Hi Juri,
于 9/19/14, 5:22 PM, Juri Lelli 写道:
> When a task is using SCHED_DEADLINE and the user setschedules it to a different
> class its sched_dl_entity static parameters are not cleaned up. This causes a
> bug if the user sets it back to SCHED_DEADLINE with the same parameters again.
> The problem resides in the check we perform at the very beginning of
> dl_overflow():
>
> if (new_bw == p->dl.dl_bw)
> return 0;
>
> This condition is met in the case depicted above, so the function returns and
> dl_b->total_bw is not updated (the p->dl.dl_bw is not added to it). After this,
As you know there is no static parameter clear before this patch, so if
p->dl.dl_bw will decrease from dl_b->total_bw when the user setschedules
to a different class instead of dl?
Regards,
Wanpeng Li
> admission control is broken.
>
> This patch fixes the thing, properly clearing static parameters for a task
> that ceases to use SCHED_DEADLINE.
>
> Reported-by: Daniele Alessandrelli <[email protected]>
> Reported-by: Daniel Wagner <[email protected]>
> Reported-by: Vincent Legout <[email protected]>
> Tested-by: Luca Abeni <[email protected]>
> Signed-off-by: Juri Lelli <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Juri Lelli <[email protected]>
> Cc: Dario Faggioli <[email protected]>
> Cc: Michael Trimarchi <[email protected]>
> Cc: Fabio Checconi <[email protected]>
> Cc: [email protected]
> ---
> kernel/sched/core.c | 19 +++++++++++++++----
> kernel/sched/deadline.c | 2 ++
> kernel/sched/sched.h | 3 +++
> 3 files changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index ec1a286..581a429 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1776,6 +1776,20 @@ int wake_up_state(struct task_struct *p, unsigned int state)
> }
>
> /*
> + * This function clears the sched_dl_entity static params.
> + */
> +void __dl_clear_params(struct task_struct *p)
> +{
> + struct sched_dl_entity *dl_se = &p->dl;
> +
> + dl_se->dl_runtime = 0;
> + dl_se->dl_deadline = 0;
> + dl_se->dl_period = 0;
> + dl_se->flags = 0;
> + dl_se->dl_bw = 0;
> +}
> +
> +/*
> * Perform scheduler related setup for a newly forked process p.
> * p is forked by current.
> *
> @@ -1799,10 +1813,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
>
> RB_CLEAR_NODE(&p->dl.rb_node);
> hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> - p->dl.dl_runtime = p->dl.runtime = 0;
> - p->dl.dl_deadline = p->dl.deadline = 0;
> - p->dl.dl_period = 0;
> - p->dl.flags = 0;
> + __dl_clear_params(p);
>
> INIT_LIST_HEAD(&p->rt.run_list);
>
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 255ce13..4a51b14 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -1569,6 +1569,8 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
> if (hrtimer_active(&p->dl.dl_timer) && !dl_policy(p->policy))
> hrtimer_try_to_cancel(&p->dl.dl_timer);
>
> + __dl_clear_params(p);
> +
> #ifdef CONFIG_SMP
> /*
> * Since this might be the only -deadline task on the rq,
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 579712f..4890484 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -126,6 +126,9 @@ struct rt_bandwidth {
> u64 rt_runtime;
> struct hrtimer rt_period_timer;
> };
> +
> +void __dl_clear_params(struct task_struct *p);
> +
> /*
> * To keep the bandwidth of -deadline tasks and groups under control
> * we need some place where:
ping,
于 10/8/14, 8:32 PM, Wanpeng Li 写道:
> Hi Juri,
>
> 于 9/19/14, 5:22 PM, Juri Lelli 写道:
>> When a task is using SCHED_DEADLINE and the user setschedules it to a
>> different
>> class its sched_dl_entity static parameters are not cleaned up. This
>> causes a
>> bug if the user sets it back to SCHED_DEADLINE with the same
>> parameters again.
>> The problem resides in the check we perform at the very beginning of
>> dl_overflow():
>>
>> if (new_bw == p->dl.dl_bw)
>> return 0;
>>
>> This condition is met in the case depicted above, so the function
>> returns and
>> dl_b->total_bw is not updated (the p->dl.dl_bw is not added to it).
