| Message ID | 1466156921-12417-1-git-send-email-juri.lelli@arm.com |
|---|---|
| State | New |
| Headers | show |
On 17/06/16 11:58, Luca Abeni wrote: > Hi, > > On Fri, 17 Jun 2016 10:48:41 +0100 > Juri Lelli <juri.lelli@arm.com> wrote: > > > setup_new_dl_entity() takes two parameters, but it only actually uses > > one of them to setup a new dl_entity. > > > > Remove the second, useless, parameter. > > Funnily enough, I was adding something similar in my local queue :) > Looks good to me > Yeah, noticed this while looking at your reclaiming patches. :) Thanks for reviewing, - Juri > > > > > Cc: Ingo Molnar <mingo@redhat.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Steven Rostedt <rostedt@goodmis.org> > > Cc: Luca Abeni <luca.abeni@unitn.it> > > Signed-off-by: Juri Lelli <juri.lelli@arm.com> > > --- > > kernel/sched/deadline.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > index fcb7f0217ff4..5229788a4765 100644 > > --- a/kernel/sched/deadline.c > > +++ b/kernel/sched/deadline.c > > @@ -346,8 +346,7 @@ static void check_preempt_curr_dl(struct rq *rq, > > struct task_struct *p, > > * one, and to (try to!) reconcile itself with its own scheduling > > * parameters. > > */ > > -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, > > - struct sched_dl_entity *pi_se) > > +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) > > { > > struct dl_rq *dl_rq = dl_rq_of_se(dl_se); > > struct rq *rq = rq_of_dl_rq(dl_rq); > > @@ -367,8 +366,8 @@ static inline void setup_new_dl_entity(struct > > sched_dl_entity *dl_se, > > * future; in fact, we must consider execution overheads > > (time > > * spent on hardirq context, etc.). > > */ > > - dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline; > > - dl_se->runtime = pi_se->dl_runtime; > > + dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline; > > + dl_se->runtime = dl_se->dl_runtime; > > } > > > > /* > > @@ -1721,7 +1720,7 @@ static void switched_from_dl(struct rq *rq, > > struct task_struct *p) static void switched_to_dl(struct rq *rq, > > struct task_struct *p) { > > if (dl_time_before(p->dl.deadline, rq_clock(rq))) > > - setup_new_dl_entity(&p->dl, &p->dl); > > + setup_new_dl_entity(&p->dl); > > > > if (task_on_rq_queued(p) && rq->curr != p) { > > #ifdef CONFIG_SMP >
On 17/06/16 09:49, Steven Rostedt wrote: > On Fri, 17 Jun 2016 10:48:41 +0100 > Juri Lelli <juri.lelli@arm.com> wrote: > > > setup_new_dl_entity() takes two parameters, but it only actually uses > > one of them to setup a new dl_entity. > > > > Actually this patch is making it so that setup_new_dl_entity() only > uses one of the parameters. Can you note why that change happened. > Because this change log implies that the second parameter wasn't used > before this patch, and that is incorrect. > True, but we were practically already using the same parameter, under a different name though, after 2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity" as we currently do: setup_new_dl_entity(&p->dl, &p->dl) > This patch reverts part of the change done in > commit 2d3d891d334 "sched/deadline: Add SCHED_DEADLINE inheritance > logic" > Before Luca's change we were doing setup_new_dl_entity(dl_se, pi_se) in update_dl_entity() for a dl_se->new entity. So, I guess the question is actually why we wanted to use pi_se's parameters (the potential PI donor) for setting up a new entity? Maybe we broke the situation where a task is currently boosted by a DEADLINE waiter and we swich the holder to DEADLINE? > It would be nice to have the reason in the change log. > Thanks a lot for pointing out what might be more than inaccuracy in the changelog. Best, - Juri > > > Remove the second, useless, parameter. > > > > Cc: Ingo Molnar <mingo@redhat.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Steven Rostedt <rostedt@goodmis.org> > > Cc: Luca Abeni <luca.abeni@unitn.it> > > Signed-off-by: Juri Lelli <juri.lelli@arm.com> > > --- > > kernel/sched/deadline.