Alex,
On Fri, Jun 21, 2013 at 10:39 AM, Alex Shi <seak...@gmail.com> wrote:
> On 06/21/2013 10:30 AM, Lei Wen wrote:
>> Hi Alex,
>>
>> On Thu, Jun 20, 2013 at 10:59 PM, Alex Shi <seak...@gmail.com> wrote:
>>> On 06/20/2013 10:46 AM, Lei Wen wrote:
>>>>
>>>>
>>>> But here I have a question, there is another usage of
>>>> __synchronzie_entity_decay
>>>> in current kernel, in the switched_from_fair function.
>>>>
>>>> If task being frequently switched between rt and fair class, would it
>>>> also bring the
>>>> redundant issue? Do we need patch like below?
>>>>
>>>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>>>> index b5408e1..9640c66 100644
>>>> --- a/kernel/sched/fair.c
>>>> +++ b/kernel/sched/fair.c
>>>> @@ -5856,7 +5856,7 @@ static void switched_from_fair(struct rq *rq,
>>>> struct task_struct *p)
>>>> */
>>>> if (p->se.avg.decay_count) {
>>>> struct cfs_rq *cfs_rq = cfs_rq_of(&p->se);
>>>> - se->avg.last_runnable_update +=
>>>> + p->se.avg.last_runnable_update +=
>>>
>>> what tree does this patch base on?
>>
>> I create the patch based on v3.9 kernel.
>> If it is ok, I could create a formal one based on latest kernel.
>
> In the linus tree, the first commit which introduced
> __synchronize_entity_decay(&p->se) here is
> 9ee474f55664ff63111c843099d365e7ecffb56f
> +
> +#if defined(CONFIG_FAIR_GROUP_SCHED) && defined(CONFIG_SMP)
> + /*
> + * Remove our load from contribution when we leave sched_fair
> + * and ensure we don't carry in an old decay_count if we
> + * switch back.
> + */
> + if (p->se.avg.decay_count) {
> + struct cfs_rq *cfs_rq = cfs_rq_of(&p->se);
> + __synchronize_entity_decay(&p->se);
> + subtract_blocked_load_contrib(cfs_rq,
> + p->se.avg.load_avg_contrib);
> + }
> +#endif
> }
>
> And it is never changed from then on. So your code must based on a
> incorrect kernel. please do a double check.
I see your point... I made the mistake that update the wrong patch...
Please help check this one.
commit 5fc3d5c74f8359ef382d9a20ffe657ffc237c109
Author: Lei Wen <lei...@marvell.com>
Date: Thu Jun 20 10:43:59 2013 +0800
sched: fix potential twice decay issue
Signed-off-by: Lei Wen <lei...@marvell.com>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c61a614..9640c66 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5856,7 +5856,8 @@ static void switched_from_fair(struct rq *rq,
struct task_struct *p)
*/
if (p->se.avg.decay_count) {
struct cfs_rq *cfs_rq = cfs_rq_of(&p->se);
- __synchronize_entity_decay(&p->se);
+ p->se.avg.last_runnable_update +=
+ __synchronize_entity_decay(&p->se);
subtract_blocked_load_contrib(cfs_rq,
p->se.avg.load_avg_contrib);
}
Thanks,
Lei
>>
>> Thanks,
>> Lei
>>
>>>> __synchronize_entity_decay(&p->se);
>>>> subtract_blocked_load_contrib(cfs_rq,
>>>> p->se.avg.load_avg_contrib);
>>>
>>>
>>> --
>>> Thanks
>>> Alex
>
>
> --
> Thanks
> Alex
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