>> After this,
>
> As you know there is no static parameter clear before this patch, so
> if p->dl.dl_bw will decrease from dl_b->total_bw when the user
> setschedules to a different class instead of dl?
>
> Regards,
> Wanpeng Li
>
>> admission control is broken.
>>
>> This patch fixes the thing, properly clearing static parameters for a
>> task
>> that ceases to use SCHED_DEADLINE.
>>
>> Reported-by: Daniele Alessandrelli <[email protected]>
>> Reported-by: Daniel Wagner <[email protected]>
>> Reported-by: Vincent Legout <[email protected]>
>> Tested-by: Luca Abeni <[email protected]>
>> Signed-off-by: Juri Lelli <[email protected]>
>> Cc: Ingo Molnar <[email protected]>
>> Cc: Peter Zijlstra <[email protected]>
>> Cc: Juri Lelli <[email protected]>
>> Cc: Dario Faggioli <[email protected]>
>> Cc: Michael Trimarchi <[email protected]>
>> Cc: Fabio Checconi <[email protected]>
>> Cc: [email protected]
>> ---
>> kernel/sched/core.c | 19 +++++++++++++++----
>> kernel/sched/deadline.c | 2 ++
>> kernel/sched/sched.h | 3 +++
>> 3 files changed, 20 insertions(+), 4 deletions(-)
>>
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index ec1a286..581a429 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -1776,6 +1776,20 @@ int wake_up_state(struct task_struct *p,
>> unsigned int state)
>> }
>> /*
>> + * This function clears the sched_dl_entity static params.
>> + */
>> +void __dl_clear_params(struct task_struct *p)
>> +{
>> + struct sched_dl_entity *dl_se = &p->dl;
>> +
>> + dl_se->dl_runtime = 0;
>> + dl_se->dl_deadline = 0;
>> + dl_se->dl_period = 0;
>> + dl_se->flags = 0;
>> + dl_se->dl_bw = 0;
>> +}
>> +
>> +/*
>> * Perform scheduler related setup for a newly forked process p.
>> * p is forked by current.
>> *
>> @@ -1799,10 +1813,7 @@ static void __sched_fork(unsigned long
>> clone_flags, struct task_struct *p)
>> RB_CLEAR_NODE(&p->dl.rb_node);
>> hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
>> - p->dl.dl_runtime = p->dl.runtime = 0;
>> - p->dl.dl_deadline = p->dl.deadline = 0;
>> - p->dl.dl_period = 0;
>> - p->dl.flags = 0;
>> + __dl_clear_params(p);
>> INIT_LIST_HEAD(&p->rt.run_list);
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index 255ce13..4a51b14 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -1569,6 +1569,8 @@ static void switched_from_dl(struct rq *rq,
>> struct task_struct *p)
>> if (hrtimer_active(&p->dl.dl_timer) && !dl_policy(p->policy))
>> hrtimer_try_to_cancel(&p->dl.dl_timer);
>> + __dl_clear_params(p);
>> +
>> #ifdef CONFIG_SMP
>> /*
>> * Since this might be the only -deadline task on the rq,
>> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
>> index 579712f..4890484 100644
>> --- a/kernel/sched/sched.h
>> +++ b/kernel/sched/sched.h
>> @@ -126,6 +126,9 @@ struct rt_bandwidth {
>> u64 rt_runtime;
>> struct hrtimer rt_period_timer;
>> };
>> +
>> +void __dl_clear_params(struct task_struct *p);
>> +
>> /*
>> * To keep the bandwidth of -deadline tasks and groups under control
>> * we need some place where:
>
Hi,
On 21/10/14 13:15, Wanpeng Li wrote:
> ping,
>
> 于 10/8/14, 8:32 PM, Wanpeng Li 写道:
>> Hi Juri,
>>
>> 于 9/19/14, 5:22 PM, Juri Lelli 写道:
>>> When a task is using SCHED_DEADLINE and the user setschedules it to a
>>> different
>>> class its sched_dl_entity static parameters are not cleaned up. This
>>> causes a
>>> bug if the user sets it back to SCHED_DEADLINE with the same
>>> parameters again.
>>> The problem resides in the check we perform at the very beginning of
>>> dl_overflow():
>>>
>>> if (new_bw == p->dl.dl_bw)
>>> return 0;
>>>
>>> This condition is met in the case depicted above, so the function
>>> returns and
>>> dl_b->total_bw is not updated (the p->dl.dl_bw is not added to it).