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > index fcb7f0217ff4..5229788a4765 100644 > > --- a/kernel/sched/deadline.c > > +++ b/kernel/sched/deadline.c > > @@ -346,8 +346,7 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, > > * one, and to (try to!) reconcile itself with its own scheduling > > * parameters. > > */ > > -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, > > - struct sched_dl_entity *pi_se) > > +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) > > { > > struct dl_rq *dl_rq = dl_rq_of_se(dl_se); > > struct rq *rq = rq_of_dl_rq(dl_rq); > > @@ -367,8 +366,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, > > * future; in fact, we must consider execution overheads (time > > * spent on hardirq context, etc.). > > */ > > - dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline; > > - dl_se->runtime = pi_se->dl_runtime; > > + dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline; > > + dl_se->runtime = dl_se->dl_runtime; > > } > > > > /* > > @@ -1721,7 +1720,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) > > static void switched_to_dl(struct rq *rq, struct task_struct *p) > > { > > if (dl_time_before(p->dl.deadline, rq_clock(rq))) > > - setup_new_dl_entity(&p->dl, &p->dl); > > + setup_new_dl_entity(&p->dl); > > > > if (task_on_rq_queued(p) && rq->curr != p) { > > #ifdef CONFIG_SMP >
On 27/06/16 17:52, Peter Zijlstra wrote: > On Fri, Jun 17, 2016 at 05:28:37PM +0100, Juri Lelli wrote: > > On 17/06/16 09:49, Steven Rostedt wrote: > > > On Fri, 17 Jun 2016 10:48:41 +0100 > > > Juri Lelli <juri.lelli@arm.com> wrote: > > > > > > > setup_new_dl_entity() takes two parameters, but it only actually uses > > > > one of them to setup a new dl_entity. > > > > > > > > > > Actually this patch is making it so that setup_new_dl_entity() only > > > uses one of the parameters. Can you note why that change happened. > > > Because this change log implies that the second parameter wasn't used > > > before this patch, and that is incorrect. > > > > > > > True, but we were practically already using the same parameter, under a > > different name though, after > > > > 2f9f3fdc928 "sched/deadline: Remove dl_new from struct sched_dl_entity" > > > > as we currently do: > > > > setup_new_dl_entity(&p->dl, &p->dl) > > > > > This patch reverts part of the change done in > > > commit 2d3d891d334 "sched/deadline: Add SCHED_DEADLINE inheritance > > > logic" > > > > > > > Before Luca's change we were doing > > > > setup_new_dl_entity(dl_se, pi_se) > > > > in update_dl_entity() for a dl_se->new entity. So, I guess the question > > is actually why we wanted to use pi_se's parameters (the potential PI > > donor) for setting up a new entity? Maybe we broke the situation where a > > task is currently boosted by a DEADLINE waiter and we swich the holder > > to DEADLINE? > > > > > It would be nice to have the reason in the change log. > > > > > > > Thanks a lot for pointing out what might be more than inaccuracy in the > > changelog. > > Will you be reposting with a new Changelog? > Yes. Sorry, I didn't have much time to follow up on this. I actually think that a different change is required. Let's discuss that on v2. Best, - Juri
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index fcb7f0217ff4..5229788a4765 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -346,8 +346,7 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p, * one, and to (try to!) reconcile itself with its own scheduling * parameters. */ -static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, - struct sched_dl_entity *pi_se) +static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) { struct dl_rq *dl_rq = dl_rq_of_se(dl_se); struct rq *rq = rq_of_dl_rq(dl_rq); @@ -367,8 +366,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se, * future; in fact, we must consider execution overheads (time * spent on hardirq context, etc.). */ - dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline; - dl_se->runtime = pi_se->dl_runtime; + dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline; + dl_se->runtime = dl_se->dl_runtime; } /* @@ -1721,7 +1720,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p) static void switched_to_dl(struct rq *rq, struct task_struct *p) { if (dl_time_before(p->dl.deadline, rq_clock(rq))) - setup_new_dl_entity(&p->dl, &p->dl); + setup_new_dl_entity(&p->dl); if (task_on_rq_queued(p) && rq->curr != p) { #ifdef CONFIG_SMP
setup_new_dl_entity() takes two parameters, but it only actually uses one of them to setup a new dl_entity. Remove the second, useless, parameter. Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Juri Lelli <juri.lelli@arm.com> --- kernel/sched/deadline.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) -- 2.7.0