On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
> From: Kirill Tkhai <[email protected]>
>
> rq->curr task can't be in "dequeued" state in prio_changed_dl().
> (The only place we can have that is __schedule()). So, we delete
> rq->curr check.
the CBS timer can throttle it right?
В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет:
> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
> > From: Kirill Tkhai <[email protected]>
> >
> > rq->curr task can't be in "dequeued" state in prio_changed_dl().
> > (The only place we can have that is __schedule()). So, we delete
> > rq->curr check.
>
> the CBS timer can throttle it right?
Yeah, it's better to check for on_dl_rq():
[PATCH]sched/dl: Cleanup prio_changed_dl()
rq->curr task can't be in "dequeued" state in prio_changed_dl().
(The only place we can have that is __schedule()). So, we delete
rq->curr check.
We shouldn't do balancing if deadline task is throttled too.
Also delete "else" branch which is dead code (switched_to_dl()
is not interested in dequeued tasks and we are not interested
in balancing in this case).
Signed-off-by: Kirill Tkhai <[email protected]>
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 63f8b4a..ccea917 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1638,35 +1638,33 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
static void prio_changed_dl(struct rq *rq, struct task_struct *p,
int oldprio)
{
- if (task_on_rq_queued(p) || rq->curr == p) {
+ if (!on_dl_rq(&p->dl))
+ return;
#ifdef CONFIG_SMP
- /*
- * This might be too much, but unfortunately
- * we don't have the old deadline value, and
- * we can't argue if the task is increasing
- * or lowering its prio, so...
- */
- if (!rq->dl.overloaded)
- pull_dl_task(rq);
-
- /*
- * If we now have a earlier deadline task than p,
- * then reschedule, provided p is still on this
- * runqueue.
- */
- if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
- rq->curr == p)
- resched_curr(rq);
-#else
- /*
- * Again, we don't know if p has a earlier
- * or later deadline, so let's blindly set a
- * (maybe not needed) rescheduling point.
- */
+ /*
+ * This might be too much, but unfortunately
+ * we don't have the old deadline value, and
+ * we can't argue if the task is increasing
+ * or lowering its prio, so...
+ */
+ if (!rq->dl.overloaded)
+ pull_dl_task(rq);
+ /*
+ * If we now have a earlier deadline task than p,
+ * then reschedule, provided p is still on this
+ * runqueue.
+ */
+ if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
+ rq->curr == p)
resched_curr(rq);
+#else
+ /*
+ * Again, we don't know if p has a earlier
+ * or later deadline, so let's blindly set a
+ * (maybe not needed) rescheduling point.
+ */
+ resched_curr(rq);
#endif /* CONFIG_SMP */
- } else
- switched_to_dl(rq, p);
}
const struct sched_class dl_sched_class = {
Hi Kirill,
On 02/10/14 10:52, Kirill Tkhai wrote:
> В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет:
>> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
>>> From: Kirill Tkhai <[email protected]>
>>>
>>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>>> (The only place we can have that is __schedule()). So, we delete
>>> rq->curr check.
>>
>> the CBS timer can throttle it right?
>
> Yeah, it's better to check for on_dl_rq():
>
> [PATCH]sched/dl: Cleanup prio_changed_dl()
>
> rq->curr task can't be in "dequeued" state in prio_changed_dl().
> (The only place we can have that is __schedule()). So, we delete
> rq->curr check.
>
> We shouldn't do balancing if deadline task is throttled too.
>
> Also delete "else" branch which is dead code (switched_to_dl()
> is not interested in dequeued tasks and we are not interested
> in balancing in this case).
>
So, I agree that calling switched_to_dl() makes little sense,
but don't we have to deal with updates to not running tasks as
in rt.c? Something like this maybe?
>From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001
From: Juri Lelli <[email protected]>
Date: Tue, 21 Oct 2014 17:15:15 +0100
Subject: [PATCH] sched/deadline: cleanup prio_changed_dl()
---
kernel/sched/deadline.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 28d6088..1e62e31 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
static void prio_changed_dl(struct rq *rq, struct task_struct *p,
int oldprio)
{
- if (task_on_rq_queued(p) || rq->curr == p) {
+ if (!on_dl_rq(&p->dl))
+ return;
+
+ if (rq->curr == p) {
#ifdef CONFIG_SMP
/*
* This might be too much, but unfortunately
@@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
*/
resched_curr(rq);
#endif /* CONFIG_SMP */
- } else
- switched_to_dl(rq, p);
+ } else {
+ /*
+ * This task is not running, so if its deadline is
+ * now more imminent than that of the current running
+ * task then reschedule.