>>> After this,
>>
>> As you know there is no static parameter clear before this patch, so
>> if p->dl.dl_bw will decrease from dl_b->total_bw when the user
>> setschedules to a different class instead of dl?
>>
We remove p->dl.dl_bw from dl_b->total_bw in dl_overflow(). Then this
patch introduces the clearing of p->dl params.
Thanks,
- Juri
>> Regards,
>> Wanpeng Li
>>
>>> admission control is broken.
>>>
>>> This patch fixes the thing, properly clearing static parameters for a
>>> task
>>> that ceases to use SCHED_DEADLINE.
>>>
>>> Reported-by: Daniele Alessandrelli <[email protected]>
>>> Reported-by: Daniel Wagner <[email protected]>
>>> Reported-by: Vincent Legout <[email protected]>
>>> Tested-by: Luca Abeni <[email protected]>
>>> Signed-off-by: Juri Lelli <[email protected]>
>>> Cc: Ingo Molnar <[email protected]>
>>> Cc: Peter Zijlstra <[email protected]>
>>> Cc: Juri Lelli <[email protected]>
>>> Cc: Dario Faggioli <[email protected]>
>>> Cc: Michael Trimarchi <[email protected]>
>>> Cc: Fabio Checconi <[email protected]>
>>> Cc: [email protected]
>>> ---
>>> kernel/sched/core.c | 19 +++++++++++++++----
>>> kernel/sched/deadline.c | 2 ++
>>> kernel/sched/sched.h | 3 +++
>>> 3 files changed, 20 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>>> index ec1a286..581a429 100644
>>> --- a/kernel/sched/core.c
>>> +++ b/kernel/sched/core.c
>>> @@ -1776,6 +1776,20 @@ int wake_up_state(struct task_struct *p,
>>> unsigned int state)
>>> }
>>> /*
>>> + * This function clears the sched_dl_entity static params.
>>> + */
>>> +void __dl_clear_params(struct task_struct *p)
>>> +{
>>> + struct sched_dl_entity *dl_se = &p->dl;
>>> +
>>> + dl_se->dl_runtime = 0;
>>> + dl_se->dl_deadline = 0;
>>> + dl_se->dl_period = 0;
>>> + dl_se->flags = 0;
>>> + dl_se->dl_bw = 0;
>>> +}
>>> +
>>> +/*
>>> * Perform scheduler related setup for a newly forked process p.
>>> * p is forked by current.
>>> *
>>> @@ -1799,10 +1813,7 @@ static void __sched_fork(unsigned long
>>> clone_flags, struct task_struct *p)
>>> RB_CLEAR_NODE(&p->dl.rb_node);
>>> hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
>>> - p->dl.dl_runtime = p->dl.runtime = 0;
>>> - p->dl.dl_deadline = p->dl.deadline = 0;
>>> - p->dl.dl_period = 0;
>>> - p->dl.flags = 0;
>>> + __dl_clear_params(p);
>>> INIT_LIST_HEAD(&p->rt.run_list);
>>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>>> index 255ce13..4a51b14 100644
>>> --- a/kernel/sched/deadline.c
>>> +++ b/kernel/sched/deadline.c
>>> @@ -1569,6 +1569,8 @@ static void switched_from_dl(struct rq *rq,
>>> struct task_struct *p)
>>> if (hrtimer_active(&p->dl.dl_timer) && !dl_policy(p->policy))
>>> hrtimer_try_to_cancel(&p->dl.dl_timer);
>>> + __dl_clear_params(p);
>>> +
>>> #ifdef CONFIG_SMP
>>> /*
>>> * Since this might be the only -deadline task on the rq,
>>> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
>>> index 579712f..4890484 100644
>>> --- a/kernel/sched/sched.h
>>> +++ b/kernel/sched/sched.h
>>> @@ -126,6 +126,9 @@ struct rt_bandwidth {
>>> u64 rt_runtime;
>>> struct hrtimer rt_period_timer;
>>> };
>>> +
>>> +void __dl_clear_params(struct task_struct *p);
>>> +
>>> /*
>>> * To keep the bandwidth of -deadline tasks and groups under control
>>> * we need some place where:
>>
>
>