/[email protected]
>
> then a dl_entity is no longer immediately a task and the above is no
> longer true.
>

Thanks for your reply, I saw in the patch below that the dl_rq_of_se()
has been changed to the rq_of_dl_se(), so the above is no longer needed.

[RFC PATCH v2 4/6] sched/deadline: Introduce deadline servers

In addition, when will the SCHED_DEADLINE server infrastructure is
expected to be integrated into the mainline? It looks great!

Peter Zijlstra <[email protected]> 于2020年10月13日周二 下午11:48写道：
>
> On Tue, Oct 13, 2020 at 10:31:40PM +0800, Qi Zheng wrote:
> > The rq is already obtained in the dl_rq_of_se() function:
> > struct task_struct *p = dl_task_of(dl_se);
> > struct rq *rq = task_rq(p);
> > So there is no need to do extra conversion.
> >
> > Signed-off-by: Qi Zheng <[email protected]>
> > ---
> > kernel/sched/deadline.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index 6d93f4518734..f64e577f6aba 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -1152,7 +1152,7 @@ void init_dl_task_timer(struct sched_dl_entity *dl_se)
> > static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
> > {
> > struct task_struct *p = dl_task_of(dl_se);
> > - struct rq *rq = rq_of_dl_rq(dl_rq_of_se(dl_se));
> > + struct rq *rq = task_rq(p);
> >
> > if (dl_time_before(dl_se->deadline, rq_clock(rq)) &&
> > dl_time_before(rq_clock(rq), dl_next_period(dl_se))) {
> > @@ -1498,7 +1498,7 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se,
> > replenish_dl_entity(dl_se, pi_se);
> > } else if ((flags & ENQUEUE_RESTORE) &&
> > dl_time_before(dl_se->deadline,
> > - rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) {
> > + rq_clock(task_rq(dl_task_of(dl_se))))) {
> > setup_new_dl_entity(dl_se);
> > }
>
> Consider where we're going:
>
> https://lkml.kernel.org/r/[email protected]
>
> then a dl_entity is no longer immediately a task and the above is no
> longer true.