+ */
+ if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
+ resched_curr(rq);
+ }
}
const struct sched_class dl_sched_class = {
--
2.1.0
Thanks,
- Juri
> Signed-off-by: Kirill Tkhai <[email protected]>
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 63f8b4a..ccea917 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1638,35 +1638,33 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
> static void prio_changed_dl(struct rq *rq, struct task_struct *p,
> int oldprio)
> {
> - if (task_on_rq_queued(p) || rq->curr == p) {
> + if (!on_dl_rq(&p->dl))
> + return;
> #ifdef CONFIG_SMP
> - /*
> - * This might be too much, but unfortunately
> - * we don't have the old deadline value, and
> - * we can't argue if the task is increasing
> - * or lowering its prio, so...
> - */
> - if (!rq->dl.overloaded)
> - pull_dl_task(rq);
> -
> - /*
> - * If we now have a earlier deadline task than p,
> - * then reschedule, provided p is still on this
> - * runqueue.
> - */
> - if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
> - rq->curr == p)
> - resched_curr(rq);
> -#else
> - /*
> - * Again, we don't know if p has a earlier
> - * or later deadline, so let's blindly set a
> - * (maybe not needed) rescheduling point.
> - */
> + /*
> + * This might be too much, but unfortunately
> + * we don't have the old deadline value, and
> + * we can't argue if the task is increasing
> + * or lowering its prio, so...
> + */
> + if (!rq->dl.overloaded)
> + pull_dl_task(rq);
> + /*
> + * If we now have a earlier deadline task than p,
> + * then reschedule, provided p is still on this
> + * runqueue.
> + */
> + if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
> + rq->curr == p)
> resched_curr(rq);
> +#else
> + /*
> + * Again, we don't know if p has a earlier
> + * or later deadline, so let's blindly set a
> + * (maybe not needed) rescheduling point.
> + */
> + resched_curr(rq);
> #endif /* CONFIG_SMP */
> - } else
> - switched_to_dl(rq, p);
> }
>
> const struct sched_class dl_sched_class = {
>
>
>
В Вт, 21/10/2014 в 17:24 +0100, Juri Lelli пишет:
> Hi Kirill,
>
> On 02/10/14 10:52, Kirill Tkhai wrote:
> > В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет:
> >> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
> >>> From: Kirill Tkhai <[email protected]>
> >>>
> >>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
> >>> (The only place we can have that is __schedule()). So, we delete
> >>> rq->curr check.
> >>
> >> the CBS timer can throttle it right?
> >
> > Yeah, it's better to check for on_dl_rq():
> >
> > [PATCH]sched/dl: Cleanup prio_changed_dl()
> >
> > rq->curr task can't be in "dequeued" state in prio_changed_dl().
> > (The only place we can have that is __schedule()). So, we delete
> > rq->curr check.
> >
> > We shouldn't do balancing if deadline task is throttled too.
> >
> > Also delete "else" branch which is dead code (switched_to_dl()
> > is not interested in dequeued tasks and we are not interested
> > in balancing in this case).
> >
>
> So, I agree that calling switched_to_dl() makes little sense,
> but don't we have to deal with updates to not running tasks as
> in rt.c? Something like this maybe?
Looks good. No objections from me.
>
> From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001
> From: Juri Lelli <[email protected]>
> Date: Tue, 21 Oct 2014 17:15:15 +0100
> Subject: [PATCH] sched/deadline: cleanup prio_changed_dl()
>
> ---
> kernel/sched/deadline.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 28d6088..1e62e31 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
> static void prio_changed_dl(struct rq *rq, struct task_struct *p,
> int oldprio)
> {
> - if (task_on_rq_queued(p) || rq->curr == p) {
> + if (!on_dl_rq(&p->dl))
> + return;
> +
> + if (rq->curr == p) {
> #ifdef CONFIG_SMP
> /*
> * This might be too much, but unfortunately
> @@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
> */
> resched_curr(rq);
> #endif /* CONFIG_SMP */
> - } else
> - switched_to_dl(rq, p);
> + } else {
> + /*
> + * This task is not running, so if its deadline is
> + * now more imminent than that of the current running
> + * task then reschedule.
> + */
> + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
> + resched_curr(rq);
> + }
> }
>
> const struct sched_class dl_sched_class = {
On 21/10/14 17:33, Kirill Tkhai wrote:
> В Вт, 21/10/2014 в 17:24 +0100, Juri Lelli пишет:
>> Hi Kirill,
>>
>> On 02/10/14 10:52, Kirill Tkhai wrote:
>>> В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет:
>>>> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
>>>>> From: Kirill Tkhai <[email protected]>
>>>>>
>>>>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>>>>> (The only place we can have that is __schedule()). So, we delete
>>>>> rq->curr check.
>>>>
>>>> the CBS timer can throttle it right?
>>>
>>> Yeah, it's better to check for on_dl_rq():
>>>
>>> [PATCH]sched/dl: Cleanup prio_changed_dl()
>>>
>>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>>> (The only place we can have that is __schedule()). So, we delete
>>> rq->curr check.
>>>
>>> We shouldn't do balancing if deadline task is throttled too.
>>>
>>> Also delete "else" branch which is dead code (switched_to_dl()
>>> is not interested in dequeued tasks and we are not interested
>>> in balancing in this case).
>>>
>>
>> So, I agree that calling switched_to_dl() makes little sense,
>> but don't we have to deal with updates to not running tasks as
>> in rt.c? Something like this maybe?
>
> Looks good. No objections from me.
>
Ok, thanks Kirill. I'll send out a proper patch soon.
Best,
- Juri
>>
>> From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001
>> From: Juri Lelli <[email protected]>
>> Date: Tue, 21 Oct 2014 17:15:15 +0100
>> Subject: [PATCH] sched/deadline: cleanup prio_changed_dl()
>>
>> ---
>> kernel/sched/deadline.c | 16 +++++++++++++---
>> 1 file changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index 28d6088..1e62e31 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
>> static void prio_changed_dl(struct rq *rq, struct task_struct *p,
>> int oldprio)
>> {
>> - if (task_on_rq_queued(p) || rq->curr == p) {
>> + if (!on_dl_rq(&p->dl))
>> + return;
>> +
>> + if (rq->curr == p) {
>> #ifdef CONFIG_SMP
>> /*
>> * This might be too much, but unfortunately
>> @@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
>> */
>> resched_curr(rq);
>> #endif /* CONFIG_SMP */
>> - } else
>> - switched_to_dl(rq, p);
>> + } else {
>> + /*
>> + * This task is not running, so if its deadline is
>> + * now more imminent than that of the current running
>> + * task then reschedule.
>> + */
>> + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
>> + resched_curr(rq);
>> + }
>> }
>>
>> const struct sched_class dl_sched_class = {
>
>
>
10/22/14, 12:24 AM, Juri Lelli:
> Hi Kirill,
>
> On 02/10/14 10:52, Kirill Tkhai wrote:
>> В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет:
>>> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
>>>> From: Kirill Tkhai <[email protected]>
>>>>
>>>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>>>> (The only place we can have that is __schedule()). So, we delete
>>>> rq->curr check.
>>> the CBS timer can throttle it right?
>> Yeah, it's better to check for on_dl_rq():
>>
>> [PATCH]sched/dl: Cleanup prio_changed_dl()
>>
>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>> (The only place we can have that is __schedule()). So, we delete
>> rq->curr check.
>>
>> We shouldn't do balancing if deadline task is throttled too.
>>
>> Also delete "else" branch which is dead code (switched_to_dl()
>> is not interested in dequeued tasks and we are not interested
>> in balancing in this case).
>>
> So, I agree that calling switched_to_dl() makes little sense,
> but don't we have to deal with updates to not running tasks as
> in rt.c? Something like this maybe?
>
> From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001
> From: Juri Lelli <[email protected]>
> Date: Tue, 21 Oct 2014 17:15:15 +0100
> Subject: [PATCH] sched/deadline: cleanup prio_changed_dl()
>
> ---
> kernel/sched/deadline.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 28d6088..1e62e31 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
> static void prio_changed_dl(struct rq *rq, struct task_struct *p,
> int oldprio)
> {
> - if (task_on_rq_queued(p) || rq->curr == p) {
> + if (!on_dl_rq(&p->dl))
I'm not sure if this should be task_on_rq_queued() check. All
check_class_changed() callsites dequeue entity if task_on_rq_queued() is
true which leads to on_dl_rq(&p->dl) always return false.
Regards,
Wanpeng Li
> + return;
> +
> + if (rq->curr == p) {
> #ifdef CONFIG_SMP
> /*
> * This might be too much, but unfortunately
> @@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
> */
> resched_curr(rq);
> #endif /* CONFIG_SMP */
> - } else
> - switched_to_dl(rq, p);
> + } else {
> + /*
> + * This task is not running, so if its deadline is
> + * now more imminent than that of the current running
> + * task then reschedule.
> + */
> + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
> + resched_curr(rq);
> + }
> }
>
> const struct sched_class dl_sched_class = {
Hi,
On 24/10/14 00:04, Wanpeng Li wrote:
> 10/22/14, 12:24 AM, Juri Lelli:
>> Hi Kirill,
>>
>> On 02/10/14 10:52, Kirill Tkhai wrote:
>>> В Чт, 02/10/2014 в 11:36 +0200, Peter Zijlstra пишет:
>>>> On Wed, Oct 01, 2014 at 01:04:35AM +0400, Kirill Tkhai wrote:
>>>>> From: Kirill Tkhai <[email protected]>
>>>>>
>>>>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>>>>> (The only place we can have that is __schedule()). So, we delete
>>>>> rq->curr check.
>>>> the CBS timer can throttle it right?
>>> Yeah, it's better to check for on_dl_rq():
>>>
>>> [PATCH]sched/dl: Cleanup prio_changed_dl()
>>>
>>> rq->curr task can't be in "dequeued" state in prio_changed_dl().
>>> (The only place we can have that is __schedule()). So, we delete
>>> rq->curr check.
>>>
>>> We shouldn't do balancing if deadline task is throttled too.
>>>
>>> Also delete "else" branch which is dead code (switched_to_dl()
>>> is not interested in dequeued tasks and we are not interested
>>> in balancing in this case).
>>>
>> So, I agree that calling switched_to_dl() makes little sense,
>> but don't we have to deal with updates to not running tasks as
>> in rt.c? Something like this maybe?
>>
>> From 75ee75a5fd76526baaed3ba8a58f3ff7daa89cd6 Mon Sep 17 00:00:00 2001
>> From: Juri Lelli <[email protected]>
>> Date: Tue, 21 Oct 2014 17:15:15 +0100
>> Subject: [PATCH] sched/deadline: cleanup prio_changed_dl()
>>
>> ---
>> kernel/sched/deadline.c | 16 +++++++++++++---
>> 1 file changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index 28d6088..1e62e31 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -1661,7 +1661,10 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
>> static void prio_changed_dl(struct rq *rq, struct task_struct *p,
>> int oldprio)
>> {
>> - if (task_on_rq_queued(p) || rq->curr == p) {
>> + if (!on_dl_rq(&p->dl))
>
> I'm not sure if this should be task_on_rq_queued() check. All
> check_class_changed() callsites dequeue entity if task_on_rq_queued() is
> true which leads to on_dl_rq(&p->dl) always return false.
>
Yes, to be able to change class/prio. But they also enqueue it back if
it was on_rq. So, on_dl_rq() helps us when the tasks is throttled.
Thanks,
- Juri
> Regards,
> Wanpeng Li
>
>> + return;
>> +
>> + if (rq->curr == p) {
>> #ifdef CONFIG_SMP
>> /*
>> * This might be too much, but unfortunately
>> @@ -1688,8 +1691,15 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
>> */
>> resched_curr(rq);
>> #endif /* CONFIG_SMP */
>> - } else
>> - switched_to_dl(rq, p);
>> + } else {
>> + /*
>> + * This task is not running, so if its deadline is
>> + * now more imminent than that of the current running
>> + * task then reschedule.
>> + */
>> + if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
>> + resched_curr(rq);
>> + }
>> }
>>
>> const struct sched_class dl_sched_class = {
>